Thermoregulatory Adaptations to Starvation in Birds

摘要: Birds have body temperatures that are typically higher than those of mammals, and thus spend a large proportion their total energy budget maintaining these temperatures—particularly in cold environments. also high surface to volume ratios comparatively small reserves causing additional energetic challenges during periods food limitation or complete starvation. During starvation, can be saved if the need for active thermogenesis reduced. Such hypometabolic state achieved by reducing temperature regulated manner increasing thermal insulation, employing both mechanisms. Adaptive changes heat loss (thermal conductance) is well known among birds, but growing number studies documenting how birds able conserve limited manner. Rest-phase hypothermia shallow torpor involve decreases ranging from 1 10°C, with retaining responsiveness environment, whereas deep characterized larger decrease, often approaching ambient resulting true torpidity. Starvation induce some avian groups, notably hummingbirds swifts; however, recent show basically all groups save starvation entering rest-phase daily cycle. So far, such responses been found at least 29 families. This chapter reviews our current understanding alter thermoregulatory patterns face underscores to: (1) investigate neurohumoral underlying (2) better quantify savings ensuing temperature.