A major French aquarium vendor has announced it will stop selling the “classic” round fish bowls because they are cruel, driving fish mad and killing them quickly.
The history of keeping fish (either for food or as pets) goes back thousands of years. Oftentimes, fish are kept in tanks or ponds, but at some point, the fish bowl became pretty popular, at least for some species of fish. It’s not clear when the fish bowl was invented, but according to legend, it was first created by Madame du Barry, mistress to King Louis XV in the 18th century. Whether or not this is true, fish bowls became widespread over the next couple of centuries, especially for Betta fish (Betta splendens) or goldfish (Carassius auratus).
Proponents of these fish bowls claim that since these fish cover relatively small habitats, a fish bowl should do for them. But the evidence suggests otherwise.
It’s not just that there’s not enough space for the fish (though that should be enough reason). The shape of fish bowls also creates a poor surface-to-air ratio, and the bowl doesn’t have room for a filter. It also distorts the animal’s field of view and is easy to jump from.
“People buy a goldfish for their kids on impulse, but if they knew what a torture it is, they would not do it. Turning round and round in a small bowl drives fish crazy and kills them quickly,” AgroBiothers CEO Matthieu Lambeaux told Reuters. The company, one of the leading aquarium vendors, announced it will no longer be selling any fish bowls.
In healthy conditions, goldfish can easily live up to 30 years or even more, but in fish bowls, they rarely make it past one year. Germany and a few other countries have banned fish bowls, but most countries (including France and the US) have no legislation on this. Lambeaux said the company worked to educate clients, but at this point, they simply refuse to offer any more fish bowls — although demand does exist. In previous years, the company would sell around 50,000 fish bowls a year.
“It is a French anachronism, that is why we decided to move. We cannot educate all our customers to explain that keeping fish in a bowl is cruel. We consider that it is our responsibility to no longer give consumers that choice,” Lambeaux said. He added that fish need ample space and clean water, that small bowls are driving fish crazy, and anyone considering an aquarium should have at least a minimum of equipment and expertise.
The problem of fish bowls is something people have been aware of for a long time. In a 1902 edition of the Freshwater Aquaria magazine, a commentary noted that “the common glass globe… has nothing whatever to recommend it, except perhaps to those who delight to have their unfortunate captives suspended by a chain from the ceiling in front of the window.” In 1910, botanist Hugo Mulertt noted that “the old-fashioned fish globe is about the worst vessel that can be selected for the keeping of goldfish as pets.” Over a century later, the old-fashioned fish globe still endures.
The welfare of ornamental fish is often overlooked, even though the trade of ornamental fish trade is now a multibillion-dollar industry, with legal trade estimated to be worth between 15 and 20 billion dollarsper year (and a burgeoning illegal industry as well).
Fish have highly underrated cognitive abilities, but as awareness and understanding of fish improves, the case for better welfare for them becomes stronger and stronger, and a movement in this sense seems to be gaining momentum.
The fact that companies are also starting to acknowledge this is encouraging, but overall, this is still just a small step.
Human culture and society are based on the idea of learning new things and teaching new generations how to do those things. But this approach, called cumulative culture, may not be unique to humans. According to a new study, chimps do the same thing.
Chimps don’t automatically know what to do when they come across nuts and stones. That simple bit of information may not seem like much on its own, but it actually says a lot about how they develop and pass knowledge.
Some groups of chimpanzees in Guinea have figured out that they can use tools to crack nuts; others have not. Researchers wanted to see whether other chimps can individually figure out how nut-cracking works, or if this knowledge is passed on in the group that figured it out. If this were indeed the case, it would mean that passing information is embedded into chimpanzee culture, much like it is embedded in human culture.
To get to the bottom of this, a team led by primatologist Kathelijne Koops from Zurich University set up an experiment where they exposed another chimpanzee group just 6 km away from a tool-using group to everything it needed to crack open nuts — they even provided them with palm nuts.
Initially, the chimps were excited by the stone tools. But they didn’t figure out how to crack the nuts, and over a few months, they gradually lost interest. The researchers then added a palm fruit to the experimental setup, to familiarize the chimps with the food source. They even cracked open some nuts and placed them on top of the stone tools, to give them a hint, and offered some easier-to-crack types of nuts.
But regardless of what they did, they couldn’t get the chimps to crack open the nuts without being shown how to do it.
“None of the Seringbara chimpanzees cracked nuts, nor attempted to do so. Hence, stimulus/local enhancement (nuts and stones) or end-state emulation (cracked-open nuts) did not elicit a nut-cracking (re-)innovation in these wild chimpanzees,” the researchers write in the study. “In sum, nut cracking was not independently (re-)innovated by wild Western chimpanzees in field experiments.”
This strongly suggests that cracking nuts is a behavior chimps teach among their group, much like humans do. It’s a form of social learning that allowed human culture to develop progressively more complex tools and technologies. This new finding would force us to re-think how unique human culture really is.
“Our findings suggest that chimpanzees acquire cultural behaviors more like humans and do not simply invent a complex tool use behavior like nut cracking on their own,” says Koops. “Our findings on wild chimpanzees, our closest living relatives, help to shed light on what it is (and isn’t!) that makes human culture unique. Specifically, they suggest greater continuity between chimpanzee and human cultural evolution than is normally assumed and that the human capacity for cumulative culture may have a shared evolutionary origin with chimpanzees.”
Previous experiments have suggested that captive primates can start using tools without being taught, but some researchers suspected that this may be because they observed humans using tools and learned this behavior from them. This new experiment seems to suggest this idea is true.
If humans and chimpanzees both exhibit cumulative culture, and since the two species are so closely related biologically, it’s plausible that cumulative culture was also a trait of our common ancestor with chimpanzees.
“Our findings suggest greater continuity between chimpanzee and human cultural evolution than is normally assumed,” the researchers conclude.
Size isn’t everything when it comes to gardens. According to a new study, the size of a garden doesn’t correlate with how much nectar its pollinators produce, which means that even small gardens can provide pollinators like bees with a large supply of food.
We tend to think of urban areas as problems for conservation, but what if they could also be a part of the solution?
Urban areas can play an important role in the conservation of pollinators, which are currently under threat, especially by pesticides but also by other threats. Urban areas currently cover 2% to 3% of the world’s land and can support substantial pollinator diversity, according to a new study. Among them, small, private gardens can play an important role for pollinators thanks to their flowering plants.
Gardening for the future
Private gardens vary in size, shape, soil type, topography, and amount of sunlight. People also manage their gardens in widely different ways. As a result, the abundance and composition of flowering plants (which is crucial for bees) vary dramatically among gardens; one garden with many flowers may be a delicious buffer for bees, while freshly mown lawns offer next to nothing.
In a new study, researchers from Bristol University carried out the first investigation of how the nectar supply of private gardens changes in space and time. They found that because small gardens can be so important, actions by independent gardeners can lead to a stable and diverse provision of food for pollinators, supporting bees in key areas.
“We knew that gardens were important habitats for UK pollinators, providing 85% of nectar sugar in urban landscapes and a great diversity of flowering plants. However, we didn’t know how nectar production varied between individual gardens or through the months of the year,” PhD student Nick Tew, lead author, said in a statement.
Gardens and pollinators
Tew and his team surveyed residential gardens in Bristol, choosing six regions of the city for garden surveys. They visited 59 gardens once per calendar month between March and October – covering most of the UK pollinator flight season. They recorded floral abundance in each garden and measured when pollinators can find more nectar.
The researchers found that individual gardens vary significantly in the quantity of nectar they supply, registering a higher nectar production in more affluent neighborhoods but not in large gardens. The supply of nectar reached its peak in July when more plants are in flower, but temporal patterns varied among each garden depending on what flowers they had.
Gardens with a larger flowering plant richness had a more stable nectar production, the study showed. In other words, individual decisions on how people manage gardens (and how many pollinator-friendly plants are included) can make a big difference for pollinators. The highest-nectar garden produced over 700 times more sugar than the lowest-nectar garden during the survey period.
“This means that everyone has the potential to help pollinators in a meaningful way, even with a small garden and there is a lot of room for improvement, with some gardens providing hundreds of times less food than others, depending on what people choose to plant, weed, prune or mow,” Nick Tew, lead author, said in a statement.
In their study, the researchers also included a set of recommendations for all gardeners out there. They suggested using nectar-rich shrubs with complementary flowering periods and flowers with an open shape for late summer and autumn, as most nectar is only accessible to long-tongued pollinators later in the year.
For a list of some of the flowers that are good for bees, check out this research by the University of Sussex.
Famous American poet Rodney Mckuen once said “cats have it all; admiration, an endless sleep, and company only when they want it”. If you have a cat (or more), it’s probably not that hard to relate to these lines. Cats receive a lot of praise only for being cute, and they’re always quick to enjoy a nice (and often lengthy) nap. But why do cats sleep so much? Turns out, there’s a good reason for that.
If you think cats are sleep addicts, that’s not exactly true. Similar to jaguars, ocelots, and some other members of their feline family, cats are actually crepuscular beings — they’re most active between sunset and sunrise (around twilight). The reason is that their prey is often crepuscular — so if you’re a cat and want to hunt something, that’s a good time to go about it. Many years ago (before we started domesticating them), when both cats and their prey lived in the wild, cats had to stay awake and hunt between dusk and dawn in search of food.
