![]() Dandelion flowers Taraxacum officinalis were used as bait to maximize capture probability. A total of 20 Tomahawk’s traps were located within the study area and kept open each day from 08:00 to 20:00 h. Hair samples were collected during marmot captures, conducted in 2019, from 6 to 16 June, when marmots emerged from the burrows after hibernation. Hence, if not considered, such diversely influencing factors may confound results when using HCC as biomarker of chronic stress with regard to a specific research question or when comparing individuals or populations (Heimbürge et al. ![]() Likewise, in humans, men show generally higher HCCs, but simply for physiological reasons, namely a lower activity of glucocorticoid-metabolizing enzymes in men (Raven and Taylor 1996). In chacma baboons, higher HCCs in males were related to social stress, caused by the comparably high social instability of male hierarchies (Bergman et al. 2013) or Canada lynx Lynx canadensis (Terwissen et al. 2013), chimpanzees Pan troglodytes (Yamanashi et al. 2005) or humans Homo sapiens (Raven and Taylor 1996), but not Asiatic black bears Ursus thibetanus (Malcolm et al. 2011), chacma baboons Papio hamadryas ursinus (Bergman et al. 2015), polar bears Ursus maritimus (Bechshøft et al. Sex, for example, affects HCC in American black bears Ursus americanus (Lafferty et al. However, their effects on HCC are inconsistent across species and may be caused by different mechanisms (Heimbürge et al. 2016), or even features of the hair itself such as hair color (Yamanashi et al. Hair cortisol levels were found to vary with sex (Lafferty et al. HCC is influenced by multiple factors of different origin-internal, external, physiological, and environmental. CORT, however, can also be traced in other samples, such as hair or feathers (Sheriff et al. Although, in principle, they may allow researchers to investigate chronic stress, this requires repeated sampling (Meyer and Novak 2012), which may be challenging due to time and field constraints. These, however, reflect hormone levels over short time periods (e.g., from a few minutes or hours-blood and saliva-to a few days-feces), and their application is restricted to the assessment of acute stress. ![]() CORT can be traced in well-established matrices such as blood, saliva and feces (Sheriff et al. This allows individuals to adequately cope with the stressor (Sapolsky et al. Once released, CORT stimulates the mobilization of energy through glucogenesis while downregulating other life-sustaining functions that do not immediately contribute to survival, such as immunocompetence, growth or reproduction (Möstl and Palme 2002). In response to a stressor, CORT is secreted trough activation of the hypothalamic–pituitary–adrenal (HPA) axis. Stress can be measured using glucocorticoids (GCs) and, more precisely cortisol (CORT) in most mammals, as biomarkers (Sapolsky et al. Although further work is needed to entangle possible mechanisms underlying the neuro-endocrinological modulation on HCC, our results emphasize that determinants such as sex and body temperature in Alpine marmots should be accounted for, when using HCC as marker of chronic stress. Interestingly, body temperature was also positively related to HCC, possibly hinting at individual short- and long-term stress reactivity as part of coping styles. This might be related to sex-specific variation in social stress or resulting from physiological difference, e.g., in baseline and stress-induced levels of cortisol secretion. We found marked sex difference in HCC, with higher levels in females. ![]() We tested the relationship of sex, age class, physical condition and body temperature with the hair cortisol concentration of free-ranging marmots. Here, were explore potential determinants of HCC in the Alpine marmot Marmota marmota. Interpreting HCC values, however, is challenging, because they are determined by the interplay of multiple factors. Hair integrates cortisol over long time periods within a single sample and it can be collected non-invasively, which makes its use particularly interesting for wildlife studies. Hair cortisol concentration (HCC) has recently gained popularity as an easy-to-measure biomarker of long-term stress in wild and domestic animals.
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