The ability to maintain a (relatively) stable body temperature in a wide range of thermal environments by use of endogenous heat production is a unique feature of endotherms such as birds. Endothermy is acquired and regulated via various endocrine and molecular pathways, and ultimately allows wide aerial, aquatic, and terrestrial distribution in variable environments. However, due to our changing climate, birds are faced with potential new challenges for thermoregulation, such as more frequent extreme weather events, lower predictability of climate, and increasing mean temperature.
Thermoregulation in Malayan sun bears is not fully understood. Therefore, in this study the effect of meteorological variables on both behavioural and autonomic thermoregulatory mechanisms in sun bears was examined in order to identify temperature thresholds for the activation of various thermoregulatory mechanisms. Infrared thermography was used to non‒invasively determine body surface temperature (TS) distribution in relation to ambient temperature (TA) and to determine the thermoneutral zone (TNZ) of sun bears.
Climate change will expose mammals to an array of stressors, some new, and some with increased frequency and severity. Those stressors influence endocrine and metabolic function, with potential consequences for the survival and persistence of mammalian species. Here, we review the similar consequences of climate change on the physiological function of terrestrial mammals, including direct effects of increasing air temperatures and reduced water availability, as well as the indirect effect of reduced or unpredictable food supply.
