The fossil of a 15-meter-long extinct species of dolphin is helping us better understand how different lineages of marine mammal independently evolved the same characteristics.
The species, christened Ankylorhiza tiedemani lived about 25 million years ago during the Oligocene in what today is South Carolina. It belonged to a group of large dolphins (Odontoceti) whose best-known modern representative is the orca (killer whale).
The anatomy of this fossil suggests that it was likely a top predator in its day. It shares several features with today’s baleen and toothed whales despite not being directly related to these groups, the authors report. This suggests that these animals evolved their shared swimming adaptations independently from one another, a phenomenon known as parallel evolution.
Like whales in a pod
“The degree to which baleen whales and dolphins independently arrive at the same overall swimming adaptations, rather than these traits evolving once in the common ancestor of both groups, surprised us,” says Robert Boessenecker of the College of Charleston in Charleston, South Carolina, first author of the paper describing this fossil.
“Some examples include the narrowing of the tail stock, increase in the number of tail vertebrae, and shortening of the humerus (upper arm bone) in the flipper.
Comparison with lineages of seals and sea lions reveal that the two families went down very different evolutionary paths as they transitioned from a land- to a marine-based lifestyle. The initial differences between these lineages were slight, the team explains: Ankylorhiza’s ancestors had one extra row of finger bones in their flippers and a “locking elbow joint”. Still, these factors lead to them developing different swimming styles and skeletal structures.
Another thing the authors note is that Ankylorhiza is the first echolocating whale to become an apex predator. According to the team, it was “very clearly preying upon large-bodied prey like a killer whale”. Its extinction cleared an ecological niche that sperm whales and a lineage of shark-toothed dolphins (both extinct) evolved into. Later still, killer whales would evolve into the same niche around 1 or 2 million years ago.
Ankylorhiza was first described from a skull fragment found during dredging of the Wando River, South Carolina, in the 1880s. A nearly-complete skeleton was later unearthed in the 1970s. The one described in this paper was found in the 1990s by commercial paleontologist Mark Havenstein at a building site and donated it to the Mace Brown Museum of Natural History to allow for its study.
“Whales and dolphins have a complicated and long evolutionary history, and at a glance, you may not get that impression from modern species,” Boessenecker says. “The fossil record has really cracked open this long, winding evolutionary path, and fossils like Ankylorhiza help illuminate how this happened.”
Boessenecker says that there are “many other unique and strange early dolphins and baleen whales from Oligocene aged rocks in Charleston, South Carolina,” including fossils of juvenile Ankylorhiza and specimens of related species. Both filter-feeding and echolocation first appeared during the Oligocene, he adds, so these fossils should give us a very good peek into how they came to be.
The paper “Convergent Evolution of Swimming Adaptations in Modern Whales Revealed by a Large Macrophagous Dolphin from the Oligocene of South Carolina” has been published in the journal Current Biology.
Drinking isn’t good for you, but watching parrots get drunk is both healthy and entertaining. Not for the parrots, though.
There’s no day like a weekend day — cause that’s when we get to party. But humans aren’t the only animals that like to abuse their systems with various chemicals. In fact, a lot of animals do it; and get into trouble afterward. We’ve seen the shenanigans that animals go through in love (and lust), some of which are amusingly similar to those we humans cause or experience. So let’s see whether our furry and feathered friends also mirror us in the bad choices we make on a night out on the town (spoiler: they do).
The Darwin Drinking Awards
Northern Australia is the only place on Earth that I know of which has three seasons: a wet season, a dry season, and a drunken parrot season.
Just before the wet season, roughly in mid-to-late December, the local Weeping Boer-bean trees (Schotia brachypetala) are flowering. This brings swarms of red-collared lorikeets to the area to feed on the nectar of the trees’ flowers. However, after a while, some of the birds start to sway a little bit — and then fall out of trees. Darwin locals report that the birds lack coordination and that they seemingly lose their ability to fly and sometimes even to walk. Vets say the birds act similar to drunken people. They also seem to experience disorientation, energy loss, and perhaps headaches, all very familiar hangover symptoms.
While the possibility of a virus affecting these birds hasn’t yet been ruled out, the event may have more to do with the trees — which are also known as the Drunken Parrot Tree, I’ll let you judge for yourself. So far, local animal caretakers and vets provide safe, quiet places for the parrots to recover — which can take months in some rare cases according to National Geographic — while providing sweetened porridge and fresh fruit. The prevailing theory is that the parrots get drunk off their tails on nectar and fruit fermented in the baking Australian heat.
Reindeer live in Siberia (in North America too, but they’re called caribou there). The hallucinogenic mushroom Amanita muscaria also lives in Siberia, among other places. And the reindeer like to get really, really high on the ‘shrooms during those long and dreary winter months.
Reindeer that partake of the mushrooms have been documented to act almost as if drunk, running around aimlessly, making strange noises, and twitching their heads.
“They have a desire to experience altered states of consciousness,” Huffington Post cites researcher Andrew Haynes, who studied the behavior in the wild. “For humans a common side-effect of mushrooms is the feeling of flying, so it’s interesting the legend about Santa’s reindeer is they can fly.”
He also adds that herdsmen drink the reindeer’s urine to get high themselves.
“Fly agaric is found across the northern hemisphere and has long been used by mankind for its psychotropic properties, but its use can be dangerous because it also contains toxic substances,” he explains for the Pharmaceutical Journal.
“Reindeer seem to metabolise these toxic elements without harm, while the main psychoactive constituents remain unmetabolised and are excreted in the urine. Reindeer herders in Europe and Asia long ago learnt to collect the reindeer urine for use as a comparatively safe source of the hallucinogen.”
Sharing, it seems, really is caring.
Wallabies are adorable, diminutive kangaroos native to Australia and New Guinea.
Opium poppy farmers on Tasmania (an island off the south Australian coast) have reported that wallabies will sometimes break into their fields to dine on the flowers, which are the raw material for prescription painkillers.
Although exactly which species of wallabies are responsible is still unknown, the animals have been seen eating poppies before running around in circles and eventually passing out, according to a BBC report. Lara Giddings, the attorney general for the island state of Tasmania even described the animals as being “high as a kite” and creating crop circles.
“The one interesting bit that I found recently in one of my briefs on the poppy industry was that we have a problem with wallabies entering poppy fields, getting as high as a kite and going around in circles,” Lara Giddings told a parliamentary hearing on security for poppy crops. “Then they crash.”
“We see crop circles in the poppy industry from wallabies that are high.”
Rick Rockliff, a spokesman for poppy producer Tasmanian Alkaloids, told the BBC that these wallaby incursions aren’t very common, although other animals have been spotted “acting unusually” in the poppies.
Australia is a major producer of raw materials for the painkiller industry, supplying around half of the world’s (legally-grown) opium. And, it seems, the main supplier for wallabies as well.
Bees on a binge
Bees keep the world turning, but that doesn’t seem to stop them from functional alcoholism.
The bee nervous system is similar enough to that of humans for alcohol to have similar effects on them. In fact, researchers sometimes use bee colonies as models to test out the effects of alcohol intoxication in humans and other vertebrates. For example, a team of researchers at Ohio State University routinely gives bees ethanol — drinking alcohol — to see how it affects them. Unsurprisingly, they found that it affected their flying, walking, and grooming.
“Alcohol affects bees and humans in similar ways — it impairs motor functioning along with learning and memory processing,” Dr Julie Mustard, an entomology researcher at the university, explained to the BBC.
