These Big, Meat-Eating Bats Also Have a Cuddly Side. Rare Videos Reveal ‘Hugging,’ Playing and Sharing Food
Scientists observed a family of four spectral bats in their roost in a tree in Costa Rica, capturing an inside look at their social behavior
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Spectral bats are large, carnivorous creatures that feast on rodents, birds and even other bats. However, despite their fearsome reputation, these flying mammals (Vampyrum spectrum) also appear to have a soft side.
Researchers recently observed a family of spectral bats repeatedly wrapping their wings around each other, cuddling and sharing food, suggesting they might be more social and cooperative than previously thought. They describe their findings in a new paper published August 20 in the journal PLOS One.
Despite their three-foot wingspans, spectral bats are elusive and difficult to study, which means scientists still have many unanswered questions about their lifestyles. But for the new paper, researchers got a rare and close-up look at a roost.
Fun fact: Spectral bats are large carnivores
Spectral bats are the biggest bats in the Western Hemisphere and the world’s largest carnivorous bats. Despite their scientific name, Vampyrum spectrum, the bats are actually “false” vampire bats—they eat meat but don’t drink blood.
They installed a motion-sensitive, infrared camera inside the hollow trunk of a Manilkara tree in Guanacaste Province, Costa Rica, where they had previously discovered four spectral bats roosting. Researchers suspect the creatures were a family made up of an adult male and an adult female, plus offspring born in different years.
Then, they waited. The camera started recording whenever it detected motion over the course of 60 days spread across three months. Scientists ended up with 502 roughly one-minute clips to analyze, including 73 that showed social encounters or other interesting behavior.
Researchers were surprised to see the bats grooming each other and sleeping with their snouts touching while bundled together in a tight “cuddle ball.” Four of the clips showed the bats seemingly hugging for several seconds after one had returned to the roost, interactions that were often accompanied by low-intensity vocalizations.
“These are big apex predators, they can bite through bones … but then at the same time, they’re really gentle,” says lead author Marisa Tietge, a behavioral ecologist at Berlin’s Natural History Museum, to Science’s Jasmin Galvan, adding that she hopes the new research might help people understand bats as “complex, intelligent animals … rather than just seeing them as these untouchable, scary creatures.”
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Scientists don’t know exactly why the bats engaged in these social behaviors. But they suspect it has something to do with the species’ parental style. Spectral bats tend to be monogamous, with both parents helping to raise their young. The cooperative behaviors might be one of the keys to ensuring the survival of their offspring. “Hugging seems to be their way of keeping family bonds strong,” Tietge tells Science News’ Jay Kakade.
The footage also showed the bats sharing food with one another in 12 clips. When an adult bat returned to the roost with a carcass between its teeth, it often gave its catch to a younger bat. One possible explanation for this behavior is that it helps the young bats transition from their mother’s milk to solid food, according to the study. In addition, the male bat was observed bringing the female dead birds and mice to eat while she was nursing the younger pup.
Surprisingly, “there was no aggression, no conflict” over the shared meals, Tietge tells Science. The bats seemed to intuitively understand which food was meant for them and which was meant for other members of the family. Only once did the cameras record an apparent dispute over food, “resembling a tug-of-war scenario,” according to the paper.
The bats were also seen leaving the roost together, likely in search of prey. This was unexpected, as scientists previously assumed spectral bats hunted alone.
Other clips showed the bats goofing around: Some footage captured the mammals playing with each other or chasing cockroaches around inside the tree trunk.
Although the study’s sample size was small, researchers say the findings are important all the same. Since scientists know very little about spectral bats, “every new observation of bats’ social behavior is valuable,” says Yossi Yovel, a neuroecologist at Tel Aviv University in Israel who was not involved with the research, to Science News.
In addition, this work might also help shed light on the health of the Latin American forest ecosystem more broadly. “If we know a certain species behaves in this way, and then suddenly the behavior changes, then we know something is wrong,” Tietge tells the New York Times’ Kate Golembiewski.
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