Upper-class hyenas inherit social contacts to live longer and maintain the “status quo” of the herd

Upper-class hyenas inherit social contacts to live longer and maintain the "status quo" of the herd  Science

Inheritance of social rank is not uncommon in nature, certainly not among people. And it is also common for descendants to inherit their parents’ social relationships, as with African elephants and macaques. Including hyenas that have social structures very similar to these monkeys. The study, published today, analyzed half a million interactions between hyenas over 27 years of scientific observation to conclude: hyena pups maintain social contacts with their mothers, especially those who are high in the group. A phenomenon that has important consequences for the life of these animals.

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Hyenas are one example of matriarchy among mammals: they rule and males migrate to find a new herd. Therefore, in this study which publishes a magazine on its cover titleonly, focus on the relationships that hyenas inherit from their mothers. The result leaves no room for doubt: even years after leaving the lair, high-ranking hyenas maintain strong ties with the same individuals with whom their parents were associated, even after they died. Those who have a low social class tend to be much more different and seek different and stronger friendships than those of their low-ranking mothers to try to compensate for their vulnerable situation. And this has two simple consequences: the stability of the group is maintained for decades (usually living up to 25 years), they are in charge of the same families and the average life expectancy of higher-grade hyenas is increasing.

For Holekamp, ​​hyenas pass on to their young a legacy similar to the human, “less tangible things such as languages, beliefs, and social groups.”

Researcher Kay Holekamp of Michigan State University (USA) believes she is studying in the USA titleonly suggests how something as rich and complex as the cultural heritage we see in humans may begin during the development of other mammals, such as the social heritage learned in spotted hyenas. “Apart from the physical manifestations of wealth or poverty,” says Holekamp, ​​“we know that what people pass on to their children as an inheritance is much less tangible things, such as languages, a whole set of cultural norms, beliefs, and groups of relationships with others. members of our companies “. Hyenas give their litters a similar advantage, Holekamp explains; less sophisticated, but the baselines would be very similar.

Thanks to the friendship of high-ranking hyenas, preferential access to food is ensured, thus avoiding the stress of fighting for rare hyenas left with low status hyenas (groups of up to 130 members) and also allowing more allies in conflicts, which determines the quality and quantity of support.

Three years ago, Specialists from the Leibniz Institute for Zoological and Wildlife Research show in a study how the alliance strengthens the hyena matriarchy. As with bonobos, female hyenas maintain their throne not because they are stronger than males (they are slightly larger than them), but because of the alliances they form in the group to face aggression. As one of the authors of this work explains, Eve Davidian, showed that the number of relatives an individual can rely on, and the asymmetries between individuals strongly predict the relationship of dominance between two hyenas. “However, it was not clear how these asymmetries arose;” this study provides an explanation, ”says Davidian.

“In hyenas, social rank is inherited by learning.” It is not determined by physical strength or other genetically transferable properties. ”

Kay Holekamp, ​​Michigan State University

Allies who have young hyenas strongly determine the outcome of their disputes, Holekamp explains: “Youth high-ranking bloodlines they have more support because they have more relatives and they also attract what we might call groupies, women of lower order who like to hang out with more dominant women “.

“We already knew that in hyena societies, social rank has important effects on adaptability, and that.” is inherited by learning. In other words, it’s not determined by physical strength or other genetically transferable traits, ”explains a Michigan State University expert who has been studying hyenas in Africa for three decades. This study now shows that in addition to social rank, mothers also inherit complete sets of relationships, especially between high-ranking individuals. “This also applies to people,” says the zoologist.

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