Hunting could be a very energy-demanding process for any animal, and cats can cover impressive ranges in their search for food. So in order to recharge themselves for the next hunt, cats have developed a habit of sleeping a lot during the day — after all, it doesn’t make much sense to spend extra energy. So evolution pushed cats to sleep so much, and particularly during the day, when humans tend to be most active.
Domestication of these furry animals by humans has certainly brought some changes in their behavior and lifestyle and nowadays, house cats at least don’t roam the wild during the night looking for mice and rabbits — but their sleep-wake cycle has remained largely unchanged. This is the big reason why, for cats, daytime (when we regularly interact with them) is for resting, and resting is serious business.
How much sleep is enough for my cat?
Cats usually require around 15 hours of sleep in a day, but this can vary. Kittens and aging cats tend to sleep more, even up to 20 hours. Active cats may sleep as little as 12 hours. Most of the time cats go through a slow-wave sleep (SWP), light sleep, or a catnap during which their nose and ears are in alert mode and they are sleeping in such a posture that they can evade instantly as soon as they sense any danger. A catnap usually lasts between 15 to 30 minutes.
At least 12-14 hours of sleep is required for cats and both REM and light sleep are important for their health because good sleep ensures better energy conservation, muscle repair, good immunity, and the overall well-being of cats. The diet of cats mostly consists of protein (meat, fish, milk, etc) so proper sleep is also needed for complete digestion of their protein intake.
However, as far as sleep timing is concerned there is no fixed time at which all cats prefer to go to sleep in the day. Cats have the ability to set their sleeping hours as per their feeding pattern, and one research also reveals that some cats adjust their sleep timing as per the activity of their owners.
What do cats dream about?
Only 25% of a cat’s total sleep is deep sleep and this is the time during which your cat may go through REM (rapid eye movement) sleep, a unique sleeping phase accompanied with dreams (yes, cats can also dream) and involves increased brain activity, it is also experienced by humans and birds. If your cat’s limbs are twitching or whiskers are showing a slight regular movement during her sleep, it is possible that she might be dreaming. Maybe dreaming about you… but probably not — research suggests they’re likely dreaming about being on the hunt.
However, there’s still a chance that your cat may be dreaming about you from time to time. Professor Dr. Nicholas Dodman from Cumming Vet School, New England told Metro in an interview that cats exhibit many of the physiological and behavioral characteristics that humans also manifest in their dreaming. It’s entirely possible, according to a report, that cats dream of a variety of things, from their prey to other cats to their owner petting them.
Why cats sleep more when it’s raining?
Factors like weather and temperature also affect a cat’s activity and sleeping pattern, and it has been found that on rainy and cold days, cats spent more time sleeping. If you are a cat owner, you may have noticed your cat often lying near the heating system in winters. This is because cats are warm-blooded animals like us which means that on a cold day they require more energy to keep their internal body temperature balanced.
Also, cats, in general, prefer sunny weather and don’t like the rainy season. Cats and water are rarely good friends, and there’s a good reason for this too: it’s hard for them to stay warm during the wet season, and they also hate the noise that comes from the clouds. Plus, if they do get wet, it’s very hard to dry out and the moisture on their skin and fur can easily make them catch a cold.
Cats also tend to sleep more when they feel safe, and tend to pick sleeping spaces where they feel nothing can disturb them. But more sleep is not always a good sign. If your normal-aged cat is sleeping more than 15-16 hours a day, it is possible that she could be suffering from boredom, physical pain, hyperthyroidism, depression, etc. These disorders occur more frequently in cats that are overweight and you should consult a vet if you notice a sudden change in the sleeping habits of your cat or if it sleeps excessively. Just like humans, cats’ sleep patterns can offer hints about their health.
Just like a good night’s sleep is important for the proper functioning of our body, a good day’s sleep is necessary for a cat’s well-being. So the next time your cat is yawning in front of you as you work, don’t call them lazy. They just have a different sleep setting than yours — and arguably a better one.
They have been around since the Eocene and have survived waves of extinction — but as is the case with many other species, the lowland tapir (Tapirus terrestris) is now under severe risk. Its original range was cut by over 98%, and human activity is the main driver.
The lowland tapir is the biggest land mammal native to South America. It weighs up to 250 kilograms (550 pounds) and can adapt to almost any habitat on the continent. Tapirs can also move across any terrain and are great swimmers, hiding when pursued by predators. They have a diet of over 200 plant species, eating fruits, leaves, twigs, bark, and even soils. All in all, it’s an adaptable creature with many evolutionary perks up its sleeve.
However, tapirs have low reproductive potential, with one offspring after a 13-month gestation and birth intervals of up to three years. This makes them susceptible to population declines by predators. Tapirs are also relatively easy to track, especially by humans — as their habit of fleeting to water doesn’t work against humans. Road-kill is also a big cause of tapir mortality, and they are also vulnerable to habitat destruction. In recent years, this has taken a massive toll on their population.
At the start of the 16th century, tapirs could be found all across the Atlantic Forest, which covers Brazil, Argentina, and Paraguay. But over the past 500 years, the situation drastically changed. By the 19th century, tapirs were eradicated from coastal areas and from lower slopes. Hunters extirpated most populations between the 1950s and 1970s. Human infrastructure did the rest.
Kevin Flesher from the Biodiversity Study Center and Patrícia Medici, coordinator of the Lowland Tapir Conservation Initiative, started studying tapirs in 1996, when their conservation status was largely unknown. Since then, they have visited over 90 reserves in the Atlantic Forest, talking to people, and also analyzed 217 date sets. He can now tell a comprehensive and disheartening story.
The challenged tapir
The study showed that there are at least 48 populations of tapirs in the Atlantic Forest, with a population that ranges 2,665 to 15,992 species occupying about 26,000 square kilometers of forest. Tapirs suffered a 98% reduction in their range since Europeans arrived and were removed from north of Bahia and from Rio de Janeiro in Brazil.
Hunting has been the main driver of tapirs’ declines, and in 14 of the populations studied there were confirmed tapir kills. Hunting still happens in over 95%of the forests inhabited by tapirs. Highways are also a big threat. The study identified road-kill as a cause of mortality in six of the eight reserves that are close to highways.
But there are also reasons for optimism. Key populations still survive, and we now know what the biggest threats are.
Some tapir populations remain all over the Brazilian states in the Atlantic Forest, in the Misiones province of Argentina and in nine forest reserves in Paraguay, the researchers found. The largest populations are those in Misiones and the neighboring Iguaçu and Turvo reserves, in Paraná and Rio Grande do Sul, respectively.
In the long-term, the researchers believe that isolation is the main threat, with almost 94% of the tapir populations vulnerable to extinction over the next century because of their small population size. The Atlantic Forest has been largely fragmented over the years because of deforestation, with most of the forests being of less than 50 hectares.
The researchers called for urgent measures to connect the isolated population of tapirs and ensure their long-term conservation. They are cautiously optimistic for the future, as after decades of conservation efforts the situation is starting to improve. Populations of tapirs appear to be stable or increasing, which a much better outlook then what we’ve seen in the past — although these are still only the first steps of an uphill battle.
As with tapirs, the world is facing a big biodiversity crisis, which some have called the sixth mass extinction; an extinction caused by humans. The size of wildlife populations has declined by two-thirds worldwide since the 1970s, according to WWF’s Living Planet Report from 2020. Almost 70% of the drop is explained by land conversion for farming and wildlife trade. The story of the tapirs is that of many other animals, and we have to take swift action if we want to ensure we don’t wipe these populations off the face of the planet.
Although pandas subsist almost entirely on bamboo, plants with very little nutritional value, they are all on the chubby side. While it’s true that the rare mammals compensate for the poor calorie content by eating up to 80 pounds of bamboo per day, a new study has revealed that symbiotic gut bacteria also play a crucial role in fattening pandas and preparing them for when only bamboo leaves are available to chew on.
Like other bears, giant pandas possess the digestive system of a carnivore, but they have evolved to depend almost entirely on various bamboo species. For most of the year, pandas feed on fibrous bamboo leaves, but during the shoot-eating season in late spring and early summer, they get to enjoy newly sprouted bamboo shoots that are rich in protein. It’s no coincidence that during this season they’re also at their chubbiest.
Researchers led by Fuwen Wei at the Institute of Zoology have been studying wild giant pandas living in the Qinling Mountains in central China for decades. Their research showed that the animals have a much higher level of a bacterium called Clostridium butyricum in their gut during the shoot-eating season compared with during the leaf-eating season.
That’s quite common since many animals experience a seasonal shift in their microbiota as a result of changes in the availability of food. For instance, some monkeys have different gut bacteria in the summer when they eat fresh leaves and fruit compared to the winter, when they mainly feed on tree bark. Humans are no exception — Hazda people, one of the last hunter-gatherer communities left in the world, experience similar shifts in their gut bacteria as the available food changes throughout the year.