But bees seem in no way content to limit their day-drinking to the lab. Just last year, Australian Parliament’s head beekeeper Cormac Farrell explained that the bees, which could be seen sometimes dropping on the ground around the Australian House of Parliament in Canberra, are just really blitzed. Sadly for the bees, they can sometimes drink themselves to death, and the queens aren’t very understanding of them — they will post guards at the entrance of their hives to keep any ‘merry’ bees from getting in.
“As the weather heats up, the nectar in some Australian flowers will ferment, making the foragers drunk,” Farrell told The Canberra Times last year. “Usually this makes them a bit wobbly, and if they come back to the beehive drunk the guards will turn them away until they sober up.”
“The drunk bees are kept out of the hive to stop the honey from fermenting inside, which could hurt the whole colony,” he added.
Only introduced and exotic honeybees seem affected, with Farrell noting that he had not seen any drunk native bees, of which Australia can boast 2000 species.
So, are bees just the victims of excellent work ethic and fermenting sugar? It doesn’t appear that way — bees just seem to enjoy getting smashed hard. Charles Abramson of Ohio State University told Newscientist that while most animals need to be coaxed into drinking alcohol, “we can get [bees] to drink pure ethanol, and I know of no organism that drinks pure ethanol – not even a college student.”
A bee, he adds, will drink the equivalent of a human downing 10 liters of wine in a single sitting. Flawless work ethic indeed!
Puff puff porpoise
Dolphins… like to pass toxic pufferfish around to get high.
The behavior was first reported on by marine biologist Lisa Steiner in 1995. She was studying a group of rough-toothed dolphins roughly in the region of the Azores when she noticed that some of them were pushing an inflated pufferfish around and rubbing their faces against it. Which was an odd sight, as that pufferfish uses one of the most lethal substances on Earth, tetrodotoxin, to protect itself from, among others, dolphins. Later on, Steiner would hypothesize that the dolphins were only exposed to tiny amounts of tetrodotoxin, and this resulted in a high, not death. Which is an ideal outcome in my book.
It’s still unclear whether the dolphins are actually getting a chemical kick out of the pufferfish or if they’re just harassing the poor animal for sport. The main points of contention are that tetrodotoxin isn’t known to cross the brain-blood barrier, and that it’s extremely deadly — one pufferfish contains enough to kill 30 full-grown people. However, in episode two of the BBC One documentary film, “Dolphins: Spy in the Pod,” a group of dolphins was filmed hunting pufferfish and biting into it but not eating it, then sharing the fish with their mates.
So this one is still a bit up in the air. But no matter whether the fish is used as a drug or a simple toy, given how toxic it is, it’s definitely dangerous.
These are a few of the more unusual stories of animals binging, but they’re certainly not the only ones. Jaguars like to chew on the roots of yagé vines — a main component of the hallucinogenic brew ayahuasca — and their diminutive cousins love catnip. And, well, humans are animals too. While it’s definitely a lot of fun reading about their shenanigans, hangovers aren’t, so enjoy your own real-life shenanigans in moderation.
Bottlenose dolphins also have a right-side bias, potentially even stronger than that of humans.
Almost all of us are right-handed, and bottlenose dolphins seem to share our preference. A 6-year study found that common bottlenose dolphins favor their right eye when foraging for food on the ocean floor. Most species of animals tend to favor one side of the body over the other. Kangaroos, cockatoos, orangutans, even horses show a general preference for the left side.
Handedness or laterality is believed to arise from the two-lobe structure of our brain. It’s estimated that for around 90% of us, our left brain hemisphere (this controls our right side) is in charge of processing language, making it the stronger and more dominant of the two. The right hemisphere generally handles visuospatial processing. “More than 95% of right-handed humans process language predominantly in the left hemisphere, while only approximately 70% of left-handed people [do the same],” the paper explains.
To get a better understanding of laterality in the common bottlenose dolphin (Tursiops truncatus), the team worked with a group of just under 30 individuals in The Bahamas. The team recorded the sounds and movements of these dolphins, especially as they were “crater feeding” — going nose-down to inspect the sand visually and with their echolocation.
Out of 709 pinwheel spins performed by several dozen dolphins, 705 steered were to the left, with the right eye used to look for a meal. The team says this indicates that the dolphins’ left hemisphere does most processing of prey-related sensory information, either of a visual nature or also involving echolocation.
The team notes that all four of the spins to the right were performed by the same individual — possibly an atypical dolphin whose brain is lateralized differently to the others. However, they remark that this dolphin had “an abnormally shaped right pectoral fin”.
Understanding how other brain regions specialize in various tasks in other species can help us learn more about how our brains work, and how they got to work like they do. In the case of dolphins, the team notes, anatomical asymmetry in the skull could also play a role in their lateral preference.
“Advances in non-invasive brain imaging techniques hold the potential to further explore the link between behavioural laterality and hemispheric specialisation and sensory and cognitive processing,” the researchers conclude.
This paper “Behavioural laterality in foraging bottlenose dolphins (Tursiops truncatus)” has been published in the journal Royal Society Open Science.
The bottlenose mother, pictured with her adoptive whale calf (which has a short and blunt beak compared to the dolphin’s long and slender beak) and biological daughter (bottom). Credit: Pamela Carzon.
Bottlenose dolphin mothers are some of the most caring and nurturing moms in the animal kingdom. For years, they will feed, protect, and play with their young. But what even knowing this couldn’t prepare researchers for this unusual behavior: a bottlenose dolphin was spotted caring for an orphan male calf which belongs to a different species and genus of dolphin.
Researchers observed the dolphin mother along the coast of French Polynesia, along with one of her biological calves and an adopted male calf, which was later identified as a melon-headed whale.
Adoption was once thought to be a uniquely human trait. Then, in 2006, primatologists at the University of São Paulo were astonished to find a group of capuchins that were caring for a baby marmoset. Along with the bottlenose dolphin (Tursiops truncatus) mother, these are the only two documented cases involving the adoption of an orphan from a different species and genus. Most other adoptions among wild animals — which are very uncommon, to begin with — occur between related members of the same species.
Researchers at the Groupe d’Étude des Mammifères Marins (GEMM) de Polynésie filmed the dual-species family from all angles as part of a broader project designed to study a pod of around 30 bottlenose dolphins, which first began in 2009. After the orphan melon-headed calf (Peponocephala electra) joined the mother and her biological calf, he rarely left her side. The researchers were amazed to see the three of them constantly swimming side by side, an unusual sight since dolphin mothers are known to care for only one young at a time.
What’s more, the adopted calf was also successful at integrating himself in the broader pod. Writing in the journal Ethology, the researchers in French Polynesia said that the melon-headed whale youngster is now behaving like a bottlenose dolphin, regularly surfing and leaping into the waves just like any other dolphin young.
The mother proved to be remarkably committed to her newly adopted calf. The researchers documented how the two were spotted constantly together for nearly three years until the melon-headed whale suddenly disappeared in April 2018 — that’s around the time he would wean. The union lasted far longer than that between the mother and her biological calf, which vanished at one-and-a-half years old. On at least two occasions, the mother was spotted nursing her adopted calf, which is a huge sign of investment. For mammals, making milk is a very costly process so sharing it with not only an unrelated individual but one belonging to an entirely different genus, is truly amazing.
But, if this behavior on the part of the dolphin momma is so costly, why did she go through all of it? One possible explanation is that the orphan calf triggered her maternal instincts. In other words, the calf was in the right place at the right time since the mother was already receptive to forming strong bonds with her own offspring. The dolphin mother also has an accommodating personality, being known for uncanny tolerance for scuba divers in the area.
