Periods of Nutritional Stress in the Annual Cycles of Endotherms: Fact or Fiction?

Abstract

An animal's nutritional status depends on (1) nutrient accessibility, (2) nutrient demand, and (3) physiological, metabolic, morphological, and behavioral compensations that avert or minimize discrepancies, if any, between the first two. The main thesis of this essay is that the diversity and potency of such compensatory mechanisms have often been underrated, and hence the frequency and intensity of nutritional stress in free-living animals have often been exaggerated. This theme is explored in conjunction with an inventory of the modes of compensation for actual or potential dietary deficiencies.