Vampire bats take their name from one of our most feared mythical monsters, and what you know about them is probably pretty scary. Yes, they survive by drinking blood. However, vampire bats are tiny, and mostly attack livestock. They bite into the skin, then lap up the blood as it bleeds out. Cattle don't miss the tiny amount of blood taken, and hardly even feel the bite. It's also true that vampire bats can spread rabies. But among their own kind, these bats can be superheroes.
According to a recently-published study, 23 vampire bats were captured for a social bonding study that lasted two years. Then they were freed and tracked, along with a couple of dozen vampire bats that had not been in captivity. When they went out hunting at night, bats who had been observed as "friends" during the study managed to meet up with each other again in the wild, where they groomed each other and even shared blood. Now, blood regurgitated from a bat will squick you out, but it's a generous gift to another bat. Scientists suspect they may even trade information on where to find blood during these meetings. Read more about the study at ScienceNews.
For further proof of vampire bats' altruism among their own species, scientists at the Smithsonian Tropical Research Institute in Panama observed one bat that took in an infant when its mother died. A bat named Lilith, one of the 23 captive bats referred to above, became ill. Lilith's close friend BD began sharing more food than usual with Lilith and grooming her baby. When Lilith died, BD took over as mother of Lilith's infant, even nursing it, even though BD did not have an infant at the time. Now, that's a good friend.