Tag Archives: bats

Bats’ superpower: they innately know the speed of sound

Unlike birds that learn their songs or mammals that learn how to hunt, bats are born knowing how to make sound waves above human hearing to catch their prey, according to a new study. The researchers, surprised by the results, expect this to be the case in all bats, as brain structures are similar across species.

Bats are born with this knowledge, and it makes all the difference for them. Image credit: Flickr / Michael Pennav

To be able to find their prey in the dark and avoid crashing into trees, bats rely on a remarkable navigation system called echolocation. They produce sound waves above the human hearing that bounce off objects in the environment, and based on how the sound comes back to them, they can tell how near or how far they are to other objects. Their ears are fine-tuned to recognize their own calls.

Bats can estimate the position of the object based on the time that elapses between the moment the sound wave is produced and the moment it is returned to the bat. This calculation depends on the speed of sound, which can vary in different environmental conditions, such as air composition or temperature — and bats carry out this calculation instinctively.

Since this was discovered more than 80 years ago, researchers have been trying to figure out whether bats acquire the ability to measure the speed of sound over the course of their lifetime or are born with this innate and constant sense. Now, researchers from the Tel Aviv University in Israel have the answer.

Zoom in on bats

Eran Amichai and Yossi Yove did an experiment through which they manipulated the speed of sound. They trained eight adult Kuhl’s pipistrelle bats (Pipistrellus kuhlii) to fly to a perch within a chamber, enriching the air composition with helium to increase the speed of sound. Helium is less dense than other atmospheric gases so sound travels faster through it.

The researchers raised bat pups and adult bats under these conditions and neither were able to adjust to the new speed of sound. They consistently landed in front of the target, indicating that they perceived the target as being closer, which means they didn’t adjust their behavior to the higher speed of sound.

This happened both in the adult bats that had learned to fly in normal environmental conditions and in the pups that learned to fly in an environment with a higher-than-normal speed of sound. For the researchers, it means that the rate of the speed of sound in bats is innate, instead of learning it — they have a constant sense of it.

But that wasn’t the only conclusion of the study. The researchers found out that bats don’t actually calculate the distance to the target according to the speed of sound. As they don’t adjust the speed of sound encoded in their brains, they also don’t translate the time it takes for the sound waves to return into units of distance.

“Bats do not measure distance, but rather time, to orient themselves in space. This may sound like a semantic difference, but I think that it means that their spatial perception is fundamentally different than that of humans and other visual creatures, at least when they rely on sonar. It’s fascinating to see how diverse evolution is in the brain-computing strategies it produces,” Yovel said in a statement.

It’s mind-bending when you think about it, almost like a superpower. But then again, if you’re a mammal that flies and navigates using sound, developing superpowers is probably what you need to survive.

The study was published in the journal PNAS.

Extremely rare case of death from bat rabies in France

Most bats do not have rabies. According to the US Centers for Disease Control and Prevention (CDC), even among bats submitted for rabies testing, only about 6% had rabies. Rabies can only be confirmed in a laboratory but any bat that is active by day or is found in a place where bats are not usually seen like in your home or on your lawn or attic could be rabid. A bat that is weak and unable to fly could potentially be sick.

A man died of rabies in Limoges, in southwest central France, most probably after being bitten or scratched by a bat, as reported recently by the Institut Pasteur. This is a first in mainland France.  The sixty-year-old succumbed to encephalitis, an inflammation of the brain of unexplained origin, in August 2019. A partnership established between the Necker hospital and the Pasteur Institute, aimed at identifying the causes of undocumented encephalitis, led to the genetic analysis of post-mortem samples. These analyzes at Necker Hospital in Paris showed that he had contracted a lyssavirus, European Bat LyssaVirus type 1 (EBLV-1), sheltered by bats.

“This shows that there are cases of rabies that we can miss”

“It is thanks to this retrospective diagnosis that this case was brought to light. This shows that there are cases of rabies that can be missed, ” explained Laurent Dacheux, deputy head of the national reference center for rabies at the Institut Pasteur.

“The trace of this virus was identified at that time, in November 2020. In the midst of the coronavirus , and this discovery went unnoticed”, continues Laurent Dacheux. This exceptional case was finally mentioned in a popular science article on the Mesvaccins.net site and highlighted by the regional daily Le Populaire du Center .

In contact with bats

“It has been thirty-five years since a death of this type has occurred in the world. And in mainland France, this is indeed a first,” assures Laurent Dacheux.

In 2019, a 21-year-old man died of rabies after coming into contact with a bat on Vancouver Island in the Canadian province of British Columbia. Health official Bonnie Henry confirmed that the man came into contact with a rabid bat in mid-May, began showing symptoms six weeks later, and died in July 2019.

Why don’t people get the rabies vaccine? 

Rabies is a fatal disease. Each year, tens of thousands of people are successfully protected from developing rabies through vaccination after being bitten by an animal like a bat that may have rabies.

In some cases, people who died of rabies knew they were bitten by a bat. They did not go to a doctor to seek medical help because they were not aware that bats can have rabies and transmit it through a bite. In other cases, it is also possible that young children may not fully awaken due to the presence of a bat (or bite) or may not report a bite to their parents. Most bats have small teeth which may leave marks that can disappear quickly.

Which animals can be infected with rabies? 

Any mammal can contract rabies. Rabies is most often reported in mammals that tend to come in contact with humans or live near human settlements, including bats, raccoons, skunks, and foxes. Cases of rabies have also been reported in deers, woodchucks, mongoose, opossums, coyotes, wolves, and monkeys. Pets and domesticated animals that are mammals can easily get the disease if bitten by another animal that is already infected. Cases in pets and other domesticated animals have been reported in dogs, cats, cows, horses, and rabbits.

If you are bitten by an animal – or if infectious material (such as saliva) from an animal gets into your eyes, nose, mouth, or a wound – it is important to wash the affected area thoroughly with soap and water and get medical advice immediately. Whenever possible, the animal should be captured and sent to a laboratory for rabies testing.

Scientists sequence the genomes of six bat species for clues to their unique features

Myotis myotis (Greater mouse-eared bat), Credit: Olivier Farcy.

Bats are the only flying mammals in the animal kingdom — but that’s not all they’re known for. Bats have a number of quite extreme adaptations, such as echolocation, highly sensitive sensory perception, significant longevity for their size, resistance to cancer, and exceptional immunity to viral infections. In fact, the coronavirus that has caused the world to grind to a halt is believed to have evolved inside bats, before jumping into humans.

No doubt, bats are amazing creatures. Now, for the first time, researchers have sequenced the raw genetic material that contains the instructions for bats’ unique, superpower-like adaptations.

“Given these exquisite bat genomes, we can now better understand how bats tolerate viruses, slow down aging, and have evolved flight and echolocation. These genomes are the tools needed to identify the genetic solutions evolved in bats that ultimately could be harnessed to alleviate human aging and disease,” Emma Teeling, senior author of the new study and a researcher at the University College Dublin, said in a statement.

Teeling and colleagues affiliated with Bat1k, a global consortium of researchers on a mission to sequence the genomes of every one of the 14,210 living bat species, published a study today in which they describe the genomes of six bat species.

The genomes were highly accurately analyzed with state-of-the-art sequencing technology and are about 10 times more complete than any other bat genome published in the past.

“Using the latest DNA sequencing technologies and new computing methods for such data, we have 96-99% of each bat genome in chromosome level reconstructions – an unprecedented quality akin to for example the current human genome reference which is the result of over a decade of intensive “finishing” efforts. As such, these bat genomes provide a superb foundation for experimentation and evolutionary studies of bats’ fascinating abilities and physiological properties” Eugene Myers, senior author of the study and Director of Max Planck Institute of Molecular Cell Biology and Genetics, and the Center for Systems Biology, said in a statement.

