Animals

Bloodthirsty vampire bats prefer drinking with friends

Cooperating with familiar bats while hunting may save time and energy

Common vampire bats form social bonds at the roost by sharing food and grooming each other. New research suggests that these bonds hold when bats go out hunting.

S. Ripperger (CC BY 4.0)

By Jonathan Lambert

October 29, 2021 at 6:30 am

Vampire bats may be bloodthirsty, but that doesn’t mean they can’t share a drink with friends.

While on the hunt, vampire bats sometimes fight over the blood of bitten animals. But new research suggests that bats who like each other often team up while hunting. Researchers shared those findings September 23 in PLOS Biology.

Scientists knew that vampire bats (Desmodus rotundus) can form long-term social bonds with certain roost-mates. (A bat’s roost is where it lives, like a cave or hollow tree.) In the roost, bats can bond through grooming and hanging out. They can even share regurgitated blood meals. But until now, no one knew whether those bats still acted like pals while out hunting.

“They’re flying around out there, but we didn’t know if they were still interacting,” says Gerald Carter. He’s an evolutionary biologist. He works at the Ohio State University in Columbus.

Carter studied the social lives of vampire bats with Simon Ripperger. He works at the Museum of Natural History in Berlin, Germany. The team built on past research. By outfitting the animals with “backpacks,” they uncovered a bat colony’s social network. Carter and Ripperger glued tiny sensors to 50 female bats in Tolé, Panama. Those backpacks were sensors that allowed the scientists to track how close each bat was to the others. This revealed which bats met up while hunting.

Two common vampire bats feed on a cow near La Chorrera, Panama. It can take 10 to 40 minutes for a bat to bite a small, diamond-shaped wound into an animal’s flesh, and fights can sometimes break out over access to wounds. But bats who are friendly back at the roost likely feed together in the field, researchers now find. This cooperation could save the bats time and energy.

Bat buds rarely left home together. It seems the bats don’t go on tightly coordinated hunts, Carter concludes. But bonded bats were more likely than strangers to meet up in the field and feed together. Meetings between friends also lasted longer, on average, than other encounters. That was especially true for bats with many roost buddies.

“These are more or less haphazard encounters,” Carter says. He suspects that the bats mostly forage alone. But when bats meet a friend drinking blood from a cow, for instance, they’ll feed together instead of fighting or flying off to find other food. Biting a new wound can take 10 to 40 minutes, Carter says. Sharing with a friend could save these bloodthirsty bats time and energy.