Vampire bats aren’t so different from humans in some ways. These long-lived and extremely social bats form close social relationships – bonds that in humans, we’d call friendships. However, vampire bat friendships are characterized by mutual tongue baths and regurgitated blood. Now, research shows how these friendships form. In a study published today, scientists report that vampire bats gradually build trust through social grooming. The results support a model of how cooperative relationships form that could also apply to human friendships.

Read the whole story at National Geographic: How Vampire Bat Friendship is Surprisingly Like Our Own.