Common Vampire Bat

May 22, 2022 News

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Kaieteur News – The common vampire bat (Desmodus rotundus) is a small, leaf-nosed bat native to Latin America. It is one of three extant species of vampire bat, the other two being the hairy-legged and the white-winged vampire bats. 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.
The species is highly polygynous, and dominant adult males defend groups of females. It is one of the most social of bat species with a number of cooperative behaviours such as social grooming and food sharing. Because it feeds on livestock and is a carrier of rabies, the common vampire bat is considered a pest. Its conservation status is categorised as Least Concern by the International Union for Conservation of Nature (IUCN) because of “its wide distribution, presumed large population tolerance of a degree of habitat modification, and because it is unlikely to be declining at nearly the rate required to qualify for listing in a threatened category.
Physical description
The common vampire bat is short-haired, with silver-grey fur on its undersides, demarcated from the darker fur on its back. It has a deeply grooved lower lip, and a flat, leaf-shaped nose. A well-developed, clawed thumb on each wing is used to climb onto prey and to assist the animal in take-off. The bat averages about 9 cm (3.5 in) long with a wingspan of 18 cm (7 in). It commonly weighs about 25–40 grams (2 oz), but its weight can drastically increase after a single feeding. The braincase is relatively large, but the snout is reduced to accommodate large incisors and canines. It has the fewest teeth among bats. The upper incisors lack enamel, which keeps them razor-sharp. Its dental formula is 1.1.2.01.1.3.0, for a total of 18 teeth.
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. This ability likely evolved independently within the bat lineage. Three pads under the thumb function like a sole. It is also capable of leaping in various directions, heights, and distances. When making a jump, the bat pushes up with its pectoral limbs. The hindlimbs keep the body over the pectoral limbs which are stabilised by the thumbs.
Common vampire bats have good eyesight. They are able to distinguish different optical patterns and may use vision for long-range orientation. These bats also have well-developed senses of smell and hearing: the cochlea is highly sensitive to low-frequency acoustics, and the nasal passages are relatively large. They emit echolocation signals orally, and thus fly with their mouths open for navigation. They can identify a metal strip 1 centimetre (0.39 in) wide at a distance of 50 centimetres (20 in), which is moderate compared to other bats.
Range and habitat
The common vampire bat is found in parts of Mexico, Central America, and South America, as well as the Caribbean islands of Margarita and Trinidad. They can be found as far north as 280 kilometres (170 mi) south of the Mexico–United States border. Fossils of this species have been found in Florida and states bordering Mexico. The common vampire is the most common bat species in southeastern Brazil. The southern extent of its range is Uruguay, northern Argentina, and central Chile. In the West Indies, the bat is only found on Trinidad. It prefers warm and humid climates, and uses tropical and subtropical woodlands and open grasslands for foraging. Bats roost in trees, caves, abandoned buildings, old wells, and mines. Vampire bats will roost with about 45 other bat species, and tend to be 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.
Behaviour
Feeding
The common vampire bat feeds primarily on mammalian blood, particularly that of livestock such as cattle and horses. Vampire bats feed on wild prey like the tapir, but seem to prefer domesticated animals, and favour horses over cattle when given the choice. Female animals, particularly those in estrus, are more often targeted than males. This could be because of the hormones.
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. The blood is kept from clotting by an anticoagulant in the saliva.
They are protective of their host and will fend off other bats while feeding. It is uncommon for two or more bats to feed on the same host, with the exception of mothers and their offspring.
Mating and reproduction
Male vampire bats guard roosting sites that attract females, but females often switch roosts. During estrus, a female releases one egg. Mating usually lasts three to four minutes; the male bat mounts the female from the posterior end, grasps her back with his teeth, holds down her folded wings, and inseminates her. Vampire bats are reproductively active year-round, although the number of conceptions and births peak in the rainy season. Females give birth to one offspring per pregnancy, following a gestation period of about seven months. The young are raised primarily by the females. Mothers leave their young to hunt, and call their young to feed upon returning. The young accompany their mothers to hunt at six months, but are not fully weaned until nine 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 leads to the formation of multiple matrilines within groups. Male offspring tend to live in their natal groups until they are one to two years old, sometimes being forced out by the resident adult males.https://en.wikipedia.org/wiki/Common_vampire_bat – cite_note-mating-26 (Source: Wikipedia)

 

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