photo courtesy of Jeane Vogel

 

Vampire bats are sanguivorous animals, and the blood they drink is their only source of food. They feed primarily on the blood of livestock including cows, pigs, and sheep. They have been known to feed on the blood of humans sleeping outside or in poorly enclosed houses. Vampire bats use a combination of sound, smell, and echolocation to locate their prey and heat sensors to locate capillary rich areas on their prey. Contrary to popular belief, vampire bats do not suck the blood, but rather make an incision in the flesh and then drink the blood as it flows from the wound. Their saliva contains an anticoagulant that can keep the blood flowing for up to 20 minutes. They drink about two tablespoons of blood a day, which is equivalent to 60 to 100% of their body weight. They only need the red blood cells, which is a small portion of the total blood volume. To accommodate for this, vampire bats have a specialized stomach and kidneys that rapidly remove the erythrocytes from the plasma, so that the plasma can be secreted (Bolzman 1999).

Since vampire bats have no need to chew their food, they have fewer teeth than any other bat (Holzman 1999). The teeth they do have are used to cut into the flesh of their sleeping prey without being detected. Vampire bats have canines that are shaped specially to clip fur. They also have two razor sharp incisors that cut the flesh almost painlesly. On top of their specialized teeth, they have other tools to help them in their unusual feeding habits. There is a heatsensing organ located in their noseleaf, which enables them to locate areas of the skin that are rich in cappilaries. They also have an anticoagulant in their saliva that keeps the blood flowing while they feed, and a grooved tongue to help the blood flow rapidly to the back of their mouth. (Holzman 1999).

Because the vampire bat’s prey is on the ground, which is different from the other insectivorous or frugivorous bats, vampire bats have developed specialized methods of locomotion. Out of about 925 species of bats identified, only the common vampire bat is able to maneuver on the ground as well as in the air. Bats can also move side to side and backwards (Bolzman 1999).

 

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