Common Vampire Bat

The Common Vampire Bat is one of only three species of vampire bat. They are between 7 and 9 cms (2.75 - 3.75 inches) in length, they have no tail, a wingspan between 35 and 40 cms (13.8 - 15.8 inches) and they weigh between 19 and 45 g (0.7 - 1.6 oz). 

They are brownish/grey in colour with a paler underside. Their ears are pointed and their muzzle is flat and leaf-shaped. They have specialized front teeth, lips and tongue to aid them whilst feeding - their feeding method is described below in the "Diet" section. 

They are one of the few bats that are capable of walking, jumping and hopping and they accomplish this by folding up their wings so that they walk around on their thumbs. This is particularly important for the Common Vampire Bat as it enables them to stealthily move around on the ground and on their prey.

Common Vampire Bats use echolocation and vision to navigate and find their prey. Vocalizations mainly occur between mothers and their offspring. 

Habitat

Common Vampire Bats are found from Mexico to South America at elevations up to 2,400 m (7,872 ft). They generally live in colonies that contain 20 to 100 individuals but some can be much larger. These colonies roost in caves, tree hollows old mine shafts, old wells and abandoned buildings. 

Diet

Common Vampire Bats feed on the blood of other vertebrates. They primarily feed on livestock such as cattle, horses, pigs and dogs due to their abundance, but they will also feed on the blood of wild animals and humans. 

Their front teeth, lips and tongue are highly specialized to aid feeding. They use their teeth to trim away a patch of fur, then they slice away a piece of skin. During this process they release saliva that contains an anticoagulant, known as Draculin, so that the wound they have created bleeds freely. They have grooves in their lower lip and on the underside of their tongue that form a straw like structure which enables them to suck up the blood. Over a 30 minute period they can consume 25 ml (1 fl oz) of blood. 

If they have chosen a tethered farm animal to feed on, quite often they will return night after night to the same animal and remove the scab to feed once again. 

Breeding

Common Vampire Bats breed year round but most births occur during April and May or October and November. After a gestation period of 7 months females gives birth to a single offspring but occasionally twins are born. At birth the offspring are well developed and weigh approximately 8 g (0.28 oz).

During the first month, young are fed exclusively on milk but after that they are fed on regurgitated blood by their mother. When they reach 4 months old they accompany their mother when she goes to feed and they are fully grown and independent at 5 months old.

Common Vampire Bats reach sexual maturity at 9 - 10 months old. 

Predators 

Predators of Common Vampire Bats are humans and birds of prey. 

Interesting Facts

The Common Vampire Bat is a carrier of the rabies disease.