The first six bat genomes that were sequenced part of the Bat1K global genome consortium belonged to the greater horseshoe bat (Rhinolophus ferrumequinum), the Egyptian fruit bat (Rousettus aegyptiacus), the pale spear-nosed bat (Phyllostomus discolor), the greater mouse-eared bat (Myotis myotis), the Kuhl’s pipistrelle (Pipistrellus kuhlii) and the velvety free-tailed bat (Molossus molossus). 

Their genetic blueprints were compared to 42 other mammals, which enabled the researchers to pinpoint the position of bats on the mammalian tree of life.

Rhinolophus ferrumequinum (Greater horseshoe bat), Credit: Daniel Whitby.

Due to their many unique quirks, the question of where bats fit in on the tree of life has always been unresolved. But using novel phylogenetic methods and molecular datasets, the evidence suggests that bats are most closely related to Ferreuungulata — a group of mammals that includes carnivores like dogs, cats, and seals, as well as pangolins, whales, and hoofed mammals. Not a very narrow definition seeing how bats and cows are on the same roster, but as more bat genomes are sequenced their taxonomy can be refined further.

The side-to-side comparison of different mammalian genomes also helped tease apart adaptations that are unique to bats through the loss and gain of certain genes.

For instance, the genes that enable bats’ famous echolocation were selected for in the ancestral branch of bats, suggesting this is an ancient trait in this group of mammals.

There was also evidence of gene loss and gain involved in immunity, particularly the expression of antiviral APOBEC3 genes. This may explain why bats have exceptional immunity that makes them extremely tolerant to viral infections.

In this day and age, understanding the molecular mechanisms that allow bats to withstand coronaviruses may lead to new approaches, therapies, and vaccines meant to increase human survivability in the face of COVID-19.

“Having such complete genomes allowed us to identify regulatory regions that control gene expression that are unique to bats. Importantly we were able to validate unique bat microRNAs in the lab to show their consequences for gene regulation. In the future we can use these genomes to understand how regulatory regions and epigenomics contributed to the extraordinary adaptations we see in bats.” Sonja Vernes, Co-Founding Director Bat 1K, Max Planck Institute for Psycholinguistics, Nijmegen, Senior Author

Although the researchers sequenced the genomes of only six bats, they’ve already learned quite a lot. However, this is merely the beginning — there are still more than 1,400 known bat species to go.

The findings appeared in the journal Nature.

Bats can get coronavirus without getting sick, and here’s why

Coronaviruses that cause severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) are speculated to have originated in bats. But the mechanisms by which these viruses are maintained viable in individuals and bats remain an enigma.

Credit Wikipedia Commons

A research team from the University of Saskatchewan (USask) in Canada has just uncovered how bats can carry MERS coronavirus without getting sick—a finding that could shed light on how coronaviruses make the jump to humans and other animals.

“The bats don’t get rid of the virus and yet don’t get sick. We wanted to understand why the MERS virus doesn’t shut down the bat immune responses as it does in humans,” said USask microbiologist Vikram Misra in a statement.

The team demonstrated in their research for the first time that cells from an insect-eating brown bat can be persistently infected with MERS coronavirus for months, due to important adaptations from both the bat and the virus working together.

“Instead of killing bat cells as the virus does with human cells, the MERS coronavirus enters a long-term relationship with the host, maintained by the bat’s unique ‘super’ immune system,” said Misra, co-author. “SARS-CoV-2 (the virus that causes COVID-19) is thought to operate in the same way.”

Misra said the team’s work suggests that stresses on bats—such as wet markets, other diseases, and possibly habitat loss—may have a role in coronavirus spilling over to other species.

“When a bat experiences stress to their immune system, it disrupts this immune system-virus balance and allows the virus to multiply,” he said.

The research was carried out at USask’s Vaccine and Infectious Disease Organization-International Vaccine Centre (VIDO-InterVac), one of the world’s largest containment Level 3 research facilities, by a team of researchers from USask’s Western College of Veterinary Medicine and VIDO-InterVac.

“We see that the MERS coronavirus can very quickly adapt itself to a particular niche, and although we do not completely understand what is going on, this demonstrates how coronaviruses are able to jump from species to species so effortlessly,” said VIDO-InterVac scientist Darryl Falzarano, co-author of the study.

So far, the SARS-CoV-2 virus has infected more than 3.5 million people worldwide and killed 7% of those who tested positive. In contrast, the MERS virus infected nearly 2,500 people in 2012 but killed one in every three people infected. There is no vaccine for either SARS-CoV-2 or MERS.

Experts still aren’t sure what is the actual origin of the current COVID-19 pandemic. Since the virus is so similar to other viruses found in bats, it is likely that that’s where it originated, but so far, no smoking gun has been found yet. In order to confirm this theory, researchers need to isolate a live virus in a suspected species to correctly prove the source, and this hasn’t been done just yet.

The study was published in the journal Nature.

Six new types of coronavirus found in bats in Myanmar

While experts and governments are still trying to find the true origin of the current COVID-19 pandemic, a group of researchers studying bats in Myanmar discovered six new types of coronavirus — unrelated to the pandemic-causing SARS-CoV-2.

The finding could help to understand the relevance of coronaviruses in bats and know more about the viruses in general.

Credit Flickr

Historically, bats have been linked to highly pathogenic viruses that can pose a serious threat to human health if happen to make the jump to humans. This was the case with the severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS) that recently emerged. Nevertheless, the newly discovered viruses are not closely related to SARS, MERS or even the COVID-19, according to the researchers, which will now work to evaluate their risk to human health.

Experts still aren’t sure what is the actual origin of the current COVID-19 pandemic. Since the virus is so similar to other viruses found in bats, it is likely that that’s where it originated, but so far, no smoking gun has been found yet. In order to confirm this theory, researchers need to isolate a live virus in a suspected species to correctly prove the source, and this hasn’t been done just yet.

Due to their capacity to fly, bats can move in large numbers from different areas and host diverse pathogens. They are increasingly recognized by researchers as the natural reservoirs of viruses of public health concerns such as SARS and MERS.

“Viral pandemics remind us how closely human health is connected to the health of wildlife and the environment,” said Marc Valitutto, lead author, in a statement. “Worldwide, humans are interacting with wildlife with increasing frequency, so the more we understand about these viruses in animals the better we can reduce their pandemic potential.”

The research was done through a project called PREDICT, focused on discovering and understanding better pathogens that could spread from animals to humans. The team detected the new viruses thanks to the biosurveillance of animals and people.

Valitutto and his team specifically chose Myanmar as a research destination, as humans are in contact with local wildlife because of recent changes in land use and development.

The researchers collected over 750 samples of saliva and feces from bats in the area from 2016 to 2018. The following step was comparing the samples collected to already known coronaviruses, identifying the new six viruses.

They also found a coronavirus that had previously been discovered in Southeast Asia but not in Myanmar.

The researchers estimate that there are thousands of coronaviruses more that could be found in bats. That’s why they believe the results will be highly important for future studies on bats across the world, hoping to understand better the potential of viral threats to humans.

Nevertheless, the importance of bats to ecosystems and human communities while being the natural reservoirs of many zoonotic pathogens presents a challenge for disease control. Bats provide critical services such as seed dispersal and pollination.

“Many coronaviruses may not pose a risk to people, but when we identify these diseases early on in animals, at the source, we have a valuable opportunity to investigate the potential threat,” said Suzan Murray, co-author of the study, in a statement. “Vigilant surveillance, research and education are the best tools we have to prevent pandemics before they occur.”

The study was published in the journal PLOS ONE.

Birds and bats have very weird gut bacteria, and it’s likely linked to flying

Bats and birds don’t seem to need gut bacteria the way other animals do, a new study finds.

Our microbiota or microflora — communities of bacteria making home in our digestive tract — play quite a central role in our health and wellbeing. These tiny helpers aid us in fighting bad bacteria and aid digestion. It’s not just us. Most vertebrates rely on similar bacterial communities for the same tasks.

