Homosexual relations have already been observed in well-known species such as dolphin or penguin, but now scientists have identified many other cases. According to a new study, homosexuality exists throughout the animal kingdom and is indispensable for the survival of some species.

The discovery overturns the beliefs of those who believe that homosexuality is not natural, and scientific knowledge of the lifestyle of the animals. Biologist Nathan Bailey said: “It is clear that sexual behavior between individuals of the same sex go far beyond the few known examples that dominate the scientific literature, for example, among bonobos, dolphins, penguins and flies.”

Nearly a third of the albatross of Laysan were raised by two females. The couples “lesbians” were formed with an aim of raising brooded since the number of males has greatly declined. According to the study, those couples are raising fewer young than heterosexual couples, but their efforts have helped restore declining populations of albatross on the island. Another example: half of the time, male dolphins have sex with other males, while among the bearded vulture, these relationships represent a quarter of the couplings.

Researchers explain that the reason for the formation of gay couples varies depending on the species. “For example, male flies are attracted to other males because they lack a gene enabling them to differentiate the sexes,” says Dr. Bailey of the University of California. “But this is very different about the dolphins, who engage in same-sex relations to facilitate the social ties in the group, or the females albatross which can remain as couple all their life to help to raise the small ones”.

Dr. Bailey and her colleague Marlene Zuk say that homosexuality can also affect the chances of survival of some species, making it “unavailable” for groups of animals capable of reproduction.