Rates of Post-flight Cooling in Sphinx Moths

Effective endothermy depends on the capacity to match rates of heat production and heat loss. Other things being equal, the rate of heat loss of a body is proportional to its surface area, and objects of similar geometry have surface areas that are proportional to the two-third power of their volumes. It is, therefore, not surprising that in both birds and small mammals, rates of weight-specific heat loss are inversely proportional to body weight (Morrison, 1960; Herreid and Kessel, 1967; Lasiewski et al., 1967).