Enlarge / A vampire bat in flight with spread wings. The creatures build strong social bonds through grooming, sharing blood. (credit: Samuel Betkowski/Getty Images) Vampire bats can starve to death if they don't feed for a mere three days, so strong social ties can be key to survival. For instance, a bat will sometimes share food with a hungry member of the same roost, regurgitating any blood it has consumed into the mouth of the hungry bat—a bit like a bloody French kiss.