A phylosymbiosis tree diagram showing a microbiome composition in bats and birds (marked with black bars) compared to other mammalian species.
Image credits Se Jin Song et al., (2020), mBio.

But not birds and bats, a new study found. By drawing on field samples and museum specimens, a team of US researchers has compared the makeup of mammal, bird, reptile, and amphibian microbiota, finding that species which evolved for flight tend not to rely on symbiotic bacteria almost at all.

You can’t fly with us

“If you’re carrying a lot of bacteria in your gut, it can be pretty heavy and may take resources away from you,” says Holly Lutz, a research associate at Chicago’s Field Museum and postdoctoral researcher at the University of California San Diego and co-author of the study.

“So if you’re an animal that has really high energetic demands, say because you’re flying, you may not be able to afford to carry all those bacteria around, and you may not be able to afford to feed them or deal with them.”

The study is the first of its kind and the first to showcase how different the microbiota of flight-capable species are compared to those of other vertebrates. The team believes that the necessities of flight are exactly what caused this difference in gut bacteria.

To the best of our knowledge, animals that are closely related to each other have similar gut microbiomes, because they evolved together — a pattern referred to by scientists as phylosymbiosis. Thus, Se Jin Song, the paper’s co-first author from UC San Diego, says that before the study the team assumed they would “see similar associations between animals and their gut microbes when the animals shared a similar diet.”

“Our pie-in-the-sky idea was that flight could impose a similar type of selection on which microbes animals host,” he explains. “What was shocking was that we didn’t find that birds and bats share a similar microbiome per se, but rather that both lack a specific relationship with microbes.”

For the study, the team analyzed fecal samples from roughly 900 species of vertebrates on a global scale. Researchers, museum collections, and zoo directors from around the world participated in the efforts, which ranged from zoo work to venturing deep into remote Ugandan and Kenyan caves with a flashlight to collect samples from African bats.

An African fruit bat.
Image via Pixabay.

After collecting the needed material, the team used high throughput genetic sequencing to process them. In essence, they extracted all DNA from all the samples, and then used individual genes to sift through the bacterial communities within each sample. For the final step, they pooled all of the data together to form the comparisons between species.

The microbiomes of bats and birds didn’t fit in with the rest of the vertebrates, the team found. While their gut bacteria makeup was quite similar, they had very little in common with other vertebrates. The team believes that it’s their shared lifestyle, not their ancestry (bats and birds are only very distantly related), that shapes their gut flora. In other words, their ability to fly.

Both groups evolved this ability independently, but no matter which way you cut it, flying is very energy-intensive and requires a light body. Bats and birds both have much shorter digestive tracts than comparable land mammals, and they both carry fewer bacteria, which likely helps reduce weight. The authors write that it’s also possible that diet plays a role here; due to the huge energy requirements of active flight, there may simply not be enough food to spare to maintain a symbiotic relationship with the bacteria.

Another important finding is that the few bacteria that do live in the digestive tract of both birds and bats tend to be very varied. Various types of individual bacteria live in the guts of different species of bats or birds, most other groups of amphibians, reptiles, and mammals apart from bats follow specific patterns.

“It’s almost like they’re just picking up whatever’s around them and they don’t really need their microbes to help them in ways that we do,” says Lutz.

“If we ever are putting ourselves in some kind of extreme situation where we’re disrupting our microbiome, there is something that we can learn from animals that don’t need their microbiomes as much.”

Lutz notes that this study wouldn’t have been possible without museum collections from around the world. Specimens of bird and bat kept in cryogenic chambers in the Field Museum’s Collections Resource Center were pulled out to help provide the broad samples needed for a study of this size.

“The scope of this paper —in terms of species that we sampled— is really remarkable. The diversity of collaborators that came together to make this study happen shows how much we can achieve when we reach out and have these big and inter-institutional collaborations,” says Lutz.

The paper “Comparative Analyses of Vertebrate Gut Microbiomes Reveal Convergence between Birds and Bats” has been published in the journal mBio.

Tasty moths try to evade predators — unappetizing moths don’t really bother

A new study suggests that plump, palatable moths will employ evasive maneuvers when under attack by a predator — but the less appealing ones won’t.

A great tiger moth (Arctia caja).

While running away from predators might seem — quite literally, sometimes — a knee-jerk reaction, not all animals behave this way. Further muddying the waters, not all species, even if closely related, behave the same way. So, why is that?

A new study looking into the predator-prey relationship between bats and moths suggests that less appetizing moths are more nonchalant when attacked by bats, whereas more palatable moths tend to employ evasive maneuvers. The work sheds light on the intricacies and complexities of anti-predator strategies in the wild, as well as their associated risks and rewards.

I’m a treat

Moths employ several layers of defense against potential predators. The most straightforward one is simply don’t be seen (by using camouflage) and don’t get caught (performing swoops and dives during a chase). They also employ chemical compounds that make them less appealing to predators and ultrasonic hearing (so they can hear bats on the prowl).

However, we know precious little about how these factors intertwine, and how they vary between different species of moths. A new paper led by Dr. Nicolas Dowdy of the Milwaukee Public Museum and Wake Forest University notest that certain species of tiger moths behave very strangely when attacked by predatory bats — they’re almost entirely unfazed.

In order to understand why, Dowdy and his team collected specimens from five different tiger moth species and released them in an outdoor “flight arena” at night, where wild bats would frequently swoop in to feed. The interactions were recorded using infrared cameras so that the team could track the behavior of each species during a bat attack. In order to quantify how appealing individual moths were, they tracked whether the bats ate them or spat them out.

The team’s hypothesis was that more carefree moths had chemical defenses in place to make them less ‘tasty’ for predators. Because of this, they would have less incentive to engage in evasive behavior when around bats, as their main defense relied on those chemical compounds. On the other hand, moths that lack these chemical armor — making them more ‘delicious’ — need to rely solely on the efficiency of their evasive maneuvers.

The team explains that there is a cost to engaging in anti-predatory behavior, such as evasive flying. A panicked moth might swerve at the last minute and avoid a bat, but that same risky maneuver costs energy, and may even land it in a spider web, or simply takes it away from food or a mate. Moths that do employ chemical defenses, the team believed, take the approach of not dodging bats because, in effect, it’s safer and ‘cheaper’ (energetically-speaking) than trying to fly out of the way.

“Strikingly, we observed that moths with weak or no chemical defenses often dive away to escape bat attacks,” explained Dowdy. “However, moths with more potent chemical defenses are more ‘nonchalant’, performing evasive maneuvers less often.”

By the end of the experiment, the team could reliably predict whether a particular moth would engage in evasive or nonchalant behavior in the arena based on their palatability. They say this mechanism likely functions in other species as well. Another exciting possibility is that the study can be used to reconstruct the behaviors or rare or even extinct species, the team explains.

By measuring levels of chemical defenses in a preserved specimen (i.e. compounds that made it un-tasty), they can reconstruct a species’ palatability. And, based on that, the team can estimate whether the species was active or lazier in its effort to evade predators.

So if you ever find yourself in the savannah staring down a lion, try your best to look deeply unsatisfying. And definitely don’t sprinkle catnip all over you.

The paper “Nonchalant Flight in Tiger Moths (Erebidae: Arctiinae) Is Correlated With Unpalatability” has been published in the journal Frontiers in Ecology and Evolution.

Vampire bats make friends in captivity — and keep them after release

A new study looking into social bonding dynamics for vampire bats reports that friendships they make in captivity are likely to continue after the animals are released back into the wild.

A tagged Desmodus rotundus bat in the wild.
Image credits Sherri ad Brock Fenton.

