Abstract

Due to the extreme scasonality of environment caribou undergo dramatic changes in body composition. During winter body growth slows or ceases, total body weight declines, fat reserves are severely diminished or exhausted, and muscle tissue is mobilized to provide energy and protein to vital functions. Seasonal patterns of caribou carcass composition differ according to age and sex. Calves are very lean at birth, remain lean through most of the summer, but by autumn have accumulated considerable fat. By the end of the flirst year fat levels in calves are similar to those of adults. Mature males are fattest in the fall but lose most of their stored fat during the rut and enter the winter in poor condition. Mature females are also fattest in the fall, are affected little by the rut, and enter winter in excellent condition. Despite the energy demands of gestation, pregnant females are often fatter than barren cows and maintain greater fat deposits into spring. At parturition the onset of lactation creates severe energetic demands on the dam and females are in poorest condition in mid summer. Dry cows are fatter at this time. The physiological need for fat in the diet of hunters inhabiting northern. latitudes led to a well documented preference for the fattest animals. Patterns of caribou energetics and carcass composition were likely exploited to yield maximum return of high energy food. Archaeological verification of selective hunting and butchering can be achieved through sexing of bones, determination of seasonality, and probably delineation of the conditions of pregnancy and lactation. An example from the Plains of North America demonstrates a strong correlation between bioenergetics of bison and historic period hunting patterns. It is suggested that a similar correspondence may be found in the Arctic literature.