Animal behavior: for spotted hyenas, the social status of the mother determines the length and quality of life | United States



Inheriting social status is not unusual in nature, certainly not in humans. It is also common for descendants to inherit social relationships from their parents. This has been observed in African elephants and macaques, and now also in spotted hyenas, whose social structures are very similar to those of macaques.

A new study published in the journal Science analyzed 73,767 social interactions among wild spotted hyenas collected over 27 years and came to the following conclusion: juvenile hyenas had similar social associations to their mothers, and the strength of the association was higher for status mothers superior. This phenomenon has important implications for the survival of hyenas.

Spotted hyenas are an example of a matriarchal system in mammals: females are in charge and males go in search of new packs. According to the study, even years after leaving the den, higher status hyenas retain strong relationships with the same individuals as their associated mothers, even after their mothers die.

Lower status hyenas, on the other hand, tend to seek out many different relationships in an effort to compensate for their greater vulnerability. This has two obvious consequences: the group remains stable for decades (spotted hyenas can live up to 25 years) with the same families in charge, and higher status hyenas can hope to live longer.

Kay E. Holekamp, ​​a Michigan State University researcher and co-author of the study, believes their work illustrates how something as complex as cultural heritage, which we observe in humans, can be seen through the inheritance of social status in spotted hyenas. . “Besides the physical manifestations of wealth or poverty, we know that humans convey much less tangible things such as language, complete sets of cultural norms, beliefs, and groups of relationships with other members of our. companies, ”she said.

The group remains stable for decades (spotted hyenas can live up to 25 years) with the same families in charge, and higher status hyenas can be expected to live longer

Spotted hyenas provide their young with similar benefits, although these are less sophisticated than in humans. Being friends with higher status hyenas means priority access to food and avoiding the stress of fighting for leftovers in 130 member packs. It also means having more allies in times of conflict.

Three years ago, specialists from the Leibniz Institute for Zoo and Wildlife Research showed in a study how alliances strengthen the matriarchy of hyenas. Much like the female bonobos, the female spotted hyenas keep the throne not because they are stronger than the males (although they are slightly taller than them), but because of the alliances they make to make in the face of attacks.

One of the authors of this study, Eve Davidian, says their work has proven that the number of parents an individual can rely on and the asymmetries between individuals are powerful predictors of the dominance relationship between two hyenas. “But it was not clear how these asymmetries emerged; this study provides explanations, ”she adds.

For young hyenas, having allies can significantly determine the outcome of a dispute, says Holekamp. “Young individuals from a higher status line have more support because they have more parents and because they also attract what we might call groupies, lower status women who enjoy spending time with them. dominant women. “

“We already knew that in hyena societies, social status has important effects on adaptability and that it is inherited through learning. That is, it is not determined by physical strength or other traits that can be transmitted genetically, ”says Holekamp, ​​who has been studying hyenas in Africa for three decades.

The study shows that in addition to social status, entire sets of relationships are passed down from mother to offspring, especially among high-ranking individuals. “This is also true for humans,” notes the zoologist.

english version by Susana Urra.


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