In order to investigate whether the Clostridium butyricum was having any effect on the pandas’ metabolism, the researchers performed fecal transplants of panda poop collected from the wild to germ-free mice. The mice were then fed a bamboo-based diet that mimicked what the pandas normally eat for three weeks.
“For endangered and vulnerable wild animals, we can’t really run tests on them directly. Our research created a mouse model for future fecal transplant experiments that can help study wild animals’ gut microbiota,” said first author Guangping Huang, from the Institute of Zoology at the Chinese Academy of Sciences.
The rodents transplanted with the panda feces from the shoot-eating season gained significantly more weight and had more fat than mice transplanted with feces from the leaf-eating season. Both groups of mice consumed the same amount of food, which means the bacteria must be doing something to help the animals gain weight.
On closer inspection, the researchers in China found that a metabolic product of C. butyricum, butyrate, upregulates the expression of a circadian rhythm gene called Per2, which increases lipid synthesis and storage.
“This is the first time we established a causal relationship between a panda’s gut microbiota and its phenotype,” said Huang. “We’ve known these pandas have a different set of gut microbiota during the shoot-eating season for a long time, and it’s very obvious that they are chubbier during this time of the year.”
Identifying which microorganisms in the panda’s gut play crucial roles in their health is highly important for conservation. There are only a few thousands giant pandas left in the wild, and captured pandas need to be fed the right diet to prepare them for rewilding. The research may also benefit humans, as many diseases that afflict us can be treated with probiotics.
Imagine a goldfish swimming on a tank on wheels as it moves deliberately from one side of a room to the other. No, it’s not a sci-fi movie, nor a bizarre comedy. It’s actually a serious animal behavior and cognitive ability experiment. Researchers trained several goldfish to run a robotic vehicle so to explore whether the species could navigate on land — and it turns out, they’re not too bad.
It’s not the first time we’ve seen something like this. Back in 2019, researchers at the University of Richmond wanted to see what effect the environment a rat was raised in had on its capability to learn new tasks. To do so, the team came up with something more tricky than navigating a maze. They successfully taught rats how to drive.
In a new study, researchers from Ben-Gurion University created a water tank on wheels to see whether goldfish can learn to navigate on dry land. The experiment wanted to test whether a fish’s navigation skills are universal or limited. Using navigational skills in unfamiliar settings is known as domain transfer methodology, and it’s an important cognitive ability.
“The study hints that navigational ability is universal rather than specific to the environment. Second, it shows that goldfish have the cognitive ability to learn a complex task in an environment completely unlike the one they evolved in,” says Shachar Givon, a PhD student and the study’s lead author, said in a statement.
Is that fish driving?
The researchers used a fish-operated vehicle (FOV) with a special software and a motion-sensing camera so to monitor where the fish is swimming in the watery tank on wheels. An algorithm moves the tank based on the camera’s signaling, allowing the fish to drive the vehicle. The algorithm is powered by a program running on an open-source microcontroller called Raspberry Pi.
Before tests could begin, the researchers first had to teach the goldfish how to drive. Six fish were enrolled in a driving school and were subject to multiple 30-minute sessions. The goldfish were tasked with moving the vehicle toward a visual target – a pink-colored mark on the wall of the experiment room – visible through the clear sides of the tank.
The movement of the fish and its location was translated into instructions for the FOV, allowing it to move left, right, forward or backward. The fish had to face outside the tank in the direction it was moving towards for the vehicle to move in a specific direction. This means that if the fish was in the middle of the tank, no movement happened.
Once the driving school was completed, the researchers were ready to officially test the goldfish navigational skills. In order to check if the fish were actually navigating to the targets and not just memorizing movements, the researchers changed the starting position of the vehicle and also incorporated decoy targets in different colors.
All the six fish that participated in the experiment drove toward the visual target, even from different angles – which suggests the fishes understand the world around them. All fish also improved as they repeated the task. This means that the fish can learn from their environment and make any necessary changes, the researchers argued. In other words, this experiment just taught us a new thing about the cognitive abilities of fish.
“The fish were tasked to “drive” the FOV towards a visual target in the terrestrial environment, which was observable through the walls of the tank, and indeed were able to operate the vehicle, explore the new environment, and reach the target regardless of the starting point, all while avoiding dead-ends and correcting location,” the researchers wrote.
As the largest carnivorous marsupial in the world, the Tasmanian devil is strictly carnivorous, hunting frogs, birds, fish, and insects. But most of their meals actually consist of carrion. Yet Tasmanian Devils aren’t your typical scavengers that will devour anything they get their teeth on. Much to everyone’s surprise, researchers in Australia found that the devils have very specific tastes and dietary preferences, which furthermore can vary from individual to individual. That’s rather unheard of for scavengers but the rowdy devils are not ones to play by the rules.
“It’s a scavenger’s job to just be a generalist and take whatever it can find,” says Tracey Rogers, senior author of the study and a Professor at the School of Biology, Earth and Environmental Studies at the University of New South Wales.
“But we’ve found that most Tasmanian devils are actually picky and selective eaters—they’ve broken the laws of scavenging.”
Scavengers, also called carrion-feeders, are animals that feed partly or wholly on the bodies of dead animals. Vultures, crows, and hyenas are among the most famous scavengers in the animal kingdom, playing an important role in the food web by keeping the ecosystem free of carrion and recycling organic matter into ecosystems as nutrients.
One of the reasons scavengers have a place in the food web, somewhere between prey and predator, is that they are very flexible about what they eat. The American crow will eat mice, eggs, seeds, and nuts, for instance, making them highly adapted to virtually any environment, be it the wild or sprawling urban areas.
Part scavengers, Tasmanian devils have always been thought to eat just about anything — but it turns out they’re pickier than a toddler.
Anna Lewis, the lead author of the study and Ph.D. candidate at UNSW Science, laid traps in the island of Tasmania for a week at a time, catching around 10 devils per day. In total, they captured 71 individuals across seven different sites, from which they removed small whisker samples before releasing them back to the wild. Each bristle is embedded with isotopes from the food the devils ate in the past, thus revealing their diets.
Just around one in ten devils had a generalist diet, consisting of whatever food was available in their habitats. Most devils, however, chose to eat their favorite foods, such as wallabies, possums, and rosellas, and turn up their noses at unappealing carrion.
The heaviest devils also proved to be the pickiest eaters. This could mean either that size is a driving factor in their food choices or, alternatively, specializing in certain types of carrion helps them gain weight.
What’s more, there was a great deal of variation among individuals. Just like humans, individual devils have their favorite meals.
“We were surprised the devils didn’t want to all eat the same thing,” said Lewis in a statement.
“Most of them just decided, ‘No, this is my favorite food.'”
Lewis and colleagues go on to add in their study published in Ecology and Evolution that this behavior seems to be devil-specific. Sure, there may be other scavengers that are non-generalists, but we’ve yet to find others.
Other scavengers can’t afford the luxury of saying ‘no thanks!’ to whatever carrion comes their way. Vultures in Africa, for instance, have to compete with myriad other predators and scavengers for food. Once they smell carrion, they’ll swoop right in, no questions asked. Check, please!
But in Tasmania, Tasmanian devils are virtually at the top of the food chain, with little competition for carcasses. “Their main competition is just with each other,” said Professor Rogers.
Arcturus, one of the devils from the study, named after one of the brightest stars in the sky, likes to eat pademelon and wallabies. But every once in a while, he decides to go for something different, indulging in a snake or two.
“Tasmanian devils are these really cool scavengers that are doing something completely different to every other scavenger in the world,” says Ms. Lewis.
“We’re lucky to have them here in Australia,” she added, hoping to keep it that way. The numbers of Tasmanian devils have plummeted since the 1990s due to a variety of reasons, chief among them a serious epidemic called Devil Facial Tumor Disease (DFTD).
It’s only one of three transmissible cancers known to man (the other being in dogs and shellfish), but also one of the most unforgiving, having an almost 100% kill rate. Today, the population of the iconic Australian marsupial is down 90% and many researchers fear the devil may be doomed unless something is done about it — and fast.
Until scientists develop a viable treatment or vaccine for DFTD, conservation groups have focused on minimizing interactions between populations, even opting for capturing some devils until it’s safe to release them back into the wild. Dietary studies such as these may help inform conservationists what kind of diets the devils respond best to in order to maximize their odds of survival in captivity.
“From a conservation perspective, the findings could help us work out if we’re feeding devils the appropriate thing in captivity,” says Ms Lewis.
“At the moment, there’s a long list of foods that devils can eat, but it’s not specific in how often they eat all those foods or whether most only focus on a few different food types.”
Our planet is teeming with life — and it leaves traces everywhere it goes. These include conspicuous markings such as pawprints or abandoned nests, but also other traces invisible to the naked eye such as DNA. In the past decade, biologists have had great success identifying animal species and their abundance using environmental DNA (eDNA) gathered from the aquatic environment. Now, two different research groups using two different methods have independently shown that it is possible to do the same with eDNA sucked out of the air.