While primates are the most iconic group of animals when it comes to social dynamics and friendships, the new study suggests that vampire bats (Desmodus rotundus) also form cooperative relationships reminiscent of friendship. The findings also show that social interactions among vampire bats observed in the lab aren’t just a product of them being kept in captivity.

Life’s bat-er with friends

“The social relationships in vampire bats that we have been observing in captivity are pretty robust to changes in the social and physical environment–even when our captive groups consist of a fairly random sample of bats from a wild colony,” said Simon Ripperger of the Museum für Naturkunde, Leibniz-Institute for Evolution and Biodiversity Science in Berlin, the study’s lead author.

“When we released these bats back into their wild colony, they chose to associate with the same individuals that were their cooperation partners during their time in captivity.”

Together with co-lead author Gerald Carter of The Ohio State University, who has been studying vampire bat social relationships in captivity since 2010, Ripperger wanted to see if relationships the bats established in captivity would survive after release to the wild. The idea, boiled down, was to see if the partnerships these bats would form in the lab were ‘genuine’ or simply the best available at the time (in which case they would break down as the bats started to associate with other individuals).

All in all, the team reports, social interactions in the lab aren’t just an artifact of captivity. Not all relationships formed in captivity survived after release, the team reports. Similar to the human experience, however, cooperative relationships among vampire bats appear to result from a combination of social preferences together with external environment influences or circumstances, the team explains.

For the study, the team needed to record social interactions and networks among wild bats at much better resolutions than before. So, they enlisted the help of colleagues in electrical engineering and computer sciences to develop novel proximity sensors. Lighter than a penny, the new sensors could be carried by the bats without too much hassle and allowed the team to monitor entire social groups with updates a few seconds apart. The final step was to incorporate these observations with data on bat relationships from the lab.

The data showed that reciprocal grooming and food sharing among female bats in captivity (data recorded over 22 months) was a good predictor of whom these females would later interact with in the wild. The researchers report that the findings are consistent with the idea that both partner fidelity and partner switching play a role in regulating the bats’ relationships. In the future, the team wants to gauge how individual differences among bats influence these types of cooperation relationships. They also plan to look into social foraging and whether bats that cooperate within their day roost also go hunting together at night.

“Our finding adds to a growing body of evidence that vampire bats form social bonds that are similar to the friendships we see in some primates,” Carter said. “Studying animal relationships can be a source of inspiration and insight for understanding the stability of human friendships.”

The paper “Vampire bats that cooperate in the lab maintain their social networks in the wild” has been published in the journal Current Biology.

Drone landing gear.

New research plans to keep drones in the air longer by giving them the ability to land

An international team wants to make drones fly for longer — by teaching them how to land.

Drone landing gear.

Examples of various perching and resting actions.
Image credits Hang et al., (2019), Sci. Robot.

Drones today are really awesome gadgets, but they’re still severely limited by their short flight time. Despite a lot of effort being expended into improving their batteries or energy efficiency, drones can still only last minutes in the air.

Now, a new study reports that we don’t need bigger, better batteries to keep drones aloft for longer; it’s as simple as sticking landing gears on them.

Take a breather

The team says they’ve taken inspiration from birds, bats, and their impressive biological landing gears.

Many birds fly in short bursts and perch on elevated positions between bouts, they explain. By taking these elevated positions, they are able to conserve energy while keeping tabs on their surroundings for food or threats. Bats fly in a similar manner, but instead of perching, they simply hang upside down.

So the researchers set to work on incorporating similar abilities into our drones. The design they came up is reminiscent of a hawk’s talons. Drones equipped with this landing gear can land on flat or semi-flat surfaces like a bird, or perform a leaning landing on objects such as window sills.

An Xbox One Kinect sensor built into the design allows drones to automatically find and navigate perches, the team adds. After landing, the drone can turn down its rotors, thus saving battery power and prolonging its ability to fly. Other onboard devices such as cameras can be kept operational, allowing landed drones to keep performing their intended tasks.

 

The landing gear has only been tested under laboratory conditions so far. Although the results are encouraging, the team says they still need to tweak their design further to get the drones to land and take off autonomously. With some more work, however, they’re confident we’ll soon see drones perching atop buildings and other high surfaces.

The paper “Perching and resting—A paradigm for UAV maneuvering with modularized landing gears” has been published in the journal Science Robotics.

New Bombali Ebola Virus Found in Bats

Credit: Public Domain.

Credit: Public Domain.

Scientists have discovered a new Ebola virus called Bombali. No, there is no outbreak; this new species was identified before it could reach humans.

Bombali is not a portmanteau of Bombay and Bali; it is a novel virus in bats in Sierra Leone named after a district in the north of the country where it was found. This was two years after the end of an outbreak that infected over 29,000 people and killed over 11,300 across West Africa. The West African outbreak was caused by the Zaire species, which has so far been the most lethal in humans since it was first discovered in 1976.

Credit: Public Domain.

The sequencing of the complete genome of the novel Bombali species was published recently in the journal of Nature Microbiology. The Sierra Leone government announced this earlier in July.

The new Ebola species was discovered by the PREDICT Ebola Host project composed of scientists from the University of California Davis’s One Health Institute and Columbia University’s Center for Infection and Immunity, who were working with the government of Sierra Leone and the University of Makeni and Metabiota.

PREDICT predicting potential pathogenic threats.

PREDICT is a partnership between USAID, the EcoHealth Alliance, Metabiota, the Wildlife Conservation Society, and the Smithsonian Institution which enables global surveillance for pathogens that have the potential to spill over from animal hosts to people. The Bombali virus has the potential to infect human cells, but at the moment, it is unknown if the virus has already caused human infection or is harmful to humans.

“Identifying new viruses like Bombali in wildlife and testing their capacity for human infection can enhance our understanding of the pre-emergent viral diversity circulating in animals,” said Professor Simon Anthony, a virologist at Columbia University’s Mailman School of Public Health and co-author of the publication. “We want to discover viruses that have the genetic prerequisites for human infection and then prioritize them for further study and intervention.”

Bats Likely Hosts of Ebola Viruses

Bats can reportedly eat up to 1000 mosquitoes an hour. Photo via PD-USGov.

Before the discovery of Bombali, five Ebola virus species had been identified in previous publications. Bombali Ebola is different from the Zaire Ebola, which killed thousands of people between 2013 and 2016. Despite more than 40 years of research, the reservoir hosts for these viruses is still unknown.

The discovery of Bombali adds to growing evidence that bats are the likely hosts of these viruses. It was also recently discovered that bats seem to be the perfect hosts for many viruses.

Relax. Do Not Kill or Stress Out the Bats

Scientists emphasize that people should not try to exterminate or eradicate bats in response to this new discovery.  When bats are under a lot of stress from humans, healthy bats grow weak and become more susceptible to getting infected with viruses and can then spread Ebola to other places as they flee their habitats. Furthermore, bats eat night-flying insects, including many agricultural pests. As one of the major predators of night-flying insects, bats play an important role in controlling insect populations, helping to control pests that are able to transmit diseases and destroy crops. More than a quarter of currently-known bat species feed on fruit or nectar, pollinating many plants and dispersing seeds in the process.

Reduce Exposure to Reduce Risk of Infection

So, what do we do to prevent potential outbreaks of bat viruses? Bats infected with Bombali virus are not known to show signs of illness but they can shed the virus in their feces and saliva. People are advised to avoid contact with the urine or feces of bats. Researchers are working with communities living near the areas where Bombali Ebola-infected bats live to know more about this new species, study the interactions between bats and humans, and educate the communities on how to live safely with bats by reducing their risk of exposure to the virus.

What Makes Bats The Perfect Hosts For So Many Viruses?

Bats have been known to host up to 137 different kinds of viruses. Photo via PD-USGov.

