The researchers gave wild vampire bats a substance that activated their immune system and made them feel sick for several hours, and then returned the bats to their roost. A control group of bats received a placebo.
Data on the behavior of these bats was transmitted to scientists by custom-made “backpack” computers that were glued to the animals’ backs, recording the vampire bats’ social encounters.
Compared to control bats in their hollow-tree home, sick bats interacted with fewer bats, spent less time near others and were overall less interactive with individuals that were well-connected with others in the roost.
Healthy bats were also less likely to associate with a sick bat, the data showed.
“Social distancing during the COVID-19 pandemic, when we feel fine, doesn’t feel particularly normal. But when we’re sick, it’s common to withdraw a bit and stay in bed longer because we’re exhausted. And that means we’re likely to have fewer social encounters,” said Simon Ripperger, co-lead author of the study and a postdoctoral researcher in evolution, ecology and organismal biology at The Ohio State University.
“That’s the same thing we were observing in this study: In the wild, vampire bats – which are highly social animals – keep their distance when they’re sick or living with sick groupmates. And it can be expected that they reduce the spread of disease as a result.”
The study was published today (Oct. 27, 2020) in the journal Behavioral Ecology.
Ripperger works in the lab of co-lead author Gerald Carter, assistant professor of evolution, ecology and organismal biology at Ohio State. The two scientists and their co-author on this paper, University of Texas at Austin graduate student Sebastian Stockmaier, are also affiliated with the Smithsonian Tropical Research Institute in Panama.
Carter and Ripperger have partnered on numerous studies of social behavior in vampire bats. Among their previous findings: Vampire bats make friends through a gradual buildup of trust, and vampire bat moms maintained social connections to their offspring even when both felt sick.
For this work, the researchers captured 31 female common vampire bats living inside a hollow tree in Lamanai, Belize. They injected 16 bats with the molecule that induced the immune challenge – but did not cause disease – and 15 with saline, a placebo.[…]