Scientists found that vampire bats can form cooperative, friendship-like social relationships by regurgitating their ingested blood meals to feed their non-relatives.
The study published on Thursday in the journal Current Biology has shown that vampire bats that share food and groom each other in captivity are more likely to help their neighbors in need when they’re released back into the wild, even if it’s of no obvious benefit to them.
“What’s quite common in animal cooperation is doing something where we both benefit simultaneously,” said the study’s co-lead author Gerald Carter, assistant professor of evolution, ecology and organismal biology at The Ohio State University.
Scientists suggested bats must have long-term reciprocal relationships, but it’s not yet clear how that works, according to the study.
Carter’s team housed female vampire bats and their captive-born offspring in a closed lab colony for 22 months, creating conditions that prompted social bonding behaviors of food sharing and grooming.
Then, they returned the bats to their natural outdoor home roost — a hollow tree equipped with sensors that recorded their proximity to each other every two seconds, and placed same sensors on a control group of wild bats.
Over eight days, the researchers collected enough data from the sensors to show that relationships between the previously captive bats persisted when they returned to the wild.
Vampire bats are very distantly related to primates, but they have a lot of behaviors similar to group-living primates, suggesting that some bats and primates have independently evolved comparable traits to adapt to similar types of social environments, according to Carter.
“Studying animal relationships can be a source of inspiration and insight for understanding the stability of human friendships,” said Carter.