Hyenas transmit their social rank



Forget about meritocracy, it all depends on the lair we land in. Spotted hyenas (Crocuta crocuta) live in packs of different sizes, from a few individuals to hundreds, depending on available food sources. They form a matriarchal society in which high hyenas have privileged access to prey, and this is not the only advantage of good social housing in a pack, according to a study published July 16, 2021 in the journal Science. Young hyenas of “highly placed” parents will seek to replicate the mother’s social behavior in their future social interactions and stay more with individuals of the same rank.

This type of transmission is found in other species such as rhesus macaques (Macaque mullet), or African elephant (Loxodonta africana) and is well documented in observational studies. But in this study, the researchers relied on 73,767 interactions between hyenas over nearly 27 years, to identify social patterns thanks to a theoretical model developed in a previous study. “We knew that the social structure of hyenas is based in part on the rank of each in the agonist hierarchy (a set of behaviors associated with conflicts of rivalry between individuals, editor’s note), which we know was inherited from the mother“Erol Akcay, co-author of the study and associate professor at Penn’s School of Arts & Sciences,” the statement said.But what we found, that associated (group) or friendly interactions are also inherited, has not been proven.

Acquired heritage

Juvenile hyenas remain close to their mothers for the first two years of life. Therefore, the social ties of mothers and their young are quite similar in the beginning. However, the researchers noted that even when young people stop spending time near their mothers, they maintain fairly similar social ties with other individuals, especially for women, who typically remain members of the clan for life. “We have data showing that the similarity of social interactions of mothers and their offspring, especially females, was still very high after approximately six years.“Says Amiyaal Ilany, the first author of this paper and researcher at Bar-llan University in Israel. This trend is especially strong for older mothers whose social heritage is strongest in the group. Conversely, children of inferior mothers are less likely to reproduce their mother’s type of social interactions, perhaps trying to make up for their more humble origins by associating with a greater diversity of individuals. “It’s pretty intuitive, things like that happen to people, we inherit social connections, and a lot of social science research shows that it has a huge impact on people’s life paths. ” says Erol Akçay.

Impact on life history

Inheritance of social behavior is a cornerstone of the sustainability of the social structure of the group in the spotted hyena. Indeed, group stability affects the way behaviors are learned and spread within it, but it also ensures a better survival and reproduction rate. The researchers found that young people whose social ties were closest to their mothers lived longer: “If you were born to a lower-ranking mother, you are less likely to survive and reproduce“Erol Akçay testifies. One of the reasons why inheriting social interactions works better for high-ranking hyenas than for lower-ranking ones may be that low-ranking women usually go alone more often to avoid competing with high-ranking ones. Their young men therefore have fewer learning opportunities than high-ranking young therefore there is no social influence for spotted hyenas.



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