Although laboratory studies of large mammals have revealed valuable information on thermoregulation, such studies cannot predict accurately how animals respond in their natural habitats. Through insights obtained on ther-moregulatory behavior, body temperature variability, and selective brain cooling in free-living mammals, we show here how we can better understand the physiological capacity of large mammals to cope with hotter and drier arid-zone habitats likely with climate change. © 2014 Int. Union Physiol. Sci./Am. Physiol. Soc.