The blueprint of life is everywhere, even in the air you breathe
Biology fieldwork can be incredibly thrilling, but it’s always exhausting. Measuring fish, collecting insects, catching snakes, you name it — on and on for weeks or even months. That may be a blessing if you’re the kind of scientist who loves nature and the great outdoors, but it’s terribly frustrating when you have to work in very remote areas on the lookout for elusive species — and this is exactly where environmental DNA can come in to save the day (and your Ph.D. thesis).
Environmental DNA — essentially genetic material obtained directly from environmental samples (soil, sediment, water, etc.) without any obvious signs of biological source material — has emerged as an invaluable tool for monitoring past and present biodiversity. The method was first employed in sediment, revealing DNA from extinct and extant animals and plants, but has since been obtained from various terrestrial and aquatic environmental samples. However, air samples have been rarely used for proper eDNA analysis due to the inherent challenges dealing with a medium so prone to contamination and, well, in a constant flow of motion — that’s until now.
Two independent groups of researchers, one led by Assistant Professor Elizabeth Clare from York University in Canada, the other led by Associate Professor Kristine Bohmann from the Globe Institute at the University of Copenhagen, have provided the most robust evidence thus far that air eDNA can be a reliable tool for assessing biodiversity.
“My research group does lots of fieldwork in remote areas with difficult and elusive species. We were motivated partly because we face the challenge of monitoring these animals all the time. We also have a history of working to develop new methods for biodiversity monitoring. I was mainly motivated because I was asked to write a report for one of the UK government agencies on how we can best use DNA in future biomonitoring. I got to writing about sources of eDNA and realized that air was a largely unexplored area, particularly for animals. I decided to take up that challenge myself,” Clare told ZME Science. “The really exciting thing about this is just how well it worked. Both teams independently tried to do this, and use different approaches… but both were highly successful. This is really good evidence that this is a viable method. That it will work on a large scale.”
“In my group, we work with different aspects of environmental DNA analyses, including exploring novel eDNA sample types. One such novel sample type is air. Air surrounds everything and we set out to explore whether it is possible to filter animal DNA from the air and use it to detect them. If this was indeed possible we would not only push the boundaries for what can be done with environmental DNA but also demonstrate a novel and non-invasive tool to complement existing methods for monitoring terrestrial animals – something of great importance to inform conservation efforts,” Bohmann told ZME Science.
Zoos: the perfect testing ground for airborne eDNA
Both research teams selected local zoos as their sampling sites, which proved to be the perfect testing grounds for this ambitious undertaking. Zoos have an exact headcount of all the animal species and individuals they house. They also have exotic species that are impossible to find in the local urban environment or even the wild in their respective countries. “We knew that if we detected Tasmanian devils then the likelihood of that being anywhere else in Copenhagen would be slim,” Bohmann said.
Bohmann and doctoral student Christina Lynggaard collected air samples from three different locations at the zoo using three different sampling devices (a commercial water-based vacuum and two blower fans with filters attached). They sucked and filtered air from the okapi stable, the Rainforest house, and outside between the different zoo enclosures.
Elsewhere in the UK, at Hamerton Zoo Park, Clare’s team used vacuum pumps to collect more than 70 air samples from various locations around the zoo, both inside animal sleeping dwellings and outside in the general environment.
Better than camera traps
Clare’s study identified 25 different species of animals, 17 of which were zoo species such as tigers, lemurs, and dingoes. Some of the zoo animals they detected lived hundreds of meters away from the testing sites, despite the sizable drop in concentration, but this showed that the method can monitor species over a large surface area from a single whiff of air.
Bohmann detected 49 species from 40 samples, ranging from mammals and birds to reptiles and fish. These included two-toed sloths, boas, rhinos, ostriches, and guppies in the nearby pond. “We were absolutely amazed by the taxonomic range of the animals that we detected – from mammals to birds, reptiles, amphibians, and fish. And we were blown away by the number of detections: we detected no less than 6-21 animal species per sample,” she said.
The monitoring surface area could actually be much greater for air eDNA than anyone dared to believe. Both groups detected species that weren’t kept at the zoos but were native to the surrounding area. Although they live outside Hamerton Zoo, the scientists found evidence of the Eurasian hedgehog, a species endangered in the UK. The air samples from Copenhagen Zoo contained DNA belonging to the water vole and red squirrel. They also found DNA from chickens, cows, horses, and fish — which all makes sense since these are common food items for zoo animals.
But these remarkable results required more preparation and due diligence than other eDNA sampling methods. Obviously, air surrounds everything so the researchers had to take special precautions to avoid contaminating their collected filters both on route and inside the lab. This included sampling the air inside the lab itself, whose readings acted as a control.
“We set up a completely new lab dedicated to this project and this for us unknown eDNA sample type. Here we employed very strict guidelines known from ancient DNA workflows and we even sampled the air in the lab to be sure we did not have any contaminating DNA in the air. We also employed different negative controls and importantly positive controls of species not known to be in the zoo or surrounding area. This enabled us to trace whether there was any contamination between samples, simply because we would then see the positive control species appearing in our samples,” Bohmann said.
In the UK, Clare had to also deal with COVID restrictions besides the challenges of working with air samples. But it was all well worth it in the end — luckily the adorable zoo animals lent a helping paw.
“I was the only person allowed at the zoo during most of the collection and I traded off with my student and technician Frances. It was mid-winter and there was some light snow. That was actually really fun. The animals were super excited to have visitors and deeply curious about what we were doing. I had some equipment stolen by a curious tyra. I had lunch watching maned wolves wander around. That was special,” Clare said.
Biodiversity monitoring might never be the same again
Air sampling seems poised to change environmental monitoring and conservation for the better, joining the ranks of tried and tested eDNA methods like aquatic and terrestrial.
“The field of aquatic eDNA biomonitoring was kicked off over a decade ago and since these first proof-of-concept studies, it has grown tremendously. Having demonstrated air as a novel eDNA sample type for vertebrate monitoring is of course something we can do because we stand on the shoulders of all these technological developments and I think that is also what will enable us to adapt this tool to natural environments – and I can’t wait to get started!” Bohmann said.
“On land, we use eDNA from many sources. It’s been collected from soil, honey, snow, rain even from spraying leaves and collecting the runoff water. But we don’t have a real general approach the way the aquatic community does. We really need to look at how that technology has developed to guide the next steps in refining the technique for air. We have the advantage that we can model our approaches after theirs,” Claire said, adding that “the really nice thing is that now that the idea is out there we are seeing this growing fast. There are studies emerging collecting airborne DNA from plants, insects, birds… it’s going to develop quickly and that’s exciting.”
And the groundwork has been laid out not by one but two different research groups independently. How the two research teams thought of the same study at right about the same time is another story in itself.
“I think at first we were both shocked! Our research teams have known each other for a long time, and have collaborated before. It was a total surprise to find out we were both doing the same study. It was more shocking to find we were both doing it the same way at the same time and had even written and submitted papers within a few hours to the same location! I’ve only heard of that happening once before,” Claire said. “We were extremely lucky that Current Biology saw that very significant advantage as well and while the papers were treated independently and fully peer-reviewed like any other, they agreed that both would be on the same timeline. We are extremely excited that they will appear together and at this example of scientific cooperation. More of this needs to happen!”
“I cannot wait for the day where we can meet at a conference over a large beer and celebrate our achievements and talk about the journey we have been on together,” Bohmann added.
‘Measuring biodiversity from DNA in the air’ Elizabeth L. Clare, Chloe K. Economou, Frances J. Bennett, Caitlin E. Dyer, Katherine Adams, Benjamin McRobie, Rosie Drinkwater, Joanne E. Littlefair Current Biology (2021). DOI: 10.1016/j.cub.2021.11.064
‘Airborne environmental DNA for terrestrial vertebrate community monitoring’ Christina Lynggaard, Mads Frost Bertelsen, Casper V. Jensen, Matthew S. Johnson, Tobias Guldberg Frøslev, Morten Tange Olsen and Kristine Bohmann Current Biology (2021). DOI: 10.1016/j.cub.2021.12.014
We’ve hunted them to near-extinction in most parts of the world, but as it turns out, beavers (genus Castor) are very important for freshwater conservation and ecosystem stability. Using aerial images, researchers found that beavers have helped to create and preserve aquatic and wetland environments in Minnesota, serving as an essential component of the ecosystem.
Beavers are the second-largest rodent in the world, currently living in the forests of North America, South America Europe, and Asia. They are mainly known for their ability to build dams on rivers and streams, which slow the flow of water and raise water levels – creating ponds. They also build shelters (called lodges) where they live.
Beavers get a lot of bad rep for creating “chaos” on freshwater systems — pulling down trees, creating dams, and wreaking havoc on the local environment — but beavers are actually an important ally for ecosystems, and the chaos they produce is generally helpful. Dams and ponds help create and maintain wetlands, replenish groundwater and provide a more consistent water flow in streams. They also store nutrients for plants, improve water quality and reduce erosion of stream banks.
Researchers from the University of Minnesota investigated how beavers affect patterns in surface water dynamics across multiple spatial scales (pond, watershed, and regional scales) over a 70-year period (1948–2017) within five watersheds in northeastern Minnesota, United States. A beaver study at such a scale is unprecedented, they say.
