Vampire bats will throw up their food to help feed other hungry bats

Vampire bats might be a little friendlier than their namesake.

An Ohio State University study published Thursday revealed the bats will form social bonds and help one another when they are in need. But the relationships weren't just due to their captive circumstances, they lasted even after they were released into the wild.

The study, published in Current Biology, involved 23 bats which were held in captivity for nearly two years. To encourage bonding, some bats were not given food. In response, others would regurgitate their "blood meals" to share with those who had none.

When they were released into the wild, the bats were fitted with sensors that monitored their proximity to one another. The sensors were also placed on 27 wild bats who were not involved in the captivity portion of the study. Scientists tracked their activity for eight days.

The test bats remained closer with each other than with the wild bats, and their bonds were stronger than bonds wild bats had with one another. This means those who became "friends" in captivity, stuck together in the wild.

Not all bats maintained their relationships, but in a press release, co-lead author Gerald Carter equated this to the human experience of friendship after graduating high school. You may stay in touch with some people but not others, depending on personality and shared experiences.

But this type of bond is a rarity in the animal world, as the bats pay a price when they regurgitate their food to help others. Scientists think there may be a long-term benefit to these relationships in vampire bats, but aren't clear on how that would work, Carter said.

"It's pretty rare outside of humans to have behaviors where I'm paying an obvious cost to help you and you're not related to me," Carter said.