 

Bats are mammals that have forelimbs adapted as wings; as such, they are the only mammals that are naturally capable of sustained flight. Bats are often associated with horror stories, vampires and haunted houses. For the most part, these creatures are misunderstood. Other than being the only mammal that can fly, bats are the perfect hosts for a lot of disease-causing viruses. Bats have been known to carry rabies, Hendra and Marburg viruses, and research has also suggested that bats may be the original hosts of Ebola and Nipah.

The Marburg virus and some strains of the Ebola virus can kill up to 90% of humans infected. India’s Kerala state has just faced an outbreak of the Nipah virus and seventeen people have died so far. This may seem like a small number, but only one of the eighteen people infected survived. For a number of these viruses hosted by bats, there is no known cure or vaccine, which means that doctors can only offer supportive treatment while the patient’s immune system fights off the virus.

When it comes to carrying viruses that can be transferred to other species including humans (so-called “zoonotic” viruses), bats are in a league of their own. These flying mammals host over 60 zoonotic viruses. This is rivaled only by rodents that carry a wide range of bacteria, viruses, protozoa, and helminths (worms).

Researchers compiled and analyzed databases of every virus identified in bats and rodents. They found that rodents host 179 viruses, 68 of which are zoonotic, while bats carry 61 zoonotic viruses, with 137 viruses in total. So, rodents win by a slight margin in carrying more human-infecting viruses, but bats host more zoonotic viruses per species — on average, each species of bat hosts 1.8 zoonotic viruses, while rodents host 1.48 viruses per species.

Humans have started creeping into areas where bats naturally live, especially in the tropics, which has led to an increased risk of contact with these animals. In Malaysia, for instance, commercial pig farms were installed in bat-inhabited forests which consequently led to the first human outbreak of Nipah, via pigs. As people continue to move into jungles on the planet, they will see more and more outbreaks of zoonotic viruses.

Bats also carry more human pathogens than other animals. Why? Because bats prefer to live close to one another (like humans spreading respiratory viruses like the flu during winter), giving plenty of opportunities for pathogens to spread between the bats.

But why aren’t these lethal viruses deadly for the bats? Scientists theorize that it has something to do with their ability to fly. It takes a lot of energy to fly and when a lot of energy is being utilized, a lot of waste is produced. To prevent this from damaging the DNA of bats, they have over time evolved a sophisticated defense mechanism that also helps prevent them from succumbing to disease. But what is this mechanism that prevents bats from getting sick from the unusually high microbial loads in their bodies? The question has finally been answered by Peng Zhou and colleagues in a paper published in the journal Cell Host & Microbe. Zhou and scientists at the Wuhan Institute of Virology in China found that in bats, an antiviral immune pathway called the STING-interferon pathway is dampened, and bats can maintain just enough defenses against illness without triggering the immune systems from going into overdrive. In humans and other mammals, an immune-based over-response to one of these and other pathogenic viruses can trigger severe illness. For example, in humans, an activated STING pathway is linked with severe autoimmune diseases.

Researchers at the University College Dublin have also shown that bat macrophages can rapidly mount a robust antiviral response whenever a pathogen is detected, but compared to the immune response of a mouse, the bat immune system can quickly reverse their response by releasing anti-inflammatory cytokines.

Other researchers have suggested that bats’ super-tolerance might have something to do with their ability to generate large repertoires of naïve antibodies, or the fact that when bats fly, their internal temperatures are increased to around 40oC (104oF), which is not ideal for many viruses. Only the viruses that have evolved tolerance mechanisms survive in bats. These hardy viruses can therefore tolerate human fever. What is a good thing for bats is a bad thing for humans.

So, what can we do to prevent future outbreaks of bat viruses? We certainly cannot create vaccines and drugs for all these emerging pathogens. However, there is a need to study the interactions between bats, humans and domestic animals and identify factors that are making bats come into contact with humans and domestic animals, and try to do something about it.

Bats are migrating earlier due to climate change, and this could spell trouble for our crops

Not a lot of people know this, but bats provide excellent pest control that saves farmers billions each year. A new study, however, suggests that climate change is making migratory bats arrive in Texas (from Mexico) earlier than they used to two decades ago. This is a dangerous pattern: the bats risk not finding enough food since the insects and other creatures they prey on haven’t hatched or migrated themselves yet. This poor timing could significantly reduce bat populations, jeopardizing farming operations in the process.

Scientists at Rothamsted Research, an agricultural laboratory in England, initially analyzed radar data from some 160 U.S. weather stations to investigate how accurate radar is for gauging bat colony numbers and movements. When the bats emerge for their night-time foraging, they can cover the sky in massive clouds which show up on radar. However, over the course of their study, the researchers gained a more important insight — that bats were leaving their winter homes in Mexico earlier and reproduced sooner than they had two decades ago. The data that the researchers investigated tracked bat activity in Texas from 1995 through 2017.

According to Phillip Stepanian, Rothamsted meteorologist and co-author of the new study, this behavior coincides with warming temperatures experienced over the last decades.

“This was very surprising,” the researcher told Scientific American. “We weren’t out looking for climate change,” he says, “but then it suddenly became very obvious.”

What’s more, the researchers also found that more and more bats are overwintering at the Bracken Cave near San Antonio, Texas, rather than going back to their cold weather quarters in Mexico. This sort of behavior is unprecedented since the first bat survey in the area began in 1957. According to Stepanian, overwintering is another sign of altering behavior due to warming temperatures. Previously, a study on migratory bats in Indiana found that temperature variations also affected arrival and departure times. Early arrival at their summer nests can expose the bats to cold snaps that might freeze them to death — that’s besides not finding enough food.

“These bats spend every night hard at work for local farmers, consuming over half of their own weight in insects, many of which are harmful agricultural pests, such as the noctuid moths, corn earworm and fall armyworm,” said Charlotte Wainwright, co-author of the new study.

“We found that the bats are migrating to Texas roughly two weeks earlier than they were 22 years ago. They now arrive, on average, in mid March rather than late March,” the scientist added.

In such conditions, the bats might struggle to feed their pups or might even decide to skip reproduction entirely. Overall, this will lead to fewer and fewer bats, to the point that some Midwestern bats may be threatened with extinction.

Such declines could have grave consequences for human activity, particularly agricultural production. By one estimate, bats indirectly contribute around $23 billion to the U.S. economy by controlling pests such as plant-eating insects or by eating bugs that prey on pollinators. In the future, the researchers plan to further investigate the link between climate change and shifting bat migratory patterns. They also hope that weather radar networks around the world can be integrated to provide a continent-wide survey of bat populations.

Scientific reference: Phillip M. Stepanian, Charlotte E. Wainwright. Ongoing changes in migration phenology and winter residency at Bracken Bat CaveGlobal Change Biology, 2018; DOI: 10.1111/gcb.14051

Credit: Max Pexels.

How bats don’t get sick despite carrying the highest number of viruses

Credit: Max Pexels.

Credit: Max Pexels.

Bats are thought to be the number one carrier of diseases, hosting a myriad of pathogenic viruses from Ebola to SARS-CoV. But despite hosting so many deadly viruses, bats show no clinical signs of disease. Scientists have always wondered what allows bats to be virus reservoirs while simultaneously remaining healthy. Now, Chinese researchers may have found the answer. Their study suggests that bats employ an antiviral pathway called STING-interferon, which provides the flying mammals with just enough defense against illness without triggering a hightened immune reaction.

The super flying mammal

Previously, a study published in Nature compiled all the viruses known to infect mammals, which included about 600 viruses found in more than 750 species. It turns out that out of all the species assessed, bats carried the highest number of these viruses. And along with the addition cytosolic DNA generated by these viral infections, bats also get DNA damage due to the metabolic demand of flight. However, they still a have a longer lifespan than terrestrial animals their size. What’s their secret?