“Although there are many studies on how beavers change ecosystems, the scale of this study is really unprecedented and, as a result, gave us the unique opportunity to understand how beavers transform and engineer ecosystems over long time periods and large spatial scales,” Tom Gable, coauthor of the study, said in a press statement.
The team used aerial images to assess temporal patterns of surface water area associated with beaver ponds, the influence of beavers on surface water area, and how this changed in time. They also looked at the variations in ponds occupied and abandoned by beavers and whether patterns in surface water varies across spatial scales.
Previous studies on beavers suggested that their impact on ecosystems doesn’t change across time or space. However, this research showed that beavers’ ecological impact can in fact change depending on the scale. “They can be key drivers of freshwater habitat diversity and promoting ecosystem stability,” Johnson-Bice, lead author, said in a statement.
The researchers also found that beavers are drivers of water retention, which means that restoring their populations to ecosystems they no longer inhabit could be a good way to meet freshwater conservation objectives. The more time beavers are present in an ecosystem, the more abandoned ponds contribute towards storing water, which helps protect the wetlands they inhabit.
Despite the beaver populations in the studied watersheds in Minnesota having big variations in their population size, the water storage was stable across the entire region. This is because changes in beaver population size in one watershed counterbalance the changes in other watersheds, which helped stabilized water storage, according to the researchers.
“We suggest beaver engineering could be used to increase surface water storage and promote freshwater conservation efforts in forested ecosystems. If given the opportunity to recolonize landscapes, beaver-created surface water can reach capacity levels within a relatively short period of time (< 20–40 years),” the team wrote.
The coronavirus can and did infect white-tailed deer, according to new research. The findings raise some concerns regarding our efforts to contain the virus, as deer could act as a ‘reservoir species’ igniting further outbreaks.
Researchers at the Ohio State University report that white-tailed deer have tested positive for recent or active coronavirus infections in Northeast Ohio. The results are based on samples taken between January and March of 2021.
While there have been no reported cases of COVID-19 spreading from deer to humans, the authors warn that seeing the virus take hold among deer could pose a threat to public health later down the line. The main concern is that deer could become a reservoir species for the coronavirus, making efforts to control or eradicate the pathogen much more difficult. It also raises the risk of reinfection with the strains currently circulating among deer, or with new strains that mutated through the interaction between the coronavirus and the deer.
“Based on evidence from other studies, we knew [deer] were being exposed in the wild and that in the lab we could infect them and the virus could transmit from deer to deer. Here, we’re saying that in the wild, they are infected,” explains Andrew Bowman, the study’s author and professor of veterinary preventive medicine at The Ohio State University.
“And if they can maintain it, we have a new potential source of SARS-CoV-2 coming into humans. That would mean that beyond tracking what’s in people, we’ll need to know what’s in the deer, too.”
The findings are based on nasal swabs taken from 360 wild white-tailed deer across nine different areas in Northeast Ohio. Genetic material indicative of a recent or active coronavirus infection was identified in over 35% (129) of the deer, in samples taken from six locations. Three different strains of the virus were identified in these tests.
The study builds on previous findings of coronavirus infection among white-tailed deer in Iowa, Illinois, Michigan, New York, and Pennsylvania.
The findings lead “toward the idea that we might actually have established a new maintenance host outside humans,” according to Bowman. The virus could mutate in deer, potentially creating an opportunity for new strains to reach humans. It’s also possible that the virus will circulate unmutated among deer while it continues to evolve in humans. If the general population loses immunity to these original strains, the deer could provide an avenue through which they could spill back into our communities.
It’s not yet clear how deer became infected with the coronavirus, nor what (if any) effect this has on their bodies. So far, the team is working on the assumption that the animals contracted the virus by drinking contaminated water, as the coronavirus is known to shed through human stool.
The paper “SARS-CoV-2 infection in free-ranging white-tailed deer” has been published in the journal Nature.
A whiff of catnip can send cats into a frenzy but it can also make mosquitoes buzz off. The plant’s active ingredient, nepetalactone, is a super effective natural insect repellent and scientists have only recently found out how catnip keeps insect pests at bay while at the same time driving felines of all shapes and sizes completely nuts.
Catnip (Nepeta cataria) is a minty, lemony herb originally from Europe and Asia, although you can also find it growing in the Americas, particularly along roads and highways. Felines, from domestic house cats to lions, exhibit an intoxicated response when sniffing catnip characterized by licking and chewing the plants, as well as face and head rubbing against the plants and rolling over on the ground. There are no pathophysiological effects though — catnip is completely harmless to cats.
That’s common knowledge for any cat owner. What may be news to you is that catnip has a long history of use both as herbal medicine and as a powerful insect repellent in Asia, particularly in China and Japan. In fact, studies suggest that catnip compounds could be just as effective, if not more, at warding off mosquitoes as DEET, the most widely used synthetic insect repellent. Same plant, two completely different effects.
This disparity can be attributed to a class of structurally related iridoids, in particular to two isomers of nepetalactone. A study from March 2021 by researchers at Northwestern University found that the insect repellent effect is owed to interactions with a pain and itch receptor called TRPA1.
Humans, along with most mammals, also have TRPA1 receptors but the plant has no effect on us.
“We discovered that catnip and its active ingredient nepetalactone activate the irritant receptor TRPA1, an ancient pain receptor found in animals as diverse as flatworms, fruit flies and humans,” said Marco Gallio, an associate professor of neurobiology at Northwestern. “We now think catnip is so aversive to so many insect species because it activates this widespread irritant receptor. What is particularly interesting is that, unlike wasabi or garlic compounds that also activate these receptors in humans, catnip appears to selectively activate the insect receptor. This explains why humans are indifferent to it, and provides a serious advantage for its use as a repellent.”
Plants like catnip and silver vine (Actinidia polygama) likely evolved to make a chemical that activates TRPA1 as a defense mechanism. Catnip’s ancestors weren’t worried by mosquitoes or fruit flies, but they are now all repelled due to the blanket effects against insects, plant-nibbling or not, of the catnip compounds.
These findings suggest that catnip compounds could be used as a great, natural insect repellent. We could take some cues from cats, which wisened up to this millennia ago. Also in a 2021 study, researchers in Japan found that the feline automatic response to nepetalactone is owed to activation of the μ-opioid system, which is known to regulate euphoric and rewarding effects in humans.
The Japanese researchers go on to add that the characteristic, adorable-looking response that cats have to catnip suggests an important adaptive function for cats. According to the researchers, the rubbing and rolling against the plants transfers nepetalactone onto the fur for chemical defense against mosquitoes and possibly against other biting arthropods. The fact that so many species of wild big cats share the same response supports this evolutionary hypothesis.
“As a consequence, this reduces the number of A. albopictus mosquitoes that land on the animal’s head, helping to protect from mosquito bites. These findings provide new insight into this well-known and characteristic plant-induced feline response, for which the biological function was first questioned in popular science culture more than 300 years ago,” the scientists wrote in the journal Science Advances.
While catnip doesn’t make humans high, we could learn a thing or two from feline herbal medicine, especially in those tormenting summer nights at the height of mosquito season. I know I’m stocking up on catnip spray on my next camping trip.
A little river in Mexico is the site of one of 2021’s most heartwarming tales — the reintroduction of a species that had gone extinct in the wild.
We often hear stories about animals going extinct, and they’re always heartbreaking. But, every so often, we get to hear of the reverse: a species that had gone extinct, being reintroduced into the wild. The waters of the Teuchitlán, a river in Mexico that flows near a town bearing the same name, can now boast the same tale.
Efforts by local researchers, conservationists, and citizens, with international support, have successfully reintroduced the tequila splitfin (Zoogoneticus tequila), a tiny fish that only lived in the Teuchitlán river but had gone extinct during the 1990s, to the wild.
In the 1990s, populations of the tequila splitfin began to dwindle in the Teuchitlán river. Eventually, it vanished completely.
Omar Domínguez, one of the researchers behind the program that reintroduced the species, and a co-authored of the paper describing the process, was a university student at the time and worried about the fish’s future. Pollution, human activity, and invasive, non-native species were placing great pressure on the tequila splitfin.
Now a 47-year-old researcher at the University of Michoacán, he recounts that then only the elderly in Teuchitlán remembered the fish — which they called gallito (“little rooster”) because of its brightly-colored, orange tail.
Conservation efforts started in 1998 when a team from the Chester Zoo in England, alongside members from other European institutions, arrived with several pairs of tequila splitfin from the aquariums of collectors and set up a lab to help preserve the species.
The first few years were spent reproducing the fish in aquariums. Reintroducing these to the river directly was deemed to be too risky. So Domínguez and his colleagues built an artificial pond on-site, in which the fish could breed in semi-captivity. The then-40 pairs of tequila splitfins were placed in this pond in 2012, and by 2014 they had multiplied to around 10,000 individuals.
By now, their results gave all the organizations involved in the effort (various zoos and wildlife conservation groups from Europe, the United States, and the United Arab Emirates) enough confidence to fund further experimentation. So the team set their sights on the river itself. Here, they studied the species’ interactions with local predators, parasites, microorganisms, and how they fit into the wider ecosystem of the area.
