Abstract
Human foods have become a pervasive subsidy in many landscapes, and can dramatically alter wildlife behavior, physiology, and demography. While such subsidies can enhance wildlife condition, they can also result in unintended negative consequences on individuals and populations. Seasonal hibernators possess a remarkable suite of adaptations that increase survival and longevity in the face of resource and energetic limitations. Recent work has suggested hibernation may also slow the process of senescence, or cellular aging. We investigated how use of human foods influences hibernation, and subsequently cellular aging, in a large-bodied hibernator, black bears (Ursus americanus). We quantified relative telomere length, a molecular marker for cellular age, and compared lengths in adult female bears longitudinally sampled over multiple seasons. We found that bears that foraged more on human foods hibernated for shorter periods of time. Furthermore, bears that hibernated for shorter periods of time experienced accelerated telomere attrition. Together these results suggest that although hibernation may ameliorate cellular aging, foraging on human food subsidies could counteract this process by shortening hibernation. Our findings highlight how human food subsidies can indirectly influence changes in aging at the molecular level.
Highlights
Human food subsidies, like garbage, crops, and livestock, are a ubiquitous consequence of human development[1,2,3]
We investigated the relationship between food subsidies, hibernation, and cellular aging in the American black bear (Ursus americanus)
We found that the mean monthly rate of telomere change was related to hibernation length; bears that hibernated longer on average experienced a slower rate of telomere attrition or even telomere lengthening during the study (Table 1b, Fig. 1B)
Summary
Like garbage, crops, and livestock, are a ubiquitous consequence of human development[1,2,3]. Shortened hibernation periods are likely to lead to similar mismatches with local food sources and increased interactions and conflicts with humans[11,31] It is unknown what these consequences will have on individual physiology or fitness traits, but given that hibernation is modulated primarily by local food conditions[11,12,30,33], natural food availability and human subsidies could indirectly govern senescence by altering rates of cellular aging. Bears that use areas of human development show decreased hibernation periods[11,30,31] This altered denning chronology is assumed to result from increased consumption of food subsidies, this link has not been directly explored. We examined whether the specific role of oxidative stress associated with hibernation is a potential mechanism mediating telomere length change in bears
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