A field investigation was conducted to study cold acclimation in the Pitjandjara, a desert tribe of Australian aborigines. Oxygen consumption and rectal and skin temperatures were taken every half hour throughout the night a) while the natives were resting naked on the ground between their camp fires and b) while they rested naked without fires in a single-blanket sleeping bag, subjected to a moderate, but known, cold stress. The air temperature frequently dropped to 0°;C in the early morning. It was found that the camp fires on windless nights could readily supply enough heat to keep both the natives and whites in heat balance throughout the night and resting under basal conditions. In tests with the subjects in light sleeping bags without fires, the natives underwent a considerable peripheral skin cooling, with their foot temperatures dropping regularly to 12°–15°C. They slept soundly through the night with normal resting heat production. The white controls cooled almost as much, but unable to rest, they shivered and thrashed about all night, with a corresponding elevation of metabolism. The cooling adaptation of the Australian aborigines, which resembles the insulative cooling commonly found in mammals, differs from the metabolic compensation and greater peripheral heating developed in cold-acclimated white man.

Submitted on April 18, 1958