Scientists have figured out why vampires needed «girlfriends»

© Photo : Uwe SchmidtЛетучие mouse vampire Desmodus rotundus, the mother and daughterScientists have figured out why vampires needed «girlfriends»© Photo : Uwe Schmidt

. Bats-vampires have girlfriends to make it easier to cope with lack of food when their mother or one of my sisters lost for a long time, the scientists write in an article published in the journal Biology Letters.

«Bats are vampires, feeding of extracted blood of others, not related individuals, get blood from them not more than their more stingy counterparts. The question arises, why do they need to liaise with them unrelated girlfriends? We found out that it helps them to survive in those occasions when they lose one of the main «donors» of blood. A large number of friends strengthens their social and food chain,»says Jerry Carter (Gerry Carter) from the Smithsonian Institute of the tropics in Panama.

Most bats feed relatively soft food, requiring no skills to crack, with insects and fruit. This way of life is well within our understanding of what the ancestors of bats had to sacrifice a lot to ease your body and learn to fly.

But there are exceptions to this rule – there are now six families of bats, including one family of mice-vampires who feed on the flesh or blood of vertebrates creatures. Almost all of them live in the tropics of South America and often pass from the blood of wild birds and animals on the blood of livestock and even people due to massive deforestation and other environmental problems.

As Carter says, the common vampire (Desmodus rotundus) are often unable to earn their living even under ideal conditions when they are hunting does not interfere with people, and sometimes bad luck plagued them for a few days.

If mice-vampires, like their fabulous «cousins» were the singles, then they were threatened with death – the blood of birds and mammals is extremely poor source of calories. Desmodus rotundus almost every day living on the edge of life and death because they do not possess any significant reserves of fat.

Helps them a special «collective» way of life in a closely related social groups whose members are descendants of one female and unrelated individuals, has been observed. More successful vampires, according to scientists, are often produced to share blood with other people, helping them to escape from starvation.

Why they support the sisters, mothers and daughters, is quite understandable from the point of view of evolution, but the reasons of the existence of such «mutual aid» among unrelated individuals to each other remained unclear, says Carter.

Observing the behavior of the «collective» of three dozen vampires for four years, he revealed the roots of «irrational» behaviour, periodically catching some specimens and releasing them back into the flock only a day. Before you do that, Carter removed their sisters or mothers of the pack and looked like hungry bats interacted with other felines.

As it turned out, the «girlfriend» on pack play two important roles – not only do they help returning the mouse to find food, but also calm her down when she discovers that her mother or sister had disappeared.

This situation can often occur in the forests of South America, where vampires are often forced to sleep in «foreign» packs after a long and often fruitless search for food, the scientist believes.

In such cases, a large number of friends, ready to sacrifice blood for the sake of familiar individuals, contributes to the survival of individuals and the entire population as a whole. Similarly, as scientists believe, is arranged populations of other social animals, including humans and primates.