Recognizing relatives is extremely important in nature. It helps to create relationships, share food, and create a safer habitat. However, it is obvious that only close relatives are easy to recognize, but scientists wanted to know whether animals can recognize distantly related, unfamiliar individuals of the same species.
It turns out that some can. One of them is Siberian jay, as scientists from the University of Zurich recently demonstrated for the first time. Scientists say that such ability gives a great advantage when forming cooperation ties.
Siberian jays belong to the crow family and are able to accurately assess the degree of kinship to unfamiliar individuals, which is very rare ability. Only a few species of mammal, birds and fish possess such ability to recognize unfamiliar siblings, but until now scientists did not know if there are species that can recognize distant unfamiliar relatives too, not just siblings. And now recently conducted study showed that Siberian jays evolved such ability, which gives them a significant advantage as cooperation in the wild is extremely important. Usually kinship is the way individuals choose their cooperation partners.
Scientists say that reasons behind favouring related individuals for cooperation is rather simple and selfish – helping related individuals actually helps to propagate your own genes. This is why most insects, meerkats or birds that breed cooperatively, i.e., individuals help to raise offspring that are not their own, live in family groups. Such groups are common for Siberian jays as well.
This species of birds live in Northern Scandinavia and the Siberian taiga. Individuals group into family groups that share a territory. In these groups there are non-breeding birds – those who are very young offspring that remain with their parents for several years beyond independency and those who immigrate into the group at young age.
Breeding pairs are usually very kind to their own offspring that live in the group. However, they are not so nice to unrelated young individuals and even chase them away from food. Research team from the University of Zurich used genetic relatedness analyses to discover that breeding couples are especially aggressive towards the most distantly related group members. It means that Siberian jays are able to recognize even distantly related individuals.
Michael Griesser, first author of the study, explained: “This finding reveals that Siberian jays are able to recognize fine-scale differences in their kinship to other individuals, even to individuals that are unfamiliar to the breeders before they settle in their group”. However, even though scientists know that other bird species identify relatives based on their appearance or calls, it is still unknown how Siberian jays assess the degree of kinship of unfamiliar individuals.
Siberian jays do not breed cooperatively, but do cooperate in other matters. Breeding couples protect their young against predators and share food with them. They do so even after their children are fully fledged and ready for independent life. Scientists performed some experiments, swapping nestlings, which revealed that Siberian jays do not use their ability to recognize kinship of other individuals for their own offspring and are equally tolerant to own nestlings as well as experimentally swapped ones.
Questions stands, why did Siberian jays evolve such ability. Scientists say that answer to this question is in the group behaviour of these birds. They gather at carcasses of large herbivores, such as moose or reindeer, and, in this context, tolerating unfamiliar relatives is an evolutionary advantage, because of preservation of own genes. Furthermore, birds are trying to avoid inbreeding, in which case knowing one’s relatives is very important. Scientists say that kin recognition may actually be widespread between birds but is overlooked in science community.