For your next casual conversation. A "Sheldon" factoid that will amaze your friends:
The vampire bat emerges from its cave at the darkest hour of night, after the moon has set. It flies low across the landscape, hunting by smell and sonar. Once the bat finds a victim—and it can feed on most warm-blooded animals, from songbirds to cattle—it starts stalking its prey. The bat lands silently a few feet away, then runs on its wings toward the sound of a pulsing vein. A pair of teeth sharper than a scalpel cut into the flesh. Blood leaks from the wound; the bat laps it up. Sometimes, the bat consumes its weight in blood during the night.I almost starved to death in 60 hours once. Actually, it can happen between breakfast and lunch.
Although the vampire bat has traditionally been seen as a ghoulish predator, it interests biologists for a very different reason: it is deeply altruistic. The bats live in expansive colonies, with hundreds or thousands sharing the same dark cave. Bats must feed constantly—they starve to death within sixty hours—and this has led to the evolution of an unusual way of sharing food. If a vampire bat fails to find a victim during the night, it will begin licking the wings and lips of a chosen colony member. The animals then lock mouths, while the successful hunter starts vomiting warm blood. If such sharing did not take place, scientists estimate that more than eighty per cent of adult vampire bats would die of starvation every year. [More]