Then, they placed some of the tequila splitfins back into the river — inside floating cages. This step, too, was a marked success, and the fish multiplied quickly inside the cages. When their numbers grew large enough, around late 2017, the researchers marked the individual fish and set them free. In the next six months, their population increased by 55%, the authors report. The fish are still going strong, they add: in December 2021, they were seen inhabiting a new area of the river, where they were completely extinct in the past.
It’s not just about giving a species a new lease on life, the team explains. Their larger goal was to restore the natural equilibrium of the river’s ecosystem. Although there is no hard data on environmental factors in the past to compare with, Domínguez is confident that the river’s overall health has improved. Its waters are cleaner, the number of invasive species has declined, and cattle are no longer allowed to drink directly from the river in some areas.
Local communities were instrumental in the conservation effort.
“When I started the environmental education program I thought they were going to turn a deaf ear to us — and at first that happened,” Domínguez said.
However, the conservationists made sustained efforts to educate the locals through puppet shows, games, and educational materials, and presentations about zoogoneticus tequila. Among others, citizens were told about the ecological role of the species, and the part it plays in controlling dengue-spreading mosquitoes.
The tequila splitfin is currently listed as endangered on the IUCN’s red list.
The paper “Progress in the reintroduction program of the tequila splitfin in the springs of Teuchitlán, Jalisco, Mexico” has been published online by the IUCN CTSG (Conservation Translocation Specialist Group). An update on the project has been published in the magazine Amazonas.
In the 1940s, researchers studying wolf packs noticed that they formed strict strength-based hierarchies were a dominant male and a dominant female controlled the other individuals, deciding the order in which they were allowed to eat or mate. To describe this dominant pairs and subordinates, researchers introduced the terms ‘alpha’ (the chief), ‘beta’ (the debuty), or ‘omega’ wolf (the bottom of the rank). Later, these terms became ingrained in human consciousness and cultural lingo to describe dominance hierarchies in other contexts, including humans.
But there’s a problem. This entire designation is wrong. While it’s true that multiple wolves who share a small space in captivity will develop alpha- and beta-like hierarchies, wild wolves behave nothing like this. In the wild, a wolf pack is typically formed by monogamous parents and their puppies. Sometimes, the pack might also include older siblings aged one to three years old. That’s it.
The wolf pack is basically a tightly knit family unit consisting of “parents”, or “breeders”, and their offspring. Unless you’re ready to call your mom and dad ‘alpha’, these terms have no grounds in reality.
Where did the idea of ‘alpha’ wolves come from?
The notion of leading wolves that control a pack of subordinates can be traced to 1947, when Rudolf Schenkel wrote a paper titled Expressions Studies on Wolves, in which he described the behavior of ten wolves kept at the Basel Zoo in Switzerland in a relatively small pen about 10 by 20 meters. During his observations, Schenkel noticed that the highest-ranked males and females formed a pair.
“By continuously controlling and suppressing all types of competition within the same sex, both ‘alpha animals’ defend their social position,” Schenkel wrote.
The pack behaviors described by Schenkel, including the ‘alpha’ dominance hierarchy, proved highly influential and were picked up by other ecologists, including David Mech, the founder of the International Wolf Center and one of the world’s foremost experts on wolf ecology.
Mech published a book called “The Wolf: Ecology and Behavior of an Endangered Species,” written in 1968, which proved immensely popular and further ingrained the concept of the alpha wolf in the niche literature, with many other researchers citing the book. Other research performed in the 1960s and 1970s, all on wolves held in captivity, seemed to confirm the alpha wolf model.
But after he published the book, he noted that later studies on wolves in the wild showed that this model is outdated.
“That concept was based on the old idea that wolves fight within a pack to gain dominance and that the winner is the ‘alpha’ wolf,” Mech said.
“[The book was] republished in paperback in 1981, and currently still in print, despite my numerous pleas to the publisher to stop publishing it. Although most of the book’s info is still accurate, much is outdated. We have learned more about wolves in the last 40 years than in all of previous history,” he added.
Like other debunked or misinterpreted science that is somehow still popular, such as Darwin’s survival of the fittest (misunderstood by many as ‘the strongest are favored by nature to survive’) or John Locke’s Tabula Rasa, the alpha wolf is perhaps more widespread in popular culture than ever.
Why there are no alpha wolves
One of the implications of the ‘alpha’ of the pack is that individuals compete with others to become the top dog, typically through battle.
However, in the wild, the leading members of a pack are the breeders of the offspring. In other words, the vast majority of wolves that lead packs earn their position simply by mating and producing pups. For this reason, scientists now call leading wolves the “breeding male,” “breeding female,” or “male parent,” “female parent,” or the “adult male” or “adult female.”
This has been confirmed by many recent studies, including two papers published by David Mech in 1999 and 2000, who extraordinarily managed to make a wolf pack from Ellesmere Island in Canada acclimatize to his presence over the course of 13 summers. Mech was able to study the pack up close, sometimes from up to a meter away. “Dominance fights with other wolves are rare, if they exist at all. During my 13 summers where I observed the pack, I saw none,” Mech wrote in one of his articles.
Elsewhere, in Norway, Barbara Zimmermann and colleagues from the Inland Norway University of Applied Sciences studied wolf pack behavior using GPS devices. The typical Scandinavian wolf pack consists of six members, usually two parents and four puppies. The parents establish their territory by marking a large area of the forest with their scent, and then patrol and defend their territory from intruders.
During February and March, the wolves mate and offspring are born in May. While the female nurses the young in her den for the first couple of weeks, only the male hunts. The male parent eats as much prey as possible then comes back to the den and vomits food for the female to eat. Then, they switch roles, with the female going out to hunt and bring back food while the male guards the den.
“What is exciting about wolf pairs is that they are unbelievably faithful. They stay together all the time,” Zimmermann told Science Nordic, describing the monogamous nature of wolves.
“More than 70 percent of GPS positions from wolf pairs show they remain within 100 meters of each other. So they are incredibly dependent on each other,” she added.
By October, the offspring are big enough to follow the adults around, although they are not allowed to hunt. The pups get to eat whatever prey the adults bring home to the den in the evening. This is yet another dispelled notion of the alpha wolf pack, which suggests a pack of wolves hunts in teams and moves together at all times. In reality, the young wolves are gradually weaned off and typically hunt on their own when they leave the pack to establish their own families.
Most pups leave the pack when they are one year old. This usually happens in waves, with 1-2 pups leaving early, while the rest are forced to finally leave the pack when the parents make new offspring.
The young wolves go out in search of a mate and suitable area to claim as their own territory. In some situations, young wolves are allowed to forage in their parents’ territory for up to two more years.
In other places, such as Yellowstone National Park where wolves were reintroduced in 1995, the packs can be larger and several members may hunt together. But even these packs are exclusively formed of parents and offspring. It’s just that some are as old as four years of age. This situation is enabled by the fact that Yellowstone has a much higher prey density than other regions where wolves are endemic.
Other variations include packs where one of the deceased parents is replaced by a new partner, sometimes with cubs in tow. In larger packs, there may be situations where both mother and daughter give birth but the daughter is still subordinate to the mother, although she retains control of her own offspring. This latter situation may be the only instance where the term ‘alpha’ may be used.
However, in none of these outlined situations is there any evidence of strength-based dominance hierarchy that occupies the public’s mind. Instead, a wolf pack is a family unit where the parents (or in rare situations the grandparents) lead by virtue of being the ones that brought the rest of the pack to life.
Today, the term ‘alpha wolf’ is no longer in fashion among researchers specialized in wolf ecology. However, it is still in use in the vernacular and will probably remain so for the foreseeable future. Yet humans who subscribe to the idea of “alpha males” might want to keep in mind that this concept only applies to the behavior of captive and cornered creatures.
This article was originally published in July 2021.
When biologist Carel ten Cate heard rumors of a talking duck in Australia, he brushed it off like a comical anecdote, like any sane human being. But his curiosity got the better of him, so he tracked down a well-respected Australian scientist who first noticed this phenomenon more than three decades ago. After listening to verified footage showing an adult musk duck vocalizing the sounds of a door slamming or squeaking, a pony snorting, a man coughing, and even the all too familiar slur “You bloody fool!”, the Dutch biologist was simply stunned. Listen for yourself
Carel ten Cate’s encounter with this articulate duck led him down a rabbit hole in which he found more evidence that musk ducks (Biziura lobata) can mimic sounds from nature, as well as those made by humans.
This extraordinary ability, which was documented in the Philosophical Transactions of the Royal Society of London B, officially allows the musk duck to join an exclusive club of animals that are capable of acquiring vocalization through learning, which includes parrots, hummingbirds, and some songbirds, as well as some whales, seals, dolphins, and bats on the mammalian front.
“These sounds have been described before, but were never analysed in any detail and went so far unnoticed by researchers of vocal learning,” said ten Cate, who is a professor of animal behavior at the Leiden University, wrote in his study. His co-author is Australian scientist Peter J. Fullager, who first documented a musk duck imitating sounds over 30 years ago.
