Thermal ecology, environments, communities, and global change: Energy intake and expenditure in endotherms

To survive, animals must maintain a balance between energy acquisition (foraging) and energy expenditure. This challenge is particularly great for endotherm vertebrates that require high amounts of energy to maintain homeothermy. Many of these endotherms use hibernation or daily torpor as a mechanism to reduce energy expenditure during anticipated or stochastic periods of stress. Although ecological researchers have focused extensively on energy acquisition, physiologists have largely studied thermal ecology and the mechanisms allowing endotherms to regulate energy expenditure, with little research explicitly linking ecology and thermal biology. Nevertheless, theoretical considerations and research conducted so far point to a significant ecological role for torpor in endotherms. Moreover, global-change challenges facing vertebrate endotherms are also considered in view of their ability to regulate their energy expenditure. We review the thermal ecology of endothermic vertebrates and some of its ecological and evolutionary implications. ©