摘要: Several mammalian hibernators have annual cycles of fat deposition and usage. However, at any time a particular level is defended. The can therefore be described as ones set-points for body fat. A programmed change in accounts prehibernation fattening not proceeding maximal possible rates. During the winter phase there anorexia even when food available; reasons are proposed why must lowering if to prolonged hibernation. Control mechanisms underlying some instances weight loss gain birds analysed similar terms. In cyclic programmes such that animals do usually operate close physiological limits. quasi-predictable environment they derive advantages from combined use both homeostatic rhythmic control their levels.