Lastly, to make the story even more impressive, it seems the melon-headed whale calf himself may have played an important role in the union through sheer, brute determination.
“We argue that the primiparous foster mother’s inexperience and personality may have contributed to factors driving such non‐adaptive behavior. We also propose that the adoptee’s persistence in initiating and maintaining an association with the adult female bottlenose dolphin could have played a major role in the adoption’s ultimate success, as well as the persistence of this cross‐genus adoption after the disappearance of the biological offspring,” the authors argued in their study.
We’ve always known that dolphins are some of the coolest and smartest creatures in the sea. The similarities they share with humans are remarkable, and a new study highlights yet another striking similarity: dolphins form friendships based on shared interests, and they can form close bonds for years.
The findings, published in the Proceedings of the Royal Society B by an international team of researchers from the Universities of Bristol, Zurich and Western Australia adds even more insight into the social habits of dolphins.Image credits: NOAA.
The study followed the population of Indo-Pacific bottlenose dolphins in Shark Bay, a World Heritage area in Western Australia — the only location where dolphins have been observed using marine sponges as foraging tools. These “sponger” dolphins use the technique to forage for food in deeper waters by using the sponges to protect their noses as they hunt.
Using behavioral, genetic, and photographic data collected from 124 male dolphins during the winter months in Shark Bay from 2007 to 2015, the team analyzed a subset of 37 male dolphins, comprising 13 spongers and 24 non-spongers. They found that the spongers spent more time associating with fellow spongers than the non-spongers.
“Foraging with a sponge is a time-consuming and largely solitary activity so it was long thought incompatible with the needs of male dolphins in Shark Bay – to invest time in forming close alliances with other males,” says Dr Simon Allen, a co-author of the study and senior research associate at Bristol’s School of Biological Sciences. “This study suggests that, like their female counterparts and indeed like humans, male dolphins form social bonds based on shared interests.”
Bottlenose dolphin with a sponge in Shark Bay. Image credits: Simon Allen.
Most dolphin species live in pods consisting of two to thirty animals. Between these groups, they tend to show empathetic, cooperative and altruistic behaviors. It has also been found that dolphins can migrate between pods, creating a complex social network. Also proven is that dolphins can communicate with other cetaceans through sounds, clicks and songs. So, really, given dolphins history, the latest findings aren’t really that surprising.
“Male dolphins in Shark Bay exhibit a fascinating social system of nested alliance formation,” added Manuela Bizzozzero, lead author of the study at the University of Zurich. “These strong bonds between males can last for decades and are critical to each male’s mating success. We were very excited to discover alliances of spongers, dolphins forming close friendships with others with similar traits.”
The fact that dolphins not only use tools, but they form relationships based off of this tool usage, and these relationships resemble the ones in humans is yet another testament to how intelligent and socially advanced dolphins are.
For the first time, biologists have reported the sighting of a hybrid between a melon-headed whale and a rough-toothed dolphin, off the coast of Hawaii. Just don’t call it a ‘wholphin’, they say.
The hybrid, in the foreground, swimming next to a melon-headed whale near Kauai, Hawaii. Photograph: Kimberly A Wood/ Cascadia Research Collective.
Here’s the thing. The rough-toothed dolphin (Steno bredanensis) is a species of dolphin that enjoys deep warm and tropical waters around the world. The melon-headed whale (Peponocephala electra), despite its name, is also a dolphin. So while it is still a hybrid, it’s a dolphin-dolphin hybrid — not a dolphin-whale one.
“Calling it something like a wholphin doesn’t make any sense,” said one of authors of the study describing the hybrid, Robin Baird, a Hawaii research biologist with Washington state-based Cascadia Research Collective. “I think calling it a wholphin just confuses the situation more than it already is.”
The rather unfortunate name ‘wholphin’ has stuck around since the 1980s, when a hybrid between a false killer whale and an Atlantic bottle-nose dolphin was reported by Hawaii’s Sea Life Park. That hybrid, called Kekaimalu, still lives at the marine mammal park, and is fertile — she has given birth to a calf at least once. But Kekaimalu, like this newly-observed hybrid, is not a whale-dolphin hybrid because, despite the name, false killer whales (Pseudorca crassidens) are also dolphins, not whales. This is why most biologists are averse to using the term ‘wholphin’ although it has caught on, particularly in the media.
Its name aside, the sighting suggesting that the ocean is even more diverse than we thought, and gives researchers a push to look for other hybrids, Sea Life Park curator Jeff Pawloski said.
“I always thought they were out there in the wild existing—it only makes sense,” he said. “And to know she has cousins out there in the ocean is an amazing thing to know.”
At this point, it’s unclear how many such dolphin hybrids exist in the wild and barring chance sightings, it’s difficult to carry out a larger study of their occurrence. However, we do know that hybrids are more likely to appear when there’s a decline in the population in one of the parental species, so that’s a good place to start looking.
As for how this particular individual came to be, it seems likely that a melon-headed whale got separated from its group and ended up traveling with rough-toothed dolphins.
It’s important to note that this is not a new species — although hybridization can lead to the emergence of a new species, there’s no indication that this is the case here. Lone hybrids are most often reabsorbed into the genetic bank of one of the two species, or cannot reproduce themselves.
“That isn’t the case, although there are examples where hybridization has resulted in a new species,” Baird said. “There’s no evidence to suggest it’s leading toward anything like species formation.”
Dolphin behavior is often surprisingly human-like.
It’s already well known that male dolphins often form alliances with each other — sometimes lasting for a few decades. Now, researchers have found that dolphins use individual vocalizations to refer to each other. In other words, they have names.
“We found that male bottlenose dolphins that form long-term cooperative partnerships or alliances with one another retain individual vocal labels, or ‘names,’ which allows them to recognize many different friends and rivals in their social network,” says Stephanie King from the University of Western Australia. “Our work shows that these ‘names’ help males keep track of their many different relationships: who are their friends, who are their friend’s friends, and who are their competitors.”
[panel style=”panel-default” title=”Dolphin calls” footer=””]Here’s an example of the mentioned dolphin calls.
Credits: Stephanie King.[/panel]
King and her colleagues wanted to figure out how the dolphins were using vocalizations to address each other, so they recorded the dolphins’ vocalizations using underwater microphones and determined the individual vocal label used by each of the males. They compared vocalizations from different alliances and found that males in an alliance retain vocal labels that are quite distinct from one another.
“All bottlenose dolphins (male and female) have their own signature whistle, which is a unique identity signal somewhat comparable to a human name,” King told ZME Science. “Animals use these signature whistles to introduce themselves to others (broadcast their identity) and can copy another dolphin’s signature whistle as a means of addressing that specific individual. However, it was previously thought that male dolphins would converge on a shared signature whistle when they formed long-term cooperative partnerships/alliances with one another. This is because across the animal kingdom it is very common for pairs or groups of animals to make their calls more similar when they share strong social bonds. This can be seen in some parrots, bats, elephants and primates, and represents a means of advertising the strength of their relationships and their group membership. It was previously thought that allied male dolphins also shared an identity signal to advertise alliance membership. While this is true for pairs of allied male dolphins in Florida, USA, we found it was not the case for the male dolphins found in Shark Bay, Western Australia, who form multi-level alliances e.g. alliances within alliances where each alliance can comprise up to 14 males.”
This strongly suggests that dolphins in alliances give each other names, or at least refer to each other using name-like vocalizations. However, this is also in contrast to previous studies, which found that dolphins refer to each other using shared vocalizations as a way of advertising their membership to that partnership or group.
