Your Mom's Friends Matter When You're a Spotted Hyena Cub

For spotted hyenas, it’s not strength and size that dictate a cub’s success in life. Instead, it’s all about who your mother knows.

Maternal friendships and their spot in society are important to health and longevity—not just for the adult hyena but for her offspring, a new study finds.

While in other species, physical traits are much more critical to an animal’s survival, for the hyena it’s the mother’s social network, which is inherited by her cubs.

"There are a lot of species where genetic inheritance to be bigger and stronger allows an animal to dominate, but that doesn't happen in hyena society," says study co-author Kay Holekamp, behavioral ecologist and professor at Michigan State University. "We see tiny cubs dominating great huge males, so we know body size is not a good predictor of who will be socially dominant in spotted hyenas."

The study was based on 27 years of Holekamp’s observational data on spotted hyena social networking. She has been studying how these social networks are created, as well as how long they last and what impact they have on a hyena’s life path.

“Hyena society is exactly like baboon society except that females dominate males among hyenas,” Holekamp tells Treehugger. “Mom's friends function as allies in disputes over food, etc.”

Having many friends with high-ranking status is key to a female hyena’s place in the system.

“Having few allies makes it virtually impossible to improve one's status in hyena society,” Holekamp says.

For the paper, the researcher tracked hundreds of hyenas and determined which ones spent time with each other for how long and how closely. They combined this information with social evolution models developed by Holekamp’s study colleagues.

Their findings are published in the journal Science.

Friends and Longevity

Researchers found that hyena cubs become friends with their mother’s closest allies very early in life.

"We knew that the social structure of hyenas is based in part on one's rank in the agonistic hierarchy, which we know is inherited from mothers," says co-authors Erol Akcay, associate professor at the University of Pennsylvania. "But what we found, that affiliative, or friendly interactions are also inherited, hadn't been shown."

These networks are the same early on because hyenas stick so closely to their mothers’ sides for about the first two years of their lives. But the researchers found that even after that, they continued to keep the same alliances. This was especially true for female hyenas who kept with the group for their entire lives.

They found that mother-offspring pairs with similar “friends” or social networks lived longer.

"One explanation for why inheritance of social networks works better for high- than low-ranking hyenas may be that low-ranking females tend to go off on their own more often to avoid competition with higher-ranking hyenas, so their cubs have fewer learning opportunities than cubs of high-ranking females," Holekamp says.

"This shows the beauty of the hyena's fusion-fission society. The low-rankers can make the best of a bad situation by using separation to get away from their competition."