Scientists at the Wuhan Institute of Virology in China set out to learn what makes bats ‘super mammals’. They got their first clues in 2013 when the researchers discovered innate immune genes that are positively selected. This set them on the path of investigating bat innate immunology, which eventually led them to the “super bat” interferon. Interferons (IFNs) are proteins released by body cells in response to pathogens such as viruses, bacteria, parasites, as well as tumor cells

Experiments led by Peng Zhou, a professor at the Wuhan Institution of Virology, ultimately revealed that bats have a dampened immune pathway called the STING-interferon pathway. STING is an essential adaptor protein in multiple DNA sensing pathways.

The bats dampen the pathway to prevent an over-response of the immune system. We know, for instance, that an activated STING pathway is linked to severe autoimmune diseases in humans. In bats, there’s a “balance between the bat’s immune system and viruses,” Zhou told ZME Science.

It’s likely that that bats arrived at this defense strategy as a result of three interconnected features of bat biology: bats are flying mammals, have a long lifespan (five different species have been recorded to live over 30 years in the wild), and are host to a huge viral reservoir.

In the end, the bat is not only able to survive in spite of harboring hundreds of viruses, but instead, it actually thrives. Perhaps one day we’ll be able to apply some of the bat’s tricks in medicine, or so Zhou hopes.

“Eventually we can learn from bats to deal with either over response or to control virus replication. We are working on both directions. For example, if there are antiviral genes or inflammation depress genes that are unique to bats (we have primary evidence ) will these apply to us?” Zhou said.

Findings appeared in the journal Cell Host & Microbiome.

Side-by-side comparisson between cave-dwelling (left) and surface-dwelling African dwarf crocodiles. Credit: Olivier Testa.

Cave crocodiles that swim in bat poop are evolving into a new species

Scientists are witnessing how an isolated habitat is turning a population of cave-dwelling African dwarf crocodiles into a new species.

Side-by-side comparisson between cave-dwelling (left) and surface-dwelling African dwarf crocodiles. Credit: Olivier Testa.

Side-by-side comparison between cave-dwelling (left) and surface-dwelling African dwarf crocodiles. Credit: Olivier Testa.

Inside the Abanda caves in Gabon, Africa, an unusual population of African dwarf crocs (Osteolaemus tetraspis) will eventually become an entirely separate species. Because they’re living in an isolated habitat, these cave-dwelling crocs are passing unique sets of genes to their offspring, all descending from one very successful individual.

“As a result of that isolation and the fact that few individuals come in or go out, they’re in the process of [becoming] a new species,” said Matthew Shirley, a researcher studying the crocodiles and co-author of the paper. “Whether that happens soon or not is anyone’s guess.”

The animals were first discovered by Richard Oslisly, an archaeologist who was exploring the cave in 2008. Two years later, Oslisly, along with Shirley and Oliver Testa, a cave scientist, captured the first specimen on which they carried out tests. They drew blood from dozens of crocs and then compared morphological and genetic specs with those living above ground. The data suggest that the cave-dwelling crocs split off from their outdoor relatives thousands of years ago.

Guano crocs

The entrance of the Abanda caves where you're greeted by bats. Looks very welcoming. Credit: Olivier Testa.

The entrance of the Abanda caves where you’re greeted by bats. Looks very welcoming. Credit: Olivier Testa.

From the beginning, the researchers knew something was way off about these crocs. For one, their appearance — orange and yellow skin rather than grey — was strikingly different from surface-dwelling dwarf African crocodiles.

The crocs owe this unusual coloring to somewhat gross circumstances — they swim in bat poop all day. The bat excrement, or guano to be more precise, forms a mud-like liquid on the cave’s floor, where the crocs prefer to linger. The sludge has a sort of tanning effect which turns the croc skin orange and yellow.

The reptiles aren’t particularly fond of the guano mud, but they endure it anyway to gain access to food — some of the tens of thousands of bats. They also don’t mind living in a cave at all, which might seem incongruent if you know a thing or two about crocs. Yes, crocodiles are ectotherms, meaning they require ambient heat to survive, which is why you’ll see videos of them basking in the sun. Inside the Abanda caves, however, temperatures always hover around a stable, comfy 22 degrees Celsius (71 degrees Fahrenheit). What’s more, both cave- and surface-dwelling crocs hunt in the dark, since the African dwarf croc is primarily nocturnal. And to top things off, there are no other predators inside the cave which could either threaten the crocs or compete with them for resources. Not even humans, who are too afraid to wander inside the cramped, dark and generally spooky caves.

The two types of crocs on their backs, for comparison. Credit: Olivier Testa.

The two types of crocs on their backs, for comparison. Credit: Olivier Testa.

Up to now, around 30 cave-dwelling crocs have been identified, most of which probably haven’t seen the light of day since they were juveniles and were able to creep outside through openings in the cave system.

It’s amazing to learn about how scientists are witnessing evolution right before their eyes. We don’t know when the Abanda population will transition into a novel species; it might take a couple of generations, perhaps even in the thousand-year range. But, for now, Oslisly is working with partners to make sure the caves are turned into a sanctuary, just to make sure these bizarre crocodiles are protected and actually get the chance to speciate.

 

Fruit bats.

Young bats learn different dialects from their nest mates

When traveling in a foreign country, it helps to learn a couple of basic words and phrases. Things like ‘I’m lost, can you help me?’ or ‘I need to see a doctor’ could prove highly useful and might even save your life. Bats seem to think so too. According to a recent study, young wild fruit bats learn to respond to the calls of different group sounds they are immersed in, even if this “dialect” isn’t the same as their own. Most often, this is a response to a “move out of my way” signal, which can be important to utter in a crowded cave environment packed with thousands of winged mammals.

Fruit bats.

Credit: Pixabay.

The team of researchers at Tel Aviv University raised 14 bat pups with their mothers in three different chambers, with each mum giving birth and raising her young in one of the colonies. In these lab colonies, researchers played three specific subsets of natural bat vocalizations from loudspeakers. The sounds mimicked real cave roosts comprised of 300 bats and were played in different ranges of pitch.

The young bats were also, of course, exposed to their mothers’ normal ‘dialect’ which they used to communicate among themselves. At the same time, each group developed the ability to react to a dialect that resembled the cave roost they were exposed to.

“The difference between the vocalizations of the mother bat and those of the colony are akin to a London accent and, say, a Scottish accent,” Dr. Yossi Yovel of Tel Aviv University explains. “The pups heard their mothers’ ‘London’ dialect, but also heard the ‘Scottish’ dialect mimicked by many dozens of ‘Scottish’ bats. The pups eventually adopted a dialect that was more similar to the local ‘Scottish’ dialect than to the ‘London’ accent of their mothers.”

Human babies and toddlers have a fantastic ability to pick up new languages, soaking patterns and utterances like a sponge. Scientists call this ability ‘vocal learning’ and until recently it was thought to be exclusively the domain of humans and some songbirds. Other animals have been shown to use a form of vocal learning, but these were instances where the animals would mimic human sounds. The young fruit bats, on the other hand, seem capable of vocal learning among their own species, as reported in the journal PLOS Biology. 

“The ability to learn vocalizations from others is extremely important for speech acquisition in humans, but it’s believed to be rare among animals,” Dr. Yovel says. “Researchers have believed that this is what makes human language unique.”

Studies on songbirds suggest that they can learn to sing from one parent. The new study, however, shows that bats tuned in and learn from an entire colony comprised of hundreds of bats. This finding is striking because it finally moves science away from the songbird-model. It also poses important evolutionary questions like whether or not vocal learning appeared independently in humans or whether it’s actually a far more primitive behavior shared among the mammalian group.

“Will they adopt the local dialect or will they be rejected by the group? Or maybe the local colony will change its dialect to adopt that of our bats,” Dr. Yovel says. “There are many interesting avenues yet to explore.”

It’s not the first time bats have surprised researchers with their complex communication. Earlier this year, the same team found that bats discuss and even argue with each other.