“With male bottlenose dolphins, it’s the opposite–each male retains a unique call, even though they develop incredibly strong bonds with one another,” King says. “Therefore, retaining individual ‘names’ is more important than sharing calls for male dolphins, allowing them to keep track of or maintain a fascinating social network of cooperative relationships.”
Interestingly, researchers also found no evidence of any genetic relatedness influencing signature whistle similarity between males. In other words, dolphins that were related didn’t necessarily have similar names. Most of the males in this study had signature whistles that were notably different from those of both first-order and second-order alliance partners.
Just like in early human populations, it seems that dolphins use individual vocal labels to maintain recognition within complex social structures. It’s not clear if this behavior is restricted only to bottlenose dolphins.
King and her colleagues now intend to study the dolphin interpersonal relationships even more closely. They want to record and then play the “names” of individual males back to the dolphin to see how different males would react to the call in different circumstances.
“It will be interesting to reveal whether all cooperative relationships within alliances are equal or not,” she says.
The bottlenose dolphin is the best-studied dolphin species, so researchers aren’t sure yet if this behavior also exists in other species — but it very well might. King explains:
“For pairs of males that form alliances in Florida, it appears they do make their identity signals more similar. Where there is only one partner, such convergence may be used to indicate commitment to one another, but we found that when multiple males form alliances between themselves and other alliances (e.g. multi-level alliances) then retaining individual names is more important than sharing calls as it allows dolphins to negotiate a complex social network of cooperative relationships. There may be other vocalisations that do not encode identity that might be favoured by particular alliances. That is something that would be worth investigating. The bottlenose dolphin is, so far, the best studied small dolphin species, but evidence suggests that other species,such as spotted dolphins and common dolphins, also have signature whistles.”
A new study sheds new light on a disturbing practice of global fisheries — the killing of aquatic mammals to use as bait. Common victims include dolphins, otters, seals, and even some endangered species. The practice has received very little attention from the international community, researchers say.
Bycatch is a well-known and studied problem. It represents the incidental capture of dolphins, sea turtles, birds and other non-targeted species in fishing operations. But there’s another problem with fishing: that of bait. According to a new systematic review, the problem is much more widespread and dramatic than most people realize.
The study reports that more than 40 species of aquatic mammals have been utilized as bait since 1970 in 33 or more countries. In at least one big fishery, 80% of these species were deliberately killed to be used as bait. For instance, shark fisheries routinely kill dolphins and use their parts as bait for sharks.
The study’s lead author, Dr. Vanessa J. Mintzer from the University of Florida, says that there is very little information about this practice and how much wildlife it affects.
“Killing for use as bait is a primary threat affecting Amazon river dolphins, known as botos — the species and issue I have studied since my Ph.D. dissertation. With this global review we wanted to see whether, and where, other species were killed for bait, and learn about possible solutions to stop the problem,” says Dr. Mintzer.
Of course, it makes a lot of sense that this practice is kept under the lid. Killing animals for bait is, essentially, a clandestine activity. Even if it is legal, no one’s going to advertise it. So it’s not really surprising that the data about this practice is sparse at best — but this needs to change, Mintzer says. We don’t know how much of an impact it has, how widespread it is, and, especially in ecosystem hotspots, how many endangered creatures it threatens.
“For scientists already working on species and locations identified as “hot spots” in this review, organized efforts should begin right away to estimate these numbers,” she says. “It took years to determine that the hunt for botos was unsustainable and now conservation actions need to be expedited. We need to identify other affected populations now to facilitate timely conservation actions.”
The study also urges authorities to take action. In many parts of the world, it’s not even illegal to kill marine mammals and use them as bait, and even where it is, not much action is taken to enforce this. Lastly, it’s up to the consumers as well as the local communities and businesses to push for sustainable fishery initiatives. Top-down implementation alone isn’t enough, we need to act on all levels of society. After all, how would you feel if you knew your meal was caught with dolphin or otter as bait?
The Amazon’s iconic freshwater dolphins are in steep decline, announced Brazilian researchers. According to them, the Amazon dolphin populations are halving every decade.
A majestic river dolphin leaping out of the water. Credit: F. da Silva VM.
There are two species of river dolphins living in the Amazon basin: the boto (Inia geoffrensis) and the tucuxi (Sotalia fluviatilis). The boto, also known as the pink river dolphin, is famous for its pink coloring, but many people aren’t aware that it actually comes in a large variety of shades. The dolphins first start off gray but turn pink as they age, with their final hue being influenced by behavior, capillary placement, diet, and light exposure.
Pink river dolphins can be found throughout much of the Amazon and Orinoco river basins in Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, and Venezuela. They are solitary creatures who are often seen alone or in small groups of 2-4 individuals. However, they’re not shy at all. Despite living in small, tight-knit groups, these dolphins can be incredibly curious and frequently interact with humans.
They’re also very agile. Unlike other dolphins, pink river dolphins have unfused vertebrae in their necks, which allow them to turn their heads 180 degrees, enabling the animals to maneuver around tree trunks, rocks, and other obstacles. They can also swim forward with one flipper while paddling backward with the other, letting them turn with more precision. Oh, and they’re also very brainy — they have, remarkably, 40% more brain capacity than humans.
The Amazon basin’s dolphins are considered to be relatively abundant, as far as freshwater cetaceans go. However, in recent years the animals’ numbers have declined due to dams that fragment populations but also other threats like the contamination of rivers and lakes, as well as human fishing.
In a new study published in the journal PLOS ONE, researchers at the Instituto Nacional de Pesquisas da Amazônia, Brazil, analyzed data from 22 years of surveys performed in the Mamirauá Reserve. The dolphins were surveyed by boat monthly from 1994 to 2017. During this time frame, the researchers found that both boto and tucuxi Amazonian dolphins have experienced a dramatic decline. At current rates, boto populations are halving every 10 years and tucuxi populations are halving every 9 years. These are some of the most severe rates of decline seen in cetaceans since the early days of modern whaling.
The researchers conclude that if the IUCN Red List criteria were applied to the findings, then both species would be classified as Critically Endangered. The river dolphins are already legally protected in the Amazon basin, but the authors of the new study call for greater enforcement of these laws. In 2006, the baiji or Chinese river dolphin was declared extinct. The baiji’s demise was rapid and shocking, going from a healthy population of some 6,000 animals to extinction in a few decades — nothing more than a blink of an eye.
“Without an indefinite extension and strict enforcement of this regulation, combined with observance of existing laws on gillnet use, the dolphins of the Amazon seem very likely to follow the freshwater dolphins of Asia on the path of extinction,” the authors concluded in their paper.
The game is the same whether you live on the ground or beneath the waves. A decade-long study has found that male dolphins employ complex pick-up strategies, including offering gifts and rallying wingmen.
Image credits: Mandy / Wiki Commons.
The complex social behavior of dolphins never ceases to amaze me. They hang out in cliques, they remember their friends even after decades apart, and are often more humane than we are. But being really smart doesn’t really prevent you from looking like a complete fool when you’re in love, it turns out.
In a study recently published in Scientific Reports, Australian and Swiss scientists report that male Australian humpback dolphins, Sousa sahulensis, go the extra mile when it comes to impressing the opposite sex. Specifically, they offer females gifts (large marine sponges, to be precise), carry out elaborate visual and acoustic displays, and rally wingmen to help their case.
“We were at first perplexed to witness these intriguing behavioural displays by male humpback dolphins, but as we undertook successive field trips over the years, the evidence mounted,” said lead author Dr. Simon Allen from UWA’s School of Biological Sciences.
