The 3 species of vampire bats that suck blood from animals!


Photo credit: Uwe Schmidt

Vampire bats are not a terrifying legend. They exist and do feed on the blood of livestock, particularly cattle and horses, but they can also attack goats, sheep, pigs and poultry. The 3 species of bats known to date are not only vampires but also venomous. While their venom prevents blood from forming a clot, nature has also endowed them with physical characteristics allowing them to attack species much larger than themselves. Portrait of the only bloodsucking mammal in the world.

What are the 3 species of vampire bats?

Vampire bats belong to the family Desmodontidae. The 3 species of hematophagous bats (which feed on blood) are:

The common vampire (Desmodus rotundus)

The common vampire has a fairly short, two-tone coat: the back is brownish and the belly is lighter. Its wings are blackish with a gray or white and brown underside. Its nose is surrounded by dermal growths forming ridges above the nostrils. Its snout is reduced to accommodate long canines and upper incisors, which are not coated with enamel to remain razor sharp. It is the bat species with the fewest teeth (20). The lower lip is deeply indented. The relatively large skull has short, pointed ears. Desmodus rotundus measures approximately 9 cm in length, with a wingspan of 18 cm and a weight of up to 40 g.

The hairy-footed vampire (Diphylla ecaudata)

Diphylla ecaudata owes its vernacular name to its hairy legs. This bat resembles the common vampire but smaller: it measures between 7 and 9 cm and weighs 30 to 40 g. Its coat has shades of reddish brown to sooty brown. The hairy-footed species has a total of 26 teeth, more than other vampire bat species;

The white-winged vampire (Diaemus youngi)

This third species also resembles the common vampire with smaller measurements: its average length is 8 cm and its weight is 35 to 45 g. Its brownish coat contrasts with the white of the edge of the wings and the tip of the patagium. Diaemus youndi has 22 teeth and its lower incisors are slightly curved. A rarer species, the white-winged vampire is less studied and therefore less known.

Where do vampire bats live?

These 3 species of bats live in the large tropical forests of the American continent, in a vast, immense region that goes from Mexico to the southern plains of Argentina, via Chile, Peru, Uruguay and even Brazil. . Vampire bats are also found in Trinidad and Tobago. These nocturnal mammals take refuge in very dark places, such as caves, hollow trees, cellars or abandoned buildings. Vampire bats form colonies numbering from a few dozen to several thousand individuals. They can nest with other bat species.

What blood do vampire bats drink?

The common vampire is known to primarily drink the blood of large livestock mammals, such as cattle or equines. It can also suck the blood of other domestic animals such as goats, sheep or pigs. The bat also feeds on wildlife such as tapirs, and can very occasionally feed on humans (a few cases have been reported). Its preferred biting areas are the shoulders of livestock, the neck, the base of the horns, the base of the ears, the muzzle, the legs, the tail, the vulva and the anus. The species Diaemus youngi prefers bird blood. Indeed, in the 1950s, scientists Goodwin and Greenhall noticed that in captivity, the white-winged vampire refused the blood of livestock but accepted that of chickens. The hairy-footed vampire also seems to favor the blood of birds.

How does the bat vampirize its victims?

Vampire bats forage at night using echolocation and olfaction to locate prey. The bat lands on a sleeping mammal or bird, then runs over its body looking for a place where the hair (or feathers) are sparse. It moves quickly like a large spider and pierces the skin of its victim with its incisors, lifting a small strip of skin, and laps up the blood with its tongue. The wound is painless and the prey does not wake up. If enough blood does not drain, the bat may bite again or stick its tongue deeper into the wound. According to observations, feeding lasts between 9 and 40 minutes, time for the bat to collect around twenty milliliters of blood.

What are its adaptations to the bloodsucking diet?

Over the course of evolution, these 3 species of bats have developed capacities that are particularly adapted to their blood-sucking diet. Here are some examples:

Vampire bats are capable of galloping on the ground and on the bodies of its hosts. This ability, necessary for hunting live prey, is not essential in frugivorous species which do not move as quickly. Recent studies have shown that vampires can reach speeds of 1.2 m per second; Blood-sucking species use all of their senses to hunt: vision, smell, hearing and echolocation. Additionally, their noses have infrared sensors that detect the heat of warm-blooded animals. Once the bat is on its prey, the heat-sensitive pits in its nose help it detect blood vessels passing near the surface of the skin; The central incisors of the upper jaw of these bats are long, triangular, and razor-sharp in order to pierce the tough skin of cows. The canines, positioned far back, are also large while the lower incisors are spread apart to allow the tongue to pass through. We note that frugivorous species have tiny upper incisors but their molars are more developed; Their long tongue can dig deep into the wound and as soon as blood begins to flow, its edges fold back to form a concave surface that acts like a tube through which blood is drawn. Lapping is also facilitated by the lateral grooves of the tongue; The vampire bat can swallow a huge amount of blood, up to 56g in a single meal (more than its body weight). This large quantity could prevent him from taking off again if his urinary system does not compensate by releasing a quantity of urine with a high proportion of water; Vampire bat: what is its venom used for?

Unlike snake venom which can cause the death of an animal, bat venom attacks its prey in different ways but without trying to kill it. Explanations: vertebrates are equipped with molecules and cells intended to close wounds. At the slightest tear in a blood vessel, they begin to make clots to stem the flow. The saliva of vampire bats contains a substance, draculin, which has anticoagulant power. More specifically, an enzyme dissolves the clots and prevents the blood from clotting, allowing the bat to feed for as long as it wants. The phenomenon explains why wounds continue to bleed for several hours after the vampire leaves. Scientists have also discovered dozens of new proteins, some of which kill microbes, keeping food clean, while others dilate blood vessels, increasing blood flow into the bite.

Are vampire bats dangerous to humans?

Natural predators of the vampire bat include nocturnal birds of prey (barn owl, burrowing owl), snakes (boa constrictor, rainbow boa) or domestic cats. Due to their blood-sucking diet, bats are vectors of parasites (T. hippicum or T. equinum trypanosomiasis) and rabies. Each year, the animal causes the death of thousands of animals in its range. For the record, a serious epizootic occurred in Trinidad and Tobago between 1925 and 1935, causing the death of 89 people in addition to numerous livestock. In 2015 in Peru, the rabies virus transmitted by vampire bat bites caused the death of 12 children in a few months. Today, the bat is still the cause of transmission of the rabies virus in South and Central America as well as in Trinidad. A fierce and nocturnal animal, the vampire bat only comes into contact with humans due to the decline of its habitat and the absence of its usual prey. For comparison, mosquito-borne diseases kill more than 800,000 people each year.

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