Habits: Vampire bats are active only during the darkest periods of the night. It is the time when they are most likely to avoid being caught by such nocturnal predators as owls. Also, the domestic animals on which the bats feed are often sleeping, and so are easier to approach undetected. During the day, vampire bats roost in colonies, hanging upside down in caves and hollow trees. They will sometimes move from one daytime roost to another which is closer to their prey. This kind of activity indicates that vampire bats learn from experience where their prey can be found.

Vampire bats also use rivers as navigational tools as they move from one part of their range to another. The rivers are easier to follow than wooded routes, and cattle often graze in pastures near water. Barely larger than a sparrow, the vampire bat is a fearsome sight. Its wedge-shaped incisor teeth are used for slashing open the skin of its prey.

Food and Feeding: The vampire bat feeds on the blood of animals. Cows, pigs, and horses are its favorite hosts. The bat will usually choose to feed on the most docile or isolated animal in the resting herd. Using its chisel like incisor teeth, the bat makes a small cut in the animals skin. It usually chooses a fleshy area, like the shoulder or neck, where the blood vessels are closer to the skins surface.

The bat then drinks the blood that flows from the wound. Chemicals in the bats saliva keep the blood flowing for the 2-3 minutes that the bat feeds. Often two or three bats will feed from the same wound. In most instances, the host animal suffers no ill effects from the loss of blood, although if too many bats feed on the same animal, it may be severely weakened. When larger prey is not available, vampire bats will attack turkeys and chickens. Vampire bats feed exclusively on livestock, biting their victims in places such as the ear, where the blood vessels run close to the surface.

Breeding: The vampire bat’s ability to reproduce is limited by its need to remain light enough to fly. It gives birth to a single offspring after an unusually long gestation period of six to eight months. Born blind, the young bat is carried by its mother for the first few days of its life. Its eyes open after a week, and it takes its first flight when it is three weeks old. The young bat is sexually mature at nine months and breeds at any time of the year. Vampire bats mate year-round. Mating takes place while roosting upside down in the security of a cave. A single young is then born some 6-8 months later.

Vampire Bat and Man: The vampire bat can transmit rabies to livestock and man. To control the vampire bats, cattle have been injected with anticoagulants, substances that do not harm the cows but will cause internal bleeding in the feeding bats. Anticoagulants have also been smeared on the bats themselves. When they return to their roost site, other bats in the colony groom them and ingest the fatal drug.

Key Facts:
Sizes:
Length: Body, 2 ¼ in.
Wingspan: 8 in.
Weight: 1 oz.

Breeding:
Sexual Maturity: 9 months
Mating Season: All year
Gestation: 6-8 months
No. of Young: 1

Lifestyle:
Habit: Nocturnal. Lives in colonies of 6-2000, but which usually number 100
Diet: Blood of domestic animals particularly cows, pigs, horses
Lifespan: 9 years in the wild; nearly 20 years in captivity

Related Species: There are two species of true vampire bat, Diaemus youngi and Diphylla ecaudata.

Distribution: Central and South America, in tropical and subtropical regions from Mexico to northern Chile and Argentina.

Conservation: Considered a serious pest in areas where cattle and horses are kept because they transmit rabies and other diseases. Vampire bats are not currently endangered.

Feeding Habits of the Vampire Bat: Vampire bats prey mainly on domestic animals, biting them on the neck, shoulder, rump, or ankle. The only thing the vampire bat eats is blood, which it laps from the wound that it makes in its host with its sharp teeth. The bat’s tongue has two lateral grooves which alternately open and close while the bat is feeding. This action draws the blood up the deeply grooved lower lip, channeling it into the mouth. Chemicals in the bat’s saliva prevent the blood from clotting and keep it flowing. An adult vampire bat will consume about five teaspoons of blood per day.

Did You Know:
Vampire bats once preyed on wild animals, but now feed mainly on domestic animals.
Vampire bats have been known to feed on sleeping humans.
In a year, a colony of 100 vampire bats consumes a quantity of blood equivalent to the amount in 25 cows.
Vampire bats bite more calves than cows, probably because the youngsters sleep for much longer periods.

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