“Here we have some of the most socially complex animals on the planet using sponges, not as a foraging tool, but as a gift, a display of his quality, or perhaps even as a threat in the behavioural contexts of socialising and mating.”
Researchers speculate that dolphins form temporary or permanent alliances, serving as wingmen for each other. They also act in seemingly silly ways, like carrying out the rooster strut, Allen says.
“The behavioral posturing by male Sousa is similar to that exhibited by bottlenose dolphins engaged in sexual displays in Shark Bay. The ‘rooster strut,’ for example, is performed by individual males or simultaneously by pairs of male in Shake Bay, where the head is arched above the surface and bobbed up and down, usually in the presence of a female.”
But the gift giving is even more impressive. Dolphins would dive to the seafloor and pluck large sea sponges, balancing them on the nose, presumably in a display of strength and agility — presenting themselves as suitable mates.
This type of strategy is rare in the non-human world but has been observed (to some extent) in other species. Male bowerbirds, for instance, toss colorful objects in the air to attract the attention of mates. But this is the first time dolphins or any other marine species has been observed to do so. It seems that study after study shows just how much we have in common with these intelligent creatures.
“This is a new finding for this species, and presents an exciting avenue for future research, Allen concludes.”
Journal Reference: S. J. Allen, S. L. King, M. Krützen & A. M. Brown. Multi-modal sexual displays in Australian humpback dolphins. doi:10.1038/s41598-017-13898-9
Humans aren’t unique in getting Alzheimer’s — Oxford researchers have found that dolphins can get both Alzheimer’s and Type 2 Diabetes. These diseases might be a consequence of longer lifespans.
At a first glance, few animals seem more different than humans and dolphins. We live on the ground, they live underwater. We have hands and feet, they have fins. But if you look a bit deeper, you start to see a lot of similarities. We’re both mammals with complex tight-knit social groups, we both use complex vocalizations, and we’re both quite intelligent. Now, researchers have found another aspect that strengthens that bond: degenerative disease.
Simon Lovestone, an old age psychiatrist from Oxford Health NHS Foundation Trust, carried out a review of previous studies to see how common it is for other animals to suffer from Alzheimer’s. He found no evidence of onset in any other species.
‘It is very rare to find signs of full-blown Alzheimer’s Disease in non-human brains,’ said Professor Lovestone, who also studies dementia for the National Institute for Health Research (NIHR). ‘This is the first time anyone has found such clear evidence of the protein plaques and tangles associated with Alzheimer’s Disease in the brain of a wild animal.’
Before Lovestone actually found evidence of Alzheimer’s in dolphins, he identified a potential predilection of the marine mammals towards the disease. Thankfully, he told the right people about it.
‘It was a moment of serendipity when I heard Simon give a talk about the possibility that dolphins might be predicted to get dementia, as our collaborators have previously worked with dolphins,’ said Professor Frank Gunn-Moore from the University of St Andrews.
Alzheimer’s “eats” from your brain. Image via Wikipedia.
Humans and dolphin have another, rather unusual, trait in common: we continue to live long after our fertility declines. Regardless of their overall lifespan, animals don’t tend to live long after their fertility declines. In a competitive environment, this makes a lot of sense: you can’t make more offspring, so your utility to the species is limited. But humans and dolphins are different. Both for men and women, fertility declines sharply after 40 years, but people can go on to live 100 and even more. A similar process happens to dolphins (and orcas).
In order to prove their theory, researchers analyzed the brains of dolphins washed ashore on the Spanish coast. They were specifically looking at ‘plaques’ of a protein called beta-amyloid in the brains of dolphins, as well as tangles of another protein called tau. These are the main signatures of Alzheimer’s disease, and both of them were identified in the washed dolphins. Researchers believe that the hormone called insulin is directly connected to this process. Insulin regulates levels of sugar in the blood and starts a complex cascade of chemical reactions which have a dramatic impact on the body. Mice studies, for instance, have shown that extreme calorie restriction affected insulin signaling, which in turn extended the lifespan of the mice by up to 300%. If this is the case in the cetaceans, then Alzheimer’s (and possibly diabetes) might be a result of living longer.
‘We think that in humans, the insulin signalling has evolved to work in a way similar to that artificially produced by giving a mouse very few calories’, says Professor Lovestone. ‘That has the effect of prolonging lifespan beyond the fertile years, but it also leaves us open to diabetes and Alzheimer’s Disease. Previous work shows that insulin resistance predicts the development of Alzheimer’s Disease in people, and people with diabetes are more likely to develop Alzheimer’s.’
‘But our study suggests that dolphins and orcas (who also have a long post fertility life span) are similar to humans in many ways; they have an insulin signalling system that makes them an interesting model of diabetes, and now we have shown that dolphin brains show signs of Alzheimer’s identical to those seen in people.’
Researchers still aren’t sure if dolphin Alzheimer’s manifests itself like in humans. Without studying dolphins in the wild, it’s impossible to say if they suffer from the same confusion and memory problems reported in Alzheimer’s patients. The team doesn’t advocate carrying out studies on captive dolphins.
However, this might also be important for developing new treatments for the disease. Treating it in the brain is very difficult early on, as there is little cerebral damage at this point, making it difficult to find a treatment target. But if the disease is connected to insulin signaling, then scientists could work on that, and develop a whole new avenue for Alzheimer’s treatment.
Ancient baleen ancestors had teeth as sharp as today’s lions which they used to slice prey to shreds, overturning long-held assumptions about baleen whale evolution. Modern baleen whales use a series of horny filtering combs that line the upper jaw.
Baleen whale ancestors had sharp teeth a new comparative-analysis suggests. Credit: Museums Victoria and Monash University .
At up to 29.9 metres (98 ft) in length and with a maximum recorded weight of 173 tonnes (190 short tons), the blue whale (Balaenoptera musculus) is the largest creature in Earth’s history. That may sound terrifying but this is a gentle giant whose diet consists almost exclusively of krill, a small oceanic creature that generally measures a measly 1-2 centimeters. It does eat copious amounts of it, consuming up to 40 million krill per day or 8,000 pounds simply by plowing the ocean with its bristle-like baleen structures that filter food from the water.
There are 12 baleen whale species divided into 4 families. However, there’s a second group known as the toothed whales (Odontoceti) since they use sharp teeth instead of baleen structures to catch prey. A prime example is the killer whales (Orcas Orca), which are actually dolphins.
[panel style=”panel-info” title=”Tooth whales don’t include ‘just’ whales” footer=””]Toothed whales make up one of two suborders within the cetacean species.
The term can be misleading since addition to whales the toothed whale suborder also consists of all species of dolphin and porpoise. [/panel]
From hunting to going for volume
A long-standing debate among scientists is when and how did baleen filter feeding appear. As early as Charles Darwin, scientists have speculated that baleen whale ancestors had teeth shaped like precursors to filter-feeding. But paleontologists at the Museums Victoria and Monash University reveal a different picture.
The team built 3-D digital models of ancient whale fossils and then compared them to modern mammals. They not only looked at modern whales but also four terrestrial extant species (lions, coyotes, pumas, and dingoes), as well as five seal species. That might seem like an odd analysis; after all, what do a lion and a humpback whale have in common? Not much, besides being both mammals, but the reality is scientists can learn a great deal about a species’ diet and feeding patterns judging from the size, orientation, and sharpness of teeth alone.
Tooth sharpness comparison between various ancient whales and modern carnivorous. Note the sharp cutting edges in the dingo and †Janjucetus. Credit: Carl Buell.
