Vampire bats (Desmodus rotundus), whose diet consists entirely of the blood of other animals, often struggle to drink enough blood each night and can miss meals, reports Science News. If they don’t get enough blood for three straight days, they can die, but social bonds between the bats help them get enough food. Some bats regurgitate part of their blood meal to feed others. Researchers have found that these bonds can persist in bats that are captured and later released into the wild, according to a study published yesterday (October 31) in Current Biology.
Gerald Carter, an evolutionary biologist at Ohio State University and a research associate at the Smithsonian Tropical Research Institute, and his team caught 17 wild bats from the same colony and kept them in captivity for nearly two years. During this time, the researchers observed that some bats formed social bonds by regurgitating part of their blood meal to feed others that had been withheld food. Interestingly, the animals shared food with unrelated adults in the group in addition to feeding their own offspring.
“We could see that during the time the bats are in captivity that some of their relationships are getting stronger,” Carter tells NPR. “Almost certainly, there were some bats that were forming new relationships in captivity.”
The scientists then attached tracking sensors to the animals and released them back into the wild. Captive bats tended to spend more of their time together and roost near each other than with a control group of wild bats in the same colony. “The bats who had stronger bonds in captivity had stronger bonds in the wild,” Carter tells Science News.
Surprisingly, the six offspring that were born to the bats during captivity did not fare so well in the wild, according to Science. Many of them roosted outside of the area where the rest of the colony lived, and they showed signs of aggression toward the other bats. By the end of the study, the young bats had flown away—perhaps in an attempt to get back to the area where they were born.
Emily Makowski is an intern at The Scientist. Email her at firstname.lastname@example.org.