Because vampire bats like to suck blood

We won’t turn around, vampires exist. No, we’re not talking about grim, emaciated and devilish humanoid individuals, but small South American bats hematophagous, i.e. blood consumers.

In a new scientific article published in Science Advances, some scientists have tried to understand the genetic basis of this “macabre” diet. The vampire bats are in fact unique among mammals to rely exclusively on this nutritional source, unlike the many “bloodsucking” invertebrates such as mosquitoes, bedbugs and leeches (with very low metabolic needs).

Common vampire bats
in the picture: Common vampire bats

Most mammals could not survive on a low calorie liquid diet like the hematophagous diet, and unlike what is believed, in fact, all 1400 species of bats eat mainly insects, fruit, nectar, pollen or meat, such as small frogs. and fish. They are an exception only three species the vampire batsa group of bats from the Desmodontinae subfamily living in South and Central America.

Vampire bats are basically living Counts Dracula, “as one of the study’s authors jokingly stated, Michael Hiller of the Max Planck Institute. About 8 centimeters long with a wingspan of 18 centimeters, these bats bite and then lick the blood from livestock or other animals at night. The problems with this type of power supply are manifold: blood is a food rich in iron and proteins but lacking in fats and carbohydrates, the true energy source of any self-respecting meal. To allow their survival over the centuries, generation after generation, natural selection has evolved these small mammals making them real specialists in the sector.

In fact, this exceptional food specialization required adaptations in all aspects of their biology, including morphology, physiology and behavior. To detect prey, the common vampire bat (Desmodus rotundus) shows a well developed olfactory systemadvanced low-frequency hearing and, unique among mammals, the ability to perceive the infrared radiation emanating from the victims’ skin. Compared to other species, it possesses exceptional locomotion abilities to sneak up on its prey and is equipped with upper incisors sharp as razors without enamel and salivary anticoagulants, to cut the skin and avoid scarring.

But what are the genetic adaptations who allowed such a diet? To understand this, the experts compared the genome of common vampire bats with 26 other bat species and identified 13 genes that are missing or no longer working in vampire bats. All of these mutations evolved a single time in the common ancestor of the three species.

Vampire bats are extremely gregarious animals
in the picture: Vampire bats are extremely gregarious animals

Plus these little animals they are absolutely not monstersespecially with their fellow men. In fact, another interesting adaptation concerns thehigh degree of altruism achieved in their complex social groups. With such a low-calorie diet, vampire bats can’t last long without a meal – well-fed ones will regurgitate their food to share with a hungry neighbor. In this task, however, it is essential to keep track of who has helped them in the past, in order to reciprocate the favors received and punish the selfish.

Because vampire bats like to suck blood