At the end of the day, the paleontologists surprisingly found that early whales such as Janjucetus, a 25-million-year-old species that co-existed with the forerunners of baleen whales, had teeth that were ‘optimized for slicing through flesh.’ In fact, they were just as sharp as today’s African lions!
This suggests that unlike today’s gentle giants, early whales looked like vicious predators.
“These results are the first to show that ancient baleen whales had extremely sharp teeth with one function—cutting the flesh of their prey,” Museums Victoria’s senior curator of vertebrate palaeontology Erich Fitzgerald said.
“Contrary to what many people thought, whales never used their teeth as a sieve, and instead evolved their signature filter feeding technique later—maybe after their teeth had already been lost.”
The baleen open question
In other words, ancient mysticeti — a term used to describe whales that feed using baleen — had teeth just as sharp and adapted for slicing meat as today’s most successful terrestrial predators and seals. They “never passed through a tooth-based filtration phase, and that the use of teeth and baleen in early whales was not functionally connected,” the authors wrote in the journal Biology Letters.
While the results are quite revealing, they still leave the important question of how baleen filtering appeared in the first place unanswered. One hypothesis suggests baleen filtering co-existed alongside raptorial teeth through a period of overlapping until the baleen strategy eventually won — or at least for some species. Another possibility is that some early mysticeti evolved into suction feeders which came with tooth loss.
More fossils might provide the missing link that bridges the answer to this yet open question. There is already good progress. In May 2017, we reported the discovery of the 36-million-year-old Mystacodon selenensis, which literally means ‘toothed whale’.
Wear on Mystacodon’s teeth tells us that this was a suction feeder who vacuumed up its prey instead of chomping it with its sharp teeth. Suction feeding — possibly an intermediate step toward the filter-feeding strategy we see today in baleen whales — is common among living marine mammals, including seals, dolphins and toothed whales, who use it either to capture prey or to prevent it from floating away while they swallow.
Some two million years ago, a third of the largest marine mammals went through a dramatic event that saw them being wiped out by an unknown event. This not only dramatically affected all marine biodiversity, but seemed to change the way entire ecosystems functioned.
Image via Wikipedia.
A team of scientists analyzed fossils of marine megafauna from the Pliocene and the Pleistocene epochs (5.3 million to around 9,700 years BC). While marine mammals were the most threatened, they weren’t the only ones. Extrapolating from the data, they concluded that a whopping 43% of all turtle species were lost, as well as 9% of shark species. Some 35% of birds also went extinct. All in all, marine mammals lost 55% of their diversity, never to recover it again, and this cascaded into other species in the ecosystem.
“We were able to show that around a third of marine megafauna disappeared about three to two million years ago. Therefore, the marine megafaunal communities that humans inherited were already altered and functioning at a diminished diversity”, explains lead author Dr. Catalina Pimiento, who conducted the study at the Paleontological Institute and Museum of the University of Zurich.
This wasn’t without consequence, and the entire ecosystem struggled to recover. Pimiento estimates that 17 percent of the total diversity of ecological functions in the ecosystem disappeared and 21 percent changed. Left without their preferred food source, common predators couldn’t adapt and went extinct, while new species emerged, challenging the older ones.
It’s not clear what triggered this extinction, but because large marine mammals were especially affected, researchers believe it was a climate change. Since this extinction wasn’t even known before, more research is needed before the cause can be identified with certainty.
“Our models have demonstrated that warm-blooded animals in particular were more likely to become extinct. For example, species of sea cows and baleen whales, as well as the giant shark Carcharocles megalodon disappeared”, explains Dr. Pimiento. “This study shows that marine megafauna were far more vulnerable to global environmental changes in the recent geological past than had previously been assumed”.
This draws significant similarities to today’s situation. Nowadays, climate is warming once again, but at a much faster rate than it did at any point in at least a few million years — because the cause isn’t natural, it’s anthropic. It’s us. Marine mammals such as dolphins and whales are once again under great threat due to climate change, and it’s quite possible that we’re once again headed for a great extinction.
Journal Reference: Catalina Pimiento, John N. Griffin, Christopher F. Clements, Daniele Silvestro, Sara Varela, Mark D. Uhen and Carlos Jaramillo. The Pliocene marine megafauna extinction and its impact on functional diversity. June 26, 2017. Nature Ecology & Evolution. DOI: 10.1038/s41559-017-0223-6.
In a saddening though not unforeseeable move, the Trump administration has taken another jab at the environmental protection laws in the US, throwing out a proposal to protect endangered whales and sea turtles — even though it was supported by the fishing industry.
A mother sperm whale and her calf. Image credits: Gabriel Barathieu.
Basically, the measure said that if too many protected species were being caught with gill nets, fishing with these drift nets would be stopped for up to two seasons. These nets can measure up to a mile (1.6 km) and often trap or injure numerous species, including endangered ones. Ironically, the industry members themselves proposed this measure, which only affected 20 fishing vessels.
Fin, humpback and sperm whales, short-fin pilot whales and common bottlenose dolphin, leatherback sea turtles, olive-ridley seat turtles and green sea turtles were heavily affected by the nets. The National Marine Fisheries Service, which under President Trump abandoned this measure, said that the fishing industry “has worked hard to reduce its impact” and that there was no need for such a protection scheme.
“Under the proposed regulations, caps would have been established for five marine mammal species and four sea turtle species,” the agency explained in a final action published in the Federal Register Monday afternoon. “When any of the caps were reached, the fishery would have been closed for the rest of the fishing season and possibly through the following season.”
Turtles can easily get trapped as by-catch in these nets. Image credits: NOAA.
The industry was taking efforts to follow this proposal even though it was only classified as “pending.” Michael Milstein, the spokesperson for the service, cited figures saying that by-catch has reduced substantially, but he was heavily contradicted by biologists and conservationists.
“The Trump administration has declared war on whales, dolphins, and turtles off the coast of California,” Todd Steiner, director of the California-based Turtle Island Restoration Network, told the Los Angeles Times. “This determination will only lead to more potential litigation and legislation involving this fishery. It’s not a good sign.”
Steiner also said that a lot of the by-catch reduction is not owed to the industry improving its practice, but to the sheer reduction of the fishing fleet.
According to NOAA data quoted by the nonprofit Center for Biological Diversity, the California-based gillnet fishery targeting swordfish “catches and discards more than 100 protected whales, dolphins, seals and sea lions each year, in addition to thousands of sharks and other fish.” Katherine Kilduff, an attorney with the Center for Biological Diversity, said that even though by-catch numbers are decreasing, gillnet fishery still injures a large number of endangered animals.
Considering the extremely low numbers of some populations, even a few wounded or killed turtles and whales could make a dramatic difference. The Pacific leatherback turtle, for instance, boasts no more than 2,300 adult females in the wild, each of which is important to the population.
The first study comparing the health of wild and captive dolphins found that the captives ones are much healthier. Wild dolphins are suffering greatly due to pollution, and are starting to carry diseases which could affect even humans.
Dolphins aren’t doing so well, and this is an alarm signal for all of us. Image credits: NASA.
When it comes to protecting the planet, we focus almost all our efforts on land even though most of it is covered by seas and oceans. The reasoning is pretty simple: we live on land, we don’t really see what’s happening in the water — even though scientists have a pretty good idea about the general in’s and out’s of the oceans, it’s hard to empathize in the same way. To put it bluntly, we don’t really care about the oceans, not as much as we should. For the most part, humanity has treated the oceans like a big sink (for carbon, plastic, and junk in general), and it’s starting to show.
