Data from:Unpredictable warm spells in winter increase blood cortisol level but lengthen telomeres in a seasonal rodent Phodopus sungorus

Animal performance in the environment significantly determines its
fitness. However, global warming and the increased frequency of
unpredictable weather events may disrupt the proper timing of seasonal
adjustments of a phenotype. This may lead to the deterioration of the
animal's condition and shorten its lifespan. We tested whether warm
spells in winter affect the baseline and stress-induced cortisol level and
leukocyte relative telomere length in two winter phenotypes of Siberian
hamster Phodopus sungorus, responding and non-responding to short
photoperiod. We found that both phenotypes increased cortisol levels in
winter and that warm spells augmented this response. Under stable cold
conditions, non-responding individuals were more vulnerable to short-term
stress than responding ones. However, telomere length increased,
suggesting that animals have a high potential to cope with stress and
prevent telomere shortening or that these two variables are not directly
related. In responding individuals, the higher incidence of torpor also
prevented telomere shortening. These results indicate that both
phenotypes, responding and non-responding to short photoperiod, can
overcome the challenges posed by an unpredictably changing environment.