White Nose Bat Syndrome spreads deeper into the U.S. — first case confirmed west of the Rockies

The first case of white nose syndrome, a disease that has wreaked havoc on bat populations in the eastern U.S. has been identified west of the Rockies. The disease’s spread threatens to drastically impact bat populations there, altering ecosystems throughout the country.

Hikers discovered a little brown bat with white nose syndrome on a trail east of Seattle last in mid-March this year, the Department of Fish and Wildlife and the U.S. Geological Survey announced on Tuesday. This marks the first incidence of the deadly fungus west of the Rockies. The ailing bat was taken to an animal shelter, where it died two days later.

Picture of a little brown bat with white nose syndrome, taken in New York state, Oct 2008.
Image credits to U.S. Fish and Wildlife Service Headquarters.

USGS National Wildlife Health Center’s Wildlife Disease Diagnostic Laboratories branch chief David Blehert thinks it’s “surprising and unusual” to find the fungus spread this far west — the closest the syndrome has been identified before was Nebraska, some 1,300 miles from the site.

 “We’ve been dreading this,” said senior scientist at the Center for Biological Diversity Mollie Matteson in an interview for The Huffington Post. “This is a drastic jump.”

“This is the first time, to our knowledge, that there has been a long-range jump of the fungus,” Blehert said.

Caused by the fungus Pseudogymnoascus destructan, white nose syndrome can wipe out entire bat colonies. It gets its name from the white fuzzy fungal growths on the noses, wings and ears of affected bats. The devastating disease spreads throughout bodily tissue, disrupting physiological processes and interrupting essential hibernation periods, causing bats to waste away.

It has already caused the deaths of more than 6 million bats in the eastern U.S, in what some describe as the steepest decline or North American wildlife of the past century.

Seven different species of cave hibernating bats in 28 U.S. states and five Canadian provinces have been affected by white nose syndrome since 2006, when the first case was recorded in upstate New York. Two of these species are native to Washington state.

“I wish I could be optimistic, but given what we have seen on the East Coast, it’s hard to,” said Sharlene E. Santana, assistant professor of biology at the University of Washington.

“We knew it was coming [to the West], but we didn’t know it would be so soon,” Matteson said.

Range of white nose syndrome.
Image credits Washington Department of FIsh and Wildlife.

Blehert’s analysis of the Washington bat revealed that the disease was at an advanced stage, suggesting it had been present in the area for quite some time. Genetic sequencing indicates that the animal is a native to the area.

“We don’t know how the fungus got there,” Blehert said.

The fungus could have been transported bat-to-bat — which would have taken an extraordinarily long time. Or, as Blehert suspects, through human travel and trade, one of the largest spreader of infectious diseases. Humans aren’t affected by the fungus but act as carriers and are believed to (unknowingly) play a central part in transporting the disease across the country. Hikers’ and spelunkers’ clothes and gear can transport the fungus, according to the researchers.

Little brown bat with white-nose syndrome in Greeley Mine, Vermont, March 26, 2009.
Image credits Marvin Moriarty/USFWS, via flirk.

Unfortunately there is no proven method to cure the disease or at least halt its spread.

“We had hope that by the time [white nose syndrome] started to spread to the West, that there were more effective treatments in place,” Matteson said.

Scientists are now looking into the genetic code of the fungus to determine its point of origin and try to set up precautions to halt its spread around the world — the fungus most likely arrived in the U.S. on a human carrier from Asia or Europe where it’s endemic. They’re also looking into creating a vaccine that could give the bats a fighting chance against white nose syndrome.

“For years, we have been saying there needs to be stricter protocol put in place to minimize the chance of a jump like this via human transmission,” Matterson added.

Authorities are now putting abandoned mines and caves under lock-down to protect resident bat colonies. Federal agencies encourage visitors to decontaminate themselves and gear before entering an area with bats, but Matteson argued decontamination should be mandatory.

“We have species that are at risk of going extinct; it’s the least that could be done.”

Bats are an integral part of an ecosystem, and scientists are concerned about the chain reaction their loss might have on plant and animal life, including humans. If the bat population declines, insects would thrive and devastate agricultural areas. Populations of disease-carrying insects would also be left unchecked.

However, there might still be hope. Because bats in the western U.S. tend not to hibernate in large groups, the disease might not spread as widely or quickly from bat to bat. But far less is known in general about how bats hibernate on the West Coast, Matterson said, which means the bats could already be dying.

“As the case in Washington indicates, the disease has already been there for a couple years, and it just got discovered this past month,” she added.

“One of the huge problems with white nose syndrome has been that the [government] response was slow to get off the ground, it was disorganized, a lack of leadership, there wasn’t any decontamination requirement for western public lands, no cave closures.”

“There will be more in the future,” she concluded. “We need to learn our lesson.”

Wildlife officials encourage people who encounter sick or dead bats to report it via an online reporting tool or telephone hotline, 1-800-606-8768.

New SARS-like virus can jump directly to humans from bats

A virus similar to SARS has been identified in Chinese horseshoe bats that may be able to infect humans without prior adaptation. Overcoming this genetic barrier could be the first step for an outbreak, according to a study at the University of North Carolina at Chapel Hill.

The newly identified virus, known as WIV1-CoV, could bind to the same receptors as SARS-CoV.
Image credits CDC/Dr. Fred Murphy

In the wake of the recent Zika and Ebola outbreaks which claimed thousands of lives and cost billions in forgone economic development, a team led by Ralph Baric, Ph.D., professor of epidemiology at UNC’s Gillings School of Global Public Health warns of a new, and just as dangerous, virus.

“The capacity of this group of viruses to jump into humans is greater than we originally thought,” said Vineet Menachery, Ph.D., the study’s first author.

“While other adaptations may be required to produce an epidemic, several viral strains circulating in bat populations have already overcome the barrier of replication in human cells and suggest reemergence as a distinct possibility.”

Baric and Menachery used coronavirus sequences obtained from Chinese horeshoe bats, in which SARS also originated. From them, they reconstructed the virus and tested it to see its potential to infect human and mouse cells. The newly discovered virus, which the team dubbed WIV1-CoV, could bind to the same receptors as SARS-CoV; in essence, allowing it to infect the same types of cells. The virus also replicated quickly and efficiently in cultured human airway tissue cells, suggesting it can jump directly to humans from bats.

“To be clear, this virus may never jump to humans, but if it does, WIV1-CoV has the potential to seed a new outbreak with significant consequences for both public health and the global economy,” said Vineet.

Due to a slightly different genetic make-up, SARS vaccines don’t provide protection against it. The good news however is that the antibodies we’ve developed to fight SARS were really good at killing WIV1-CoV in both human and animal tissue samples — giving us a powerful treatment option in case of an outbreak. The only limiting factor when using antibodies, as Ebola treatment ZMapp showed, is quantity; producing antibodies takes time and resources, and if the number of infected runs out of check there won’t be enough to go around.

When SARS (severe acute respiratory syndrome) was first seen in an outbreak in 2002 it spread to nearly 8,000 people, causing almost 800 deaths. It can spread through airborne contact, and in the early stages its symptoms resemble a dry-cough flu; but it can develop rapidly, causing pneumonia, filling of the lungs with fluid and wreaking havoc on the immune system. Baric and his team believe that WIV1-CoV has the potential to induce similar results with proper adaptation to humans.

“This type of work generates information about novel viruses circulating in animal populations and develops resources to help define the threat these pathogens may pose to human populations,” Baric said.

“It’s important to note that it’s not an approach that’s limited to SARS or SARS-like viruses. It can be applied to other emerging pathogens to helping us prepare for the next emergent virus, whether it be MERS, the Zika virus or something we haven’t even heard of yet.”

According to the Centers for Disease Control and Prevention, SARS’ mortality rate can range from less than one percent in patients below 24 years old to more than 50 percent in patients aged 60 and older.