As predators pretty high up the food chain, they tend to accumulate the pollution from all the ranks below them. Things get polluted, fish eat said things, and dolphins eat said fish, sucking all the pollution within. This is a general rule in ecosystems, predators tend to concentrate pollution — which is one of the reasons researchers wanted to study dolphins. Another couple of reasons is that they are mammals and they’re more similar to humans than the average fish, and we’ve been keeping them in captivity for long enough to conduct a relevant comparison.
Patricia Fair, a research professor at the Medical University of South Carolina and lead author of the study, says the immune systems of all wild dolphins they studied were “chronically activated” due to the unhealthy environments they were living in.
“This is likely a result of encountering and fighting off illness caused by pathogens, parasites and anthropogenic pollutants in the ocean that do not exist in closely managed zoological habitats,” she explained. “The key to a healthy immune system is a balance between being able to recognise harmful organisms and over-stimulation and this study demonstrates the importance of the environment in these responses.”
They focused their study on the coasts of Florida and South Carolina. Noticeably, dolphins living nearby the Indian River Lagoon in Florida were found with larger amounts of mercury inside, which is also worrying for humans in the area — who can accumulate mercury in a similar way. But that wasn’t even the worst area; dolphins living in the ocean near Charleston, South Carolina exhibited the worst symptoms.
“In humans, this type of prolonged smouldering inflammation is associated with cancer, auto immune disease, cardiovascular disease, and increased vulnerability to infectious disease,” he said.
Due to the environmental stress, the dolphins are also vulnerable to diseases. Previous studies have shown that a fungal skin disease is running rampant in populations of dolphins with suppressed immune systems, which could be potentially passed on to humans. Having a fungal and microbial flora is absolutely normal in all environments, but generally, the immune system of higher animals should be able to keep them under control — when this doesn’t happen, it’s a sign that they’re in trouble.
Doctor Gregory Bossart, a co-author of the study and chief veterinary officer at Georgia Aquarum, said that the implications of these chronic problems should not be underestimated, and commented on the severity of the response we are seeing.
“In humans, this type of prolonged smouldering inflammation is associated with cancer, autoimmune disease, cardiovascular disease, and increased vulnerability to infectious disease.”
He also warned that dolphins are a sentinel species, serving as a marker for the overall health of the oceans. At the moment, things are not looking good.
“These wild dolphins are trying to tell us something and we are not listening. As a sentinel species, dolphins are an important way to gauge the overall health of our oceans. If wild dolphins aren’t doing well, it could also indicate future impacts to ocean health and even our own health.”
Journal Reference: Patricia A. Fair , Adam M. Schaefer, Dorian S. Houser, Gregory D. Bossart, Tracy A. Romano, Cory D. Champagne, Jeffrey L. Stott, Charles D. Rice, Natasha White, John S. Reif — The environment as a driver of immune and endocrine responses in dolphins (Tursiops truncatus). https://doi.org/10.1371/journal.pone.0176202
A new study has found evidence of mourning behavior in more than six species of marine mammals. The animals have been seen clinging to the bodies of dead relatives or podmates, refusing to let go — a behavior similar to that of human grieving.
A mother orca with her dead newborn. Image credits Robin W. Baird/Cascadia Research
The most likely explanation behind the animals’ observed behavior is grief, the researchers believe. Barbara King, emeritus professor of anthropology at William & Mary in Williamsburg, Virginia, and author of the book How Animals Grieve, defines animal grief as emotional distress coupled with a disruption of usual behavior.
“They are mourning,” says study co-author Melissa Reggente, a biologist at the University of Milano-Bicocca in Italy. “They are in pain and stressed. They know something is wrong.”
There is previous evidence of a growing number of species that seem to be stricken with grief at the loss of a family member. Elephants will even return over time to the resting place of a dead companion. All this lends weight to the argument that animals feel emotions. Throwing their hat into the controversy, Reggente and her colleagues gathered reports (most of them yet unpublished) of grieving behavior in seven whale species, from sperm whales to spinner dolphins. Their study found that all of these species have been reported to keep company with their dead around the globe. They’re not just isolated cases, either.
“We found it is very common, and [there is] a worldwide distribution of this behavior,” Reggente says.
And the animals seem to understand exactly what they’re doing. In one case, researchers on a boat in the Red Sea watched an Indo-Pacific bottlenose dolphin push the badly decayed corpse of a smaller dolphin through the water. When they lassoed the dead body and begun towing it towards land to bury it, the adult swam alongside the body, occasionally touching it. It escorted it until the water became dangerously shallow, and remained just offshore long after the carcass had been taken away. The relationship between the two dolphins isn’t clear, but Reggente believes they were either mother and child or close kin.
This behavior is even more striking when you consider just how costly it is for the animals. Keeping vigil over a dead companion means that the animals don’t feed and aren’t interacting with other whales, putting it at risk of starvation or social exclusion.
On other occasions, the scientists did have clues about the relationship between the mourner and the dead animals. One female killer whale, known as L72, was seen off San Juan Island in Washington carrying a dead new-born in her mouth. L72 showed signs of recently having given birth, and the researchers observing it reported that it was likely due to have another.
“She was trying to keep the [dead] calf up at the surface the entire time, balancing it on top of her head,” says study co-author Robin Baird of Cascadia Research Collective in Olympia, Washington, who witnessed the mother’s efforts.
A killer whale mother and her offspring may spend their whole lives together, he adds. When one dies Baird believes that “the animals go through a period where they’re experiencing the same kind of emotions you or I would when a loved one dies.”
The study also found reports of whales holding dead calves in their mouths, pushing them through the water or touching them with their fins. Grieving can also involve a whole community of whales — in one case, short-finned pilot whales in the North Atlantic Ocean created a circle around one adult and dead calf, seemingly protecting them.
Another case involving spinner dolphins took place in the Red Sea. Here, one adult pushed a young animal’s body toward a boat, and when the vessel’s crew lifted the carcass on board, the entire group of dolphins nearby circled the boat and swam off.
“We cannot explain why they did this,” Reggente says.
“Sure, sometimes we may be seeing curiosity or exploration or nurturing behavior that just can’t be ‘turned off,’” King said. “[But] it’s undeniable that we can also read something of the animals’ grief in the energy they expend to carry or otherwise keep dead infants afloat, to touch the body repeatedly, to swim in a social phalanx surrounding the primary affected individual.”
This behavior certainly has an element of curiosity or remanent nurturing instincts behind it, but they can’t, by themselves, explain what we’re seeing these animals do. They expend a whole lot of energy, either individually or as a group, in their rituals of carrying or keeping dead individuals afloat. The social interaction, centered on supporting the grieving individual, is also highly reminiscent of human society when confronted with the loss of its members.
We all know the pain and harrowing loneliness of losing a loved one, and it seems whales do too. The question now is how will we treat these animals, knowing they feel the same way as we do.
The full paper, titled “Nurturant behavior toward dead conspecifics in free-ranging mammals: new records for odontocetes and a general review” has been published online in the Journal of Mammalogy and can be read here.
Maui’s dolphin or popoto is the world’s rarest and smallest known subspecies of dolphin.
The Maui dolphin is the world’s rarest, with under 60 individuals remaining in the wild – all in the waters around New Zealand. The area that was opened for exploration overlaps 3000 square kilometres into the sanctuary, including some large areas of the Tarnaki coast in the north island. However, the government doesn’t appear to be too worried.
“I think primarily once you go from exploration right through to production, you’re not jeopardising the wildlife,” says Minister of Energy and Resources Mr Bridges.
