Hyenas at top of social ladder live longer

"If you want to see the hierarchy of spotted hyenas, throw down some fresh meat near them," says Nora Lewin. "It's quickly apparent who's dominant and who's not." (Credit: Rohit Varma/Flickr)

When it comes to aging, social status has its privileges—if you’re a hyena.

Researchers studying spotted hyenas in Kenya focused on telomeres, the caps at the end of each strand of DNA that protect chromosomes from deterioration.

These biomarkers are regarded as important signs of aging and stress in many species, including humans. Shrinking telomeres are a signal that cells are sliding into defensive mode, stressful actions that could soon lead to cells’—and to the organism’s—death.

Hyena hierarchy

“High-ranking members in hyena clans reproduce more, they live longer, and appear to be in better overall health,” says Nora Lewin, doctoral student of zoology at Michigan State University and co-lead author of the study that is published in the journal Biology Letters.

“If you want to see the hierarchy of spotted hyenas, throw down some fresh meat near them. It’s quickly apparent who’s dominant and who’s not.”

The research shows that high-ranking hyenas have longer telomeres than their subordinates. Group membership significantly predicted telomere length of those female hyenas that resided atop the social pyramid.

Alpha females

“This work shows, for the first time, the effects of social rank on telomere length in wild mammals,” Lewin says. “This enhances our understanding of how social and ecological variables may contribute to age-related declines of hyenas, and in organisms in general.”

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Researchers also noticed some interesting twists: the alpha females of each clan had the longest telomeres. But, the length was relative to each individual clan. So a lone hyena wandering in the savanna couldn’t be identified as an alpha female based solely on telomere length.

Also, the abundance or lack of food—a seemingly obvious factor for overall health—didn’t influence the size of the biological marker.

“The fact that there is variation in telomere length when prey abundance is constant means that there are other factors we need to find,” Lewin says. “We think it’s less about genetics and more influenced by the environment, but we just need to keep searching for the right environmental factors.”

Researchers from Cornell University and Bucknell University contributed to the study.

Kay Holekamp, professor of zoology, is co-lead author of the study. The National Science Foundation and the National Institutes of Health funded the work.

Source: Michigan State University