The full paper, titled “SARS-like WIV1-CoV poised for human emergence” has been published online in the journal PNAS and can be read here.

Little_brown_bat3B_close-up_of_nose_with_fungus_New_York_Oct._2008._5765048289

Asian bats resistant to white-nose syndrome that’s killing millions of North American bats

In  just 7 years, a disease called white-nose syndrome has killed more than 5 million North American bats, almost wiping out entire colonies across 25 states. In Asia however, bats that are exposed to the same disease-carrying fungus are infected in far lesser numbers. The situation is still critical, so scientists are interesting in anything that might keep white-nose syndrome at bay.

Little_brown_bat3B_close-up_of_nose_with_fungus_New_York_Oct._2008._5765048289

A bat infected with the fungus that causes white-nose syndrome. Image: Wikimedia Commons

Not much thought is given to bats, nocturnal creatures that inspire both awe and fear. Like bees, bats are some of the most valuable animals that help humans sustain their economic activities. Without bats, insect pests would spawn out of control causing economic damage and disease in humans.

University of California, Santa Cruz, in collaboration with researchers from around the world, conducted field sampling in  at five sites in China and five sites in the United States. Swabs were taken from hibernating bats to identify and quantify the amount of fungus on each. The researchers were careful to choose sites where the latitude and winter climate are very similar.

White-nose syndrome is a disease affecting hibernating bats. Named for the white fungus that appears on the muzzle and other parts of hibernating bats, WNS is associated with extensive mortality of bats in eastern North America. Bats with WNS act strangely during cold winter months, including flying outside in the day and clustering near the entrances of hibernacula (caves and mines where bats hibernate). Bats have been found sick and dying in unprecedented numbers in and around caves and mines.

Download the white-nose syndrome fact sheet from the U.S. Fish and Wildlife Service.

Pseudogymnoascus destructansthe fungus that causes white-nose syndrome, is endemic to Asia and Europe. It was only in 2006 that the fungus spread throughout Northeastern U.S.

“Uniformly, across all the species we sampled in China, we found much lower levels of infection–both the fraction of bats infected and the amount of fungus on infected bats were lower than in North America,” said first author Joseph Hoyt, a graduate student at UC Santa Cruz.

The bats from China could be more resistant because of four factors:  host resistance, host tolerance, lower transmission due to smaller populations, or lower fungal growth rates due to environmental factors. Results suggest that all things were equal other than host resistance, though the biological mechanisms that help the Asian bats repel this destructive disease have yet to be identified.

There’s also reason to believe that not all North American bat colonies are as vulnerable. Though they had a much higher level of infection that Asian bats, little brown bats had relatively low fungal loads. If the variation is a result of genetic differences, it could lead to the evolution of resistance in that species. Big brown bats, have not suffered as dramatically from the disease as other North American species. In contrast, northern long-eared bats, which showed very low variability in fungal loads, have experienced drastic population declines.

“The northern long-eared bat suffers really high fungal loads, and nearly all individuals are infected–there’s no overlap with the Asian species,” said  Kate Langwig, a former UCSC graduate student now a postdoctoral researcher at Harvard University,. “From previous work, we’ve seen their populations crashing toward extinction, so it could be a poor omen for that species.”

Results were published in the journal Proceedings of the Royal Society B.

Too ugly for science? ‘Ugly’ rodents and bats receive less scientific attention

A study conducted by Australian researchers found that scientific journals discourage the study of ‘ugly’ rodents and bats. This group of animals, while often endangered and critical to local ecosystems, remains grossly understudied.

Not cute enough for science? Black flying fox feeding on a palm tree in Brisbane, Australia. Photo by Andrew Mercer.

The scientists reviewed the published literature for each of Australia’s 331 mammal species and found that they can generally be split into three categories: the good, the bad and the ugly. The good are marsupials and monotremes (mammals which lay eggs), and most studies focus on their physiology and anatomy. The bad are introduced mammals, such as foxes, cats and rabbits, and most studies focus on their environmental impact and population control. Then, there’s the ugly – mostly native rodents and bats with studies focusing on … nothing, because there’s not much literature on them.

“The majority of studies on monotremes and marsupials (the ‘good’) are directed towards their physiology and anatomy, with a smaller ecological focus,” the study writes. “By contrast, introduced eutherians (the ‘bad’) have attracted greater attention in terms of ecological research, with greater emphasis on methods and technique studies for population control. Despite making up 45% of the 331 species studied, native rodents and bats (the ‘ugly’) have attracted disproportionately little study.”

According to researchers, one of the main reasons why this category is so understudies is their cryptic nature – they’re small and difficult to spot and monitor. However, there’s also another factor: with limited funding and resources, most scientists choose to focus on charismatic species, largely ignoring the ‘ugly’ category. Scientific journals are also more likely to reject such studies for being “parochial and of limited interest”.

“Current global and national conservation funding largely overlooks these non-charismatic species, and yet these may arguably be most in need of research effort,” said Professor Trish Fleming, a wildlife biologist at Murdoch University in WA, who co-authored the paper with Dr Bill Bateman from Curtin University.

Fleming asks for more funding for the ignored species and political backing to help conservation agencies protect species. She says citizen science programs could help increase research capacity.

Journal Reference.

bat lands

How bats land upside down – mysterious acrobatic feat revealed

The bat is the only flying mammal and among the heaviest in the world. To top it over, it can land upside down a perplexing acrobatic feat which has left scientists scratching their heads for many years. After carefully and systematically studying bat upside landings in slow motion, a group of researchers thinks it has cracked the puzzle: bats employ a nifty trick where one wing stays flapping while the other is moved close to the body. This asymmetry corrects the moment of inertia and center of mass so the bats always land safely upside down.

Birds have it easy. Their bones are hollow and the wing mass/body mass ratio is very small. Bats on the other hand have the bones as other mammals, albeit smaller and more delicate. These are covered in muscles, joints, tendons and skin, which means bats have the highest wing mass/body mass ratio. This doesn’t seem to bother them too much, given they’re excellent flyers. Yet these characteristics should have made it difficult for the bats to perform their most delicate maneuver: landing upside down.

bat upside down

Image: Seaspray’s It’s a Wonderful Life

When bats come in for a landing, they slow down which should make it harder for them to re-orientate themselves. Researchers at Brown University were fascinated by this and decided to investigate. They trained two bats to land upside down on a mesh attached to the ceiling, while recording to whole process.

“We analyzed the video in a very sort of quantitative manner to create a digital version of the bat that is moving. We know all of its angles, the joint angles and wing postures. What they were doing was moving their wings in very characteristic ways in order to manipulate their center of mass and the moment of inertia,” said Kenneth Breuer, from the university’s School of Engineering.

It seems the bats have turned their cumbersome wings into an advantage. Fractions of a second before landing, the bats pull one wing closer to their body while the other is fully extended. By quickly shifting their weight, the bats are exploiting their large wing mass. Effectively the bats are using inertia, just like a figure skater might hold his arms closer to the body to pick up speed.

To confirm this hypothesis, the Brown University researchers made a computer model which mimicked the bats movements. By switching aerodynamic forces or inertia on and off, they could study how the bats would land. When only the bat’s aerodynamics were factored, it couldn’t land upside down as reported in PLOS Biology

“What this tells us is that in bats, with their heavy wings, it’s the inertial forces that are more important relative to aerodynamics,” said Breuer. “That’s a bit of a counterintuitive conclusion. Normally you’d think that an animal would not want to have such massive wings. But here, it turns out that the mass can be used to some benefit.”

Did the bats evolve these heavy wings to land upside down or is the upside down landing just a convenience? It’s hard to tell at this point, given bats evolved from non-flying mammals.  “If we had a time machine and could return to earth in another hundred million years, we might see even lighter wings in bats,” says study co-leader Sharon Swartz, a professor of biology, for National Geographic.