Of course, that’s not even remotely true. Even if it never gets to the extraction, just exploration can be very dangerous for marine wildlife. Seismic prospection lies at the very core of exploration; what happens is that specially equipped vessels carry one or more cables containing a series of hydrophones at constant intervals. These hydrophones record the acoustic waves coming from one or several sources, which are almost always airguns. The main problem is that marine seismic surveys have a high risk of disturbing, damaging or even killing marine wildlife, especially cetaceans as dolphins and whales which rely on sound to communicate with one another (and even to navigate).
It has been shown that several species of whales purposefully avoid their regular migratory and breeding grounds where seismic surveys are carried, despite claims coming from oil companies and fossil fuel associations. However, as it often happens, the importance of protecting wildlife fades in comparison to those black, oily dollars.
“There has been petroleum exploration in that area for a long period of time,” says Mr Bridges. “I think it’s about achieving a balance.”
An unprecedented image created by UK and US researchers shows how a submerged human is “seen” by dolphins through echolocation.
Echolocation, also called bio sonar, is the biological sonar used by several kinds of animals, including dolphins. Basically, they emit sounds around them and then listen to the returning echo to locate and identify different objects or creatures around them. For this experiment, a female dolphin named Amaya directed her sonar beams at a submerged diver, while hydrophones captured the ensuing echoes. To avoid added noise, the diver went in without a breathing device that could cause extra bubbles.
The team led by Jack Kassewitz of SpeakDolphin.com used an imaging system known as a Cymascope. The system makes it possible to record and store dolphin echolocation info and then create 2D images from those sounds. Computers can then, through models, improve this image and make it 3D.
“We’ve been working on dolphin communication for more than a decade,” noted Kassewitz in a release. “When we discovered that dolphins not exposed to the echolocation experiment could identify objects from recorded dolphin sounds with 92% accuracy, we began to look for a way for to see what was in those sounds.”
The results were so good they surprised even the researchers – for the first time, we get the chance to see what cetaceans “see” through echolocation.
“We were thrilled by the first successful print of a cube by the brilliant team at 3D Systems,” said Kassewitz. “But seeing the 3D print of a human being left us all speechless. For the first time ever, we may be holding in our hands a glimpse into what cetaceans see with sound. Nearly every experiment is bringing us more images with more detail.”
For the future, they plan to determine how dolphins share these images, through some kind of sono-pictorial languages (that uses both sounds and images). It would also be interesting to see how dolphins perceive these images, as it’s certain they don’t do it the same way as us.
Scientists from the Smithsonian have a surprising fossil dating about 6 million years old. The fossil seems to have been an ancestor of modern dolphins and might explain why dolphins left rivers and set out for the ocean.
3D printed reconstruction of the dolphin’s head. Image via Smithsonian.
Today, there are almost 40 species of dolphins, and all of them are intriguing animals. For starters, all dolphins are marine mammals, which in itself is pretty rare; they evolved from land mammals need to breathe air from the surface and their skeleton is still characteristic of land animals – not fish. The traditional theory of cetacean evolution (whales and dolphins) suggests that this happened sometime around 50 million years ago. But the interesting thing is that they initially lived in rivers, and only started inhabiting the oceans much later. They were also pretty successful from the start.
“Fossil evidence suggests that river dolphins’ ancestors were widespread around the globe,” the Smithsonian press release states. I. panamensis was one of these flourishing dolphin ancestors.
Today, there are only 4 species of river dolphins, and all of them are endangered… so what happened? Why were they so successful then, and not so much now? Which leads us to this fossil.
The fossil, which dates from 5.8–6.1 million years ago, was found on the Caribbean coast near the town of Piña, Panama. It consists of half a skull, lower jaw with an almost entire set of conical teeth, right shoulder blade and two small bones from the dolphin’s flipper.
“We discovered this new fossil in marine rocks, and many of the features of its skull and jaws point to it having been a marine inhabitant, like modern oceanic dolphins,” Nicholas D. Pysenson, curator of fossil marine mammals at the Smithsonian’s National Museum of Natural History and the lead author of the study, said in the release.
Scientists from the Smithsonian’s National Museum of Natural History and the Smithsonian Tropical Research Institute collect the fossils of Isthminia panamensis, a new fossil dolphin, from the Caribbean coast of Panama on 18 June 2011. The fossil is encased in a white plaster jacket, and recovered as the tide rushed in. Credit: Aaron O’Dea / Smithsonian Institution
This seems to be one of the earliest fossils which shows a marine dolphin, potentially capturing the species in a transition period.
“We discovered this new fossil in marine rocks, and many of the features of its skull and jaws point to it having been a marine inhabitant, like modern oceanic dolphins,” added Pyenson“Many other iconic freshwater species in the Amazon, such as manatees, turtles and stingrays have marine ancestors, but until now, the fossil record of river dolphins in this basin has not revealed much about their marine ancestry. Isthminia now gives us a clear boundary in geologic time for understanding when this lineage invaded Amazonia.”
Other fossilized animals found at the same site as Isthminia panamensis were marine species, further confirming that I. panamensis lived in a salty, marine environment.
“Isthminia is actually the closest relative of the living Amazon river dolphin,” said study co-author Aaron O’Dea, staff scientist at the Smithsonian Tropical Research Institute in Panama. “While whales and dolphins long ago evolved from terrestrial ancestors to fully marine mammals, river dolphins represent a reverse movement by returning inland to freshwater ecosystems. As such, fossil specimens may tell stories not just of the evolution these aquatic animals, but also of the changing geographies and ecosystems of the past.”
Because river dolphins are so threatened now, understanding the environmental constrains which made them leave rivers initially is more important than ever, as it may enable biologists to understand and set up better conservation plans.
Known to feed mainly on seals, the images Jon Aars at the Norwegian Polar Institute captured of a polar bear dining on dolphins is a “culinary” first for the species. The photographs were taken in the Norwegian High Arctic, mid-April 2014. The bear was seen feeding on the carcass of one white-beaked dolphin, and covering another with snow.
“It’s full of proteins” – Bear. Image via: huffingtonpost.com
“We think that he tried to cover the dolphin in snow in the hope that other bears, foxes or birds would have less of a chance of finding it. Maybe to be able to eat it a day or two later, once he had digested the first one,” said Aars.
Jon Aars published his findings in the June 1 issue of Polar Research, remarking that in the following ice-free summer and fall seasons they discovered another seven carcasses, believed to have been scavenged on by six bears.
“It is likely that new species are appearing in the diet of polar bears due to climate change because new species are finding their way north,” he told AFP.
Although they are a regular sight in the Norwegian Arctic during the summer when the ice has melted, they have never before been observed so far north during the other seasons, when the waters are still covered in ice.
Image via: straitstimes.com
But Norwegian scientists have reported two almost ice-free winters in recent years, which they believe could have attracted the mammals further north, and became trapped by dense ice blown into a fjord by strong north winds. Coupled with the strong retreat of ice all around the Arctic region, and with it, that of the seals that make up bears’ primary source of food, the dolphins were invited to dinner.
“They will eat any marine mammal given a chance,” Ian Stirling of the University of Alberta in Canada told New Scientist. “The bigger surprise was that the dolphins were entrapped before they could migrate south for the winter.”
Aars states that the bear likely used the same hunting techniques it used to catch seals, waiting for the animal to surface through a hole in the ice to breathe. “Even if they saw the bear, the dolphins did not necessarily have any other choice,” he said.
“I don’t think that this signifies a great upheaval” in the diet of the carnivores, said Aars. “It’s just that the polar bear is coming into contact with species they have not been used to meeting until now.”