Common Vampire Bat

## Description

The Common vampire bat is a small, leaf-nosed bat native to Latin America. It is short-haired, with silver-gray fur on its undersides, demarcated from the darker fur on its back. A well-developed, clawed thumb on each wing is used to climb onto prey and to assist the animal in take-off. The Common vampire bat practices hematophagy, mainly feeding on the blood of livestock. The bat usually approaches its prey at night while they are sleeping. It then uses its razor-sharp teeth to cut open the skin of its hosts and lap up their blood with its long tongue. Because it feeds on livestock and is a carrier of rabies, the Common vampire bat is considered a pest.

## Distribution

Common vampire bats are found in parts of Mexico, Central America, and South America. They prefer warm and humid climates and use tropical and subtropical woodlands and open grasslands for foraging. Bats roost in trees, caves, abandoned buildings, old wells, and mines.

## Behavior

Vampire bats live in colonies and have a number of cooperative behaviors such as social grooming and food sharing. Colony numbers can range from single digits to hundreds in roosting sites. The basic social structure of roosting bats is made of female groups and their offspring, a few adult males, known as "resident males", and a separate group of males, known as "nonresident males". Common vampire bats will also roost with about 45 other bat species and are usually the most dominant at roosting sites. They occupy the darkest and highest places in the roosts; when they leave, other bat species move in to take over these vacated spots. Vampire bats hunt at night, using echolocation and olfaction to track down prey. They feed in a distance of 5 to 8 km (3.1 to 5.0 mi) from their roosts. When a bat selects a target, it lands on it, or jumps up onto it from the ground, usually targeting the rump, flank, or neck of its prey; heat sensors in the nose help it to detect blood vessels near the surface of the skin. It pierces the animal's skin with its teeth, biting away a small flap, and laps up the blood with its tongue, which has lateral grooves adapted to this purpose. Common vampire bats are protective of their host and will fend off other bats while feeding and only mothers and their offspring may feed on the same host.

## Diet

Common vampire bats are carnivores and feed primarily on mammalian blood, particularly that of livestock such as cattle and horses. They feed on wild prey like the tapir but seem to prefer domesticated animals, and favor horses over cattle when given the choice.

## Reproduction

Common vampire bats are highly polygynous, and dominant adult males defend groups of females. They may breed year-round, although the number of births peaks in the rainy season. Females give birth to one offspring per pregnancy, following a gestation period of about 7 months. The young are raised primarily by females. Mothers leave their young to hunt and call their young to feed upon returning. The young accompany their mothers to hunt at 6 months but are not fully weaned until 9 months. Female offspring usually remain in their natal groups into adulthood, unless their mothers die or move. The occasional movements of unrelated females between groups lead to the formation of multiple matrilines within groups. Male offspring tend to live in their natal groups until they are 1 to 2 years old, sometimes being forced out by the resident adult males. Common vampire bats reach reproductive maturity when they are 9-10 months old.

## Population

### Threats

There are no major threats facing Common vampire bats at present.

### Number

According to IUCN, the Common vampire bat is locally common and widespread throughout its range but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.

## Fun Facts

Common vampire bats have good eyesight. They are able to distinguish different optical patterns and may use vision for long-range orientation.

Common viper bats also have well-developed senses of smell and hearing. They emit echolocation signals orally and thus fly with their mouths open for navigation. They can identify a metal strip 1 centimeter (0.39 in) wide at a distance of 50 centimeters (20 in).

Vampire bats participate in an interesting behavior called mutual grooming. It is when two bats groom each other simultaneously to clean one another, and to strengthen social bonds. Bats that groom one another also share food. It was suggested that while grooming, a bat might assess the size of its partner's abdomen to determine if it really needs to eat.

While most other bats have almost completely lost the ability to maneuver on land, vampire bats are an exception. They can run using a unique, bounding gait in which the forelimbs are used instead of the hindlimbs to propel forward, as the wings are much more powerful than the legs. Three pads under the thumb function like a sole.

Viper bats are bale to leap in various directions, heights, and distances. When making a jump, the bat pushes up with its pectoral limbs.

Vampire bats' saliva has unique properties; it contains an anticoagulant that keeps blood from clotting.