Vampire bats are leaf nosed bats that range in size from 2.7-3.5 inches long and weigh on average 40 grams. They take their name from the mythological figure due to its many similarities. They can be found in Mexico, Central and South America. Vampire bats typically dwell in caves, but can also be found in mines, abandoned buildings, and other dark places. They sleep through the day hanging upside down in total darkness and come out at night to hunt.
There are 3 types of vampire bats. The common (Desmodus rotundus), the hairy legged bat, (Diphylla ecaudata) and the white-winged vampire bat (Diaemus young). Each of them are very similar to other bats with one exception, vampire bats feed on blood. In fact, vampire bats are the only mammal that has a diet that consists solely of blood.
While the hairy legged and white-winged vampire bats prey mostly on birds, the common vampire bats feed primarily on livestock with a human here and there. When it's time to hunt (near dusk) the vampire bat will fly around and listen for the sound pattern of a sleeping animal. Once they detect a potential victim they land near them and approach it on foot. They use infrared radiation to detect where the blood is closest to the skin on their victim. They then use their razor-sharp teeth to trim any hair and make a surgical cut into the skin to get access to the blood with their tongue. While they are lapping up the blood they use their saliva which acts like an anticoagulant to stimulate blood flow. This feeding session will last somewhere about 20 minutes. When they are done feeding they are too heavy to fly, so they have to find a safe place to continue their digesting. Once they are lighter, they fly back to their roost.
Vampire bats are warm-blooded and need regular sustenance to keep them alive. In fact they cannot live beyond 48 hours without a feeding. So since hunting does not always guarantee you food, the vampire bats have learned to become altruistic and help each other out. For example, when a vampire bat is starving other bats will share their food by regurgitating it for them to eat too. There is of course and expectation that the receiver will become the donor at a later time. I find this fascinating. We can definitely learn from vampire bats in this regard.
I hope you enjoyed the read and learned a bit more on vampire bats. Thanks!