We have looked at the Pacific environment and the physique of Pacific people. This chapter considers the shaping of the people by this environment.

Biogeographical rules

In terms of morphology, one view of the relationship between any warm-blooded species and its environment is summed up by Damon: ‘Climate … does indeed seem to be the major regulatory factor for … body size and proportion’ (1977: 221). In this statement are subsumed the classical biological rules of Bergmann and of Allen. In 1847 Carl Bergmann, a German physiologist, published ‘The relationship of the conservation of heat in animals to their size’ (‘a very original paper’ noted D'Arcy Thompson), in which he examined the problem of heat loss and heat production. Aware that surface area varies as the square of a body's linear dimensions, whereas mass varies as the cube, Bergmann reasoned that in the same environment a small animal has to produce more heat per unit of mass than does a large animal, in order to keep pace with surface loss: ‘this extra heat production means more energy spent, more food consumed, more work done’ (Thompson 1942:34). Thus we come to such comparisons as that a man may eat one-fiftieth of his body weight in a day whereas in the same time a mouse must eat half its weight, and a warm-blooded animal much smaller than a mouse is an impossibility. The principle Bergmann arrived at explains why, within a warm-blooded polytypic species, those living in cold regions tend to have greater body mass than those living in warm regions.