Nearly all mammals produce some vocal sounds, from dogs barking and howling to cattle lowing and mooing. Humans are very different in that they can string together sounds that have particular meanings, which we call words, allowing us to communicate with one another through language. But at the same time, while most mammals are born with innate vocalization abilities, humans are not.
We all need to learn how to speak and the brain processes that support this type of learning are still poorly understood. This is why studies such as this that probe acquired vocalization in other species are important for unraveling these processes.
Vocal learning refers to imitating sounds or producing completely new vocalizations, depending on the species involved. Central to this ability seems to be auditory feedback during development.
“Most species have a more innate ability to learn how to make sounds. But a few rare animals, including a handful of mammals and, of course, human beings, are vocal learners. They need auditory feedback to learn how to make the right sounds if they want to communicate,” said Michael Yartsev, assistant professor of bioengineering at the University of California, Berkeley, in a 2020 interview with the Dana Foundation.
Yartsev’s earlier studies with Egyptian fruit bats showed that individuals that have been isolated or exposed to unique acoustic environments right after they were born had different vocalizations than groups of bats that were raised normally.
“This suggests that their vocalizations have some plasticity. Our own work has shown that, even in adults, if you expose the bats to sound perturbation, they have the capacity to modify or adapt their vocalizations in a stable manner over prolonged periods of time. So, there are good indications that there is some form of plasticity there that we can investigate,” Yartsev said.
The musk ducks seem to be this way too. Besides the musk duck that imitated his former caretaker’s insults, ten Cate identified another musk duck that was raised alongside Pacific black ducks (Anas superciliosa), and consequently quacked like them. Both ducks were raised in captivity since they were hatchlings. Wild musk ducks sound very different and they do not care to acquire new sounds in their vocal repertoire, which also explains why their vocalization acquisition abilities have been overlooked until now — they apparently make for horrible pets.
Furthermore, not all captive musk ducks seem to imitate non-native sounds. Captive female musk ducks don’t perform vocal displays, and the imitations performed by the males were part of their advertising displays to potential mates.
“Together with earlier observations of vocal differences between populations and deviant vocalizations in captive-reared individuals, these observations demonstrate the presence of advanced vocal learning at a level comparable to that of songbirds and parrots. We discuss the rearing conditions that may have given rise to the imitations and suggest that the structure of the duck vocalizations indicates a quite sophisticated and flexible control over the vocal production mechanism,” the scientists wrote in their new study.
Ducks split off from the evolutionary family tree sooner than other birds, such as parrots and songbirds. What’s more, duck brains differ quite a lot structure-wise than their avian relatives. Therefore, the “observations support the hypothesis that vocal learning in birds evolved in several groups independently rather than evolving once with several losses,” the researchers concluded.
This article was originally published in September, 2021.
Most bat species have little rodent-like faces but the hammer-headed bat (Hypsignathus monstrosus) is in a league of its own. The odd-looking flying mammal has a super elongated face that has many who see pictures of it on social media question its very existence. Yet despite its larger-than-life appearance, the hammer-headed bat is very much real.
The hammer-headed bat, also known as hammer-headed fruit bat and big-lipped bat, is a megabat species whose range is distributed across the tropical forests of central Africa. It prefers lowland moist forests, riverine forests, and swamp forests, as well as mangroves and palm forests where it roosts in the trees.
With a huge wingspan of up to 38 inches (97 cm), the hammerhead is Africa’s largest bat. Its average body length, however, is a much more modest 10 inches (25 cm). Males are significantly larger than females. In fact, it is the males that grow the large head with enlarged rostrum, larynx, and lips that make the species so recognizable, while the females look like other fruit bats.
Unlike other bat species that segregate based on sex, male and female hammer-headed bats will together in groups from as small as four to as large as twenty-five.
Males and females have different foraging strategies, with females using trap-lining, in which they travel an established route with predictable food sources even if that food may be of lower quality. Males employ a far riskier strategy, traveling up to 6 miles (10 km) in search of particularly good food patches. When the bats find the food they like, they may nibble at the tree a bit before picking some fruit and carrying it away to another site for consumption.
Their breeding season lasts one to three months. These bats exhibit classical lek mating, meaning many male suitors will congregate at a site and engage in competitive displays and courtship rituals, known as lekking, to entice visiting females. To woo females surveying for prospective mates, the males make a peculiar calling sound.
“I’m simply awestruck by hammer-headed fruit bats (Hypsignathus monstrosus). Close-up any given feature, eye, fur, nose, ear, wing, or foot, is extraordinary. In hand, whiskers appear in patterns seemingly unique to each individual, and the nasal and lip folds of the adult males, like the one shown, provide a sculptural finish to the overall moose-head look. As we handle them to collect samples, they show distinct behaviors ranging from docile to teeth masher, hence the thick leather gloves. Functionally, as the largest fruit bats in Africa (males weigh in around one pound), they are flying seed dispersal machines, critical to equatorial forest health,” wrote Sarah Olson, an associate director of wildlife health at the Wildlife Conservation Society (WCS), in a 2018 blog post.
Olson and colleagues have been studying these rather elusive bats for several years in order to better understand their ecology and behavior. Perhaps this may prove vitally important too in the future, considering all the hardship from the pandemic still fresh in everyone’s mind.
The hammer-headed bat is only one of three species of African fruit bats that can become asymptomatically infected with the dreaded Ebola virus, although scientists have yet to establish if the species is an incidental host or a reservoir of the virus.
“Aside from threats to human health, this deadly virus is linked to massive declines in populations of western lowland gorillas in Congo and Gabon. Our job as scientists is to find a way to prevent Ebola outbreaks and help conserve these bats for future generations, one bat at a time,” said Olson.
This article was originally published in June, 2021.
New research reports that at least one species of fish engages in similar behavior to sports fans — collective waves.
It’s not uncommon to see collective — also known as ‘Mexican’ — waves on arenas hosting football (soccer) matches around the world. These involve large groups of fans successively standing up in unison, as a display of solidarity between them and for their favorite teams.
Sulphur mollies (Poecilia sulphuraria), however, do it for a completely different purpose. A new paper describes this incredible collective behavior in the wild fish species, detailing how hundreds of thousands of individuals coordinate, likely to protect themselves from predatory birds.
“At first we didn’t quite understand what the fish were actually doing,” said David Bierbach, co-first author of the study. “Once we realized that these are waves, we were wondering what their function might be.”
The study showcases just how many of the fish partake in such behavior — there can be up to 4000 fish per square meter of ‘wave’, and each can include hundreds of thousands of individuals, according to the team.
Sulphur mollies are small animals, who stand out due to their preferred environment: sulphuric springs whose chemical make-ups make them toxic to most other species of fish.
The team explains that they likely use this living wave behavior as a way to confuse or maybe deter predators, especially birds. Mollies engage in this behavior when a person’s shadow falls on the water as well, further reinforcing this hypothesis. Individual waves last three to five seconds each, but the mollies have been recorded as repeating the behavior for up to two minutes.
The team first had to rule out the possibility that this behavior was random — their experiments showed that the fish would engage in ‘waves’ in a conspicuous, repetitive, and rhythmic fashion in response to stimuli associated with the presence of predators.
Then, they examined whether this behavior had any effect on the predators themselves: it does. The team reports that experimentally-induced fish waves dramatically reduced the frequency of attacks from birds of prey, and doubled the time these birds took between attacks. For one of their predator species (kiskadees, Pitangus sulphuratus), wave patterns also decreased capture probability.
Birds exposed to these wave patterns would switch perches more often than control individuals, suggesting that they may prefer to focus their attention on other prey when confronted with the mollies’ wave behavior.
According to the team, this is the first time a collective behavior has been shown to be directly responsible for reducing a species’ chances of being attacked and preyed upon. It is an important discovery for the study of collective behavior in animals more broadly, they add.
“So far scientists have primarily explained how collective patterns arise from the interactions of individuals but it was unclear why animals produce these patterns in the first place,” says co-author Jens Krause. “Our study shows that some collective behavior patterns can be very effective in providing anti-predator protection.”
Something that the team can’t yet explain is why such behavior helps protect the mollies from attacks. It’s possible that the motions confuse the birds, or perhaps they work as a signal to the bird that they have been spotted, making it consider another target altogether. The team plans to explore these questions in the future.
The paper “Fish waves as emergent collective antipredator behavior” has been published in the journal Current Biology.
Discovering dinosaur embryos is very rare but also very important in order to understand their development. Some have been found in the past but most have been incomplete, with bones dislocated. That’s why the discovery of a perfectly preserved embryo inside a fossilized egg has raised excitement among scientists.
The embryo, named “Baby Yingliang,” was hidden in storage for 15 years in the Yingliang Sone Nature Museum – until the curator found it in 2015. He saw some bones on the broken section of an egg and arranged for fossil preparation, which revealed the embryo’s skeleton. The museum then invited a team of paleontologists to study it.
“We are very excited about the discovery – it is preserved in a great condition and helps us answer a lot of questions about dinosaur growth and reproduction with it,” Fiona Waisum, a researcher at the University of Birmingham and joint first author, said in a statement. “Dinosaur embryos are some of the rarest fossils and most of them are incomplete with the bones dislocated.”
