Chuck Bednar for redOrbit.com – @BednarChuck
By studying spotted hyenas in Kenya, a team of researchers from the Michigan State University have discovered that an animal’s place in society can impact its overall health, according to new research appearing in the latest edition of the journal Biology Letters.
Co-lead author Nora Lewin, a doctoral student in zoology at MSU, and her colleagues examined the influences of same-group dominance rank and group membership on telomere length in wild adult spotted hyenas (Crocuta crocuta). Telomeres, they explained, are important biomarkers of the aging process, and can also provide details about how stress acts at the cellular level. These are the end caps on DNA strands that prevent deterioration of chromosomes.
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They found that high-ranking hyenas exhibited significantly greater mean telomere length than those viewed as subordinates, and that membership to a group served as a significant predictor of mean telomere length within higher-ranking females. They were unable to link the availability of prey to this phenomenon, and also found that age did not accurate predict telomere length.
Higher-ranking hyenas live longer
“High-ranking members in hyena clans reproduce more, live longer, and appear to be in better overall health. 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.” Lewin, who was joined on the study by co-lead author and MSU zoologist Kay Holenkamp, explained in a statement.
Curious to see if telomeres would support her observations, Lewis joined an ongoing hyena experiment run by Holekamp. This granted her access to over a quarter-century’s worth of data and allowed her to spend a summer in Kenya, observing the social structure of the creatures first-hand.
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The researchers found that higher-ranking hyenas had longer telomeres than their subordinates, and that group membership significantly predicted the length of these biomarkers in those female hyenas that resided atop the social pyramid. Shrinking telomeres, they explain, signify that a cell is shifting into defense mode and indicate that it (and its host organism) may soon die.
“This work shows, for the first time, the effects of social rank on telomere length in wild mammals,” explained Lewin. “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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The research also revealed some surprises, she explained. While the alpha females of each clan consistently had the longest telomeres of the group, the actual length of those biomarkers varied from clan to clan. In other words, if scientists found a single hyena wandering the savannah, they would not be able to identify if it was an alpha based solely on telomere length.
Furthermore, they were able to eliminate some factors that might have had an effect on telomere length, including the abundance of food. Since the availability of prey did not influence the size of telomeres, Lewin said, it means, “there are other factors we need to find.”
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