Common vampire bat

Vampire bats drink a little blood for their dinner.

They mostly visit big animals like cows, horses and pigs at night. The bat makes a tiny cut and licks up a small drink.

Common vampire bats feed only on blood. In the wild they mostly feed on livestock, such as cows, horses and pigs, because there are so many of them, and they also visit large wild mammals such as tapirs.

A vampire bat does not suck blood. It makes a small cut with its sharp front teeth and laps up the blood with its tongue. Special proteins in its saliva stop the blood from clotting. The bite is fairly painless and rarely wakes a sleeping animal.

Desmodus rotundus is an obligate blood feeder. ADW reports that in the wild it feeds preferentially on livestock because they are abundant, but also on wild animals and people; Bat Conservation International lists large wild mammals such as tapirs and livestock including cattle, horses and pigs.

The bat makes an incision about 3 millimeters long with its incisors and laps the blood rather than sucking it, while anticoagulant proteins in its saliva keep the wound open. The bite is relatively painless and rarely wakes a sleeping animal. An anticoagulant discovered in vampire bat saliva has been developed into a medication that helps prevent strokes (Bat Conservation International).

Vampire bats live together in big groups.

They clean each other's fur. Friends share some of their food. Mothers and babies call to each other.

Common vampire bats are very social. Female bats form close friendships with other females that last for many years. They groom each other's fur, and a bat will often bring up part of its blood meal to share with a roost mate that has just groomed it.

Who shares with whom depends on whether the bats are relatives, how often they roost together and whether they have helped each other before. Mothers and their young keep in touch with small calls.

Colonies contain both sexes, but the closest bonds form among females and between females and their young; adult males do not form close ties in the roost, and associations between females last many years (IUCN, ADW). Social grooming, though less frequent than self-grooming, is closely linked to food sharing: a female grooms another for up to two minutes, and the groomed bat then regurgitates part of its blood meal for the groomer (Wilkinson 1986, cited by the IUCN).

Bat Conservation International notes that sharing depends on kinship, association and reciprocal help. Young bats play with other juveniles and use an appeasement posture with older bats. Vocal contact is commonest between mothers and offspring, with pup contact calls at 6 to 12 kilohertz.

There are lots of common vampire bats.

They are not in danger. Scientists have even made a medicine from something in their spit.

The IUCN lists the common vampire bat as Least Concern. It is common and widespread, and it can live in places changed by people.

Vampire bats can spread a disease called rabies to livestock and people, and they cause big losses for cattle farmers in Latin America. Because they spread rabies, people sometimes destroy whole colonies. The IUCN says teaching people about these bats can help prevent this.

The IUCN assessed Desmodus rotundus as Least Concern in 2015, with a stable, abundant population that tolerates some habitat modification. It is persecuted because it transmits rabies, though this is not considered a major threat, and the IUCN recommends education to prevent further elimination of colonies.

ADW reports that the bat transmits rabies to people and livestock, and that losses to the cattle industry in Latin America amount to many millions of dollars a year. On the positive side, an anticoagulant from its saliva has been developed into a stroke-prevention medication (Bat Conservation International), and guano from roosts can be used as fertilizer (ADW).