A very well conserved embryo
The fossilized egg was first found in 2000 in Ganzhou, Jiangxi Province in southern China by a mining company. The workers suspected it was likely dinosaur fossils, so they notified the museum for study. The embryo is 27-centimeters long and lies in a very rare posture for dinosaur fossils – its feet are on each side of the head and its back is curled alongside the egg.
If the posture sounds familiar, that’s because it’s similar to the hatching of a modern bird embryo. It’s a behavior known as “tucking,” which is critical for successful hatching. The position is supposed to help stabilize the head when a bird is breaking the eggshell with its beak. Failing to adopt it might lead to the death of the embryo.
Tucking is supposed to be unique to birds. But through comparisons of the posture of Baby Yingliang as well as other dinosaurs and birds, the team suggests that tucking could have evolved among theropod dinosaurs (bird’s ancestors) hundreds of million years ago. This adds up to other evidence of modern birds evolving from dinosaurs.
Based on its toothless and deep skull, the newly found embryo was identified by the researchers as an oviraptorosaur. These were a group of feathered theropod dinosaurs from the Cretaceous of Asia and North America related to modern birds. They had variable beak shapes and body sizes, allowing them to adopt different types of diets.
“This dinosaur embryo inside its egg is one of the most beautiful fossils I have ever seen. This little prenatal dinosaur looks just like a baby bird curled in its egg, which is yet more evidence that many features characteristic of today’s birds first evolved in their dinosaur ancestors,” Steve Brusatte, part of the team, said in a statement.
The study, published in iScience, was conducted by researchers from the China University of Geosciences and the University of Birmingham. Looking ahead, the team hopes to do more comprehensive comparisons of Baby Yingliang with embryos of modern birds and crocodiles – the closest living relatives of dinosaurs – so as to better understand the early development of dinosaurs.
It’s an unusual year for Australian music charts. An album made entirely of tweets and squawks from endangered bird species has entered the top five, surpassing the likes of Michael Bublé, Mariah Carey, and Justin Bieber to reach one of the top positions. Called Songs of Disappearance, the album features the songs of 53 threatened species, with all proceedings donated to BirdLife.
The album is the result of a collaboration between BirdLife, David Steward (who has recorded sounds of Australian birds during the last four decades), and the Bowerbird Collective – a project by performers Simone Slattery and Anthony Albrecht to explore the connection between art and science through a multimedia platform. Apparently, it’s quite the hit.
“The title track celebrates the incredible diversity of the Australian soundscape, and highlights what we stand to lose without taking action. Be immersed in a chorus of iconic cockatoos, the buzzing of bowerbirds, a bizarre symphony of seabirds, and the haunting call of one of the last remaining night parrots,” the album’s website reads.
Songs Of Disappearance is the first album of its type to appear in the top 10 of Australia’s Aria chart. It has already sold over 3,000 copies, including sounds from extremely rare species from Australia such as the regent honeyeater (Anthochaera phrygia) and the night parrot (Pezoporus occidentalis).
The album is currently fifth in Australia, just behind Adele’s 30, Ed Sheeran’s =, Paul Kelly’s Christmas Train, and Taylor Swift’s Red. The rest of the top 10 is formed by ABBA’s Voyage, Michael Bublé’s Christmas, Olivia Rodrigo’s Sour and Doja Cat’s Planet Her. The ranking changes every week. Needless to say, Songs of Disappearance is the first non-human entry on the list.
Birds under threat
As heartwarming as the album is, the situation of these birds is anything but uplifting.
A once-in-a-decade study published this month found that one in six Australian birds are currently threatened, with the climate crisis pushing species closer to extinction. Researcher Stephen Garnett of Charles Darwin University found that 216 out of 1,299 species are threatened – more than the 195 that were under threat back in 2011.
Of the 216 endangered birds, 87 were listed as vulnerable, 74 as endangered, 32 as near-threatened, 21 as critically endangered, and two as possibly extinct. The study found that 96 species are doing worse than a decade ago, listing them on a higher threat category. There were also 23 birds that are doing better and were downlisted.
Among the new birds under threat, the researchers identified 17 that live in cooler, higher-elevation rainforests in Queensland. The list includes the fernwren (Oreoscopus gutturalis), whose numbers have dropped almost 60% since 2000, the golden bowerbird (Prionodura newtoniana), and the Victoria’s riflebird (Ptiloris victoriae).
The study, known as the Action Plan for Australia’s Birds, found that global warming and the extreme weather events that it triggers such as bushfires were a key factor in the growing threat to Australia’s birds. The country was severely hit by bushfires a year ago, especially the New South Wales state, with over one billion trees that were burnt.
Although these two terms are used interchangeably, these two species are not the same. Although the differences between them are subtle, we can learn to tell the two apart. So let’s get to it!
Ravens and crows are closely related. They both belong to the Corvus genus of the Corvidae family of birds. Outwardly, they’re very similar — both are jet black and share several morphological features. Their natural ranges also have a lot of overlap, so they’re often seen (and mistaken for one another) in the same areas of the world.
Here is where the terms get a bit muddy, however. “Crow” is often used as a catch-all term for any bird in the genus Corvus. At the same time, people tend to refer to any larger bird from this genus as a “raven”. Taken together, it’s easy to see why very few people seem to be able to describe with any real detail what truly differentiates these species.
But — lucky you! — we’re about to go through them today.
Crow or raven?
One of the first indications that you’re seeing a crow rather than a raven is that the former generally travels in large groups, while the latter prefers to hang out in pairs. If we happen upon a solitary bird, however, such context clues won’t do us much good; so we’ll have to look at the characteristics of the individual.
Common ravens (Corvus corax) are, indeed, larger than your average crow. This is especially useful to know in rural areas, where size can be a pretty reliable indicator of which of these birds you’re dealing with. Ravens aren’t particularly fond of urban areas and their bustling crowds, however, so if you’re in a city, you’re probably more likely to be seeing a ‘really big crow’ than a raven. As a rule of thumb, crows are about the size of a pigeon and weigh on average 20 oz / o.55 kgs, while ravens are roughly as large as hawks, typically weighing 40 oz / 1.1 kgs.
Meanwhile “crows” — typically the Carrion Crow (Corvus corone) in Europe and American Crow (Corvus brachyrhynchos) in the U.S. — are quite fond of cityscapes and generally not people-shy.
The two species also produce different sounds. Crows vocalize through ‘caw’s or ‘purr’s (sound sample for carrion crows, American crows) while ravens use much lower, rougher croaks. Personally, I find the latter to sound much more ominous, and use this as a rough but reliable guideline when trying to identify ravens.
If vocalizations are not forthcoming, either, we can start looking at the physical features of the birds in question. As far as the plumage is concerned, both species sport jet-black feathers. Raven feathers are very glossy with green, blue, and purple iridescence; they can also have a wet or oily sheen. Crow feathers are iridescent blue and purple but are far less shiny than those of ravens (although they still do have a little bit of sheen to them).
Ravens have larger and curvier beaks than crows. Both sport bristles at the base of the beak, but for ravens, these are much more pronounced. Ravens tend to have ruffled feathers on the throat, whereas crows’ are swept neat and tidy.
On the ground, both birds behave similarly. One reliable way to tell a raven apart here, however, is by how they walk: ravens tend to mix little hops in their gait when moving more rapidly. At a slow pace, a raven’s walking pattern is the same as those employed by crows.
If you happen to spot the birds mid-flight, a few more tell-tale differences become apparent. A raven’s wingspan is much greater than that of a crow (3.5-4 ft / 1-1.2 m and 2.5 ft / 76 cm, respectively) and raven’s wing beats make a distinctive swishing sound while a crow’s are silent. In flight, the raven’s neck is also longer than a crow’s. Crows tend to actively flap their wings more often than ravens, which tend to prefer soaring on rising masses of air (they are heavier, and this helps them save energy). If you see such a bird soaring — gliding along with outstretched wings — for more than a few seconds at a time, chances are it’s a raven.
Ravens like to do all sorts of fancy acrobatics during flight, including somersaults (loops) or even flying upside-down, possibly just for fun. Such behavior is a dead giveaway that you’re looking at a raven, but it’s not very reliable; they tend to only engage in such playful behavior on windy days, or those with powerful thermals (rising masses of hot air) to keep them aloft.
As far as the shape of their wings is concerned, ravens have pointed wings with long primary feathers near their tip. Crows, meanwhile, have blunter wingtips; although their primaries are splayed as well, they are shorter and less pronounced than a raven’s.
Perhaps the single most distinctive difference between the two is the shape of their tails. All the feathers in a crow’s tail are the same length; in flight, their extended tails look like fans, with a rounded outline. Ravens meanwhile have longer feathers in the middle of their tails, giving them a wedge-like outline while the birds are in flight.
The differences between these two species are subtle — as well they should be, they are closely related, after all! The Corvidae family is also very numerous, and each species that belongs to it has its own particularities, some of which may not fit with what we’ve discussed here today. In general, however, they’re distinctive enough to tell apart.
Crows and ravens are some of the most similar — and most often-confused — species in this family. Hopefully the tips here will help you better tell them apart, and impress your friends with your knowledge of Corvidae!