THE EFFECT OF WIND AND MOISTURE ON HEAT LOSS THROUGH THE FUR OF NEWBORN CARIBOU

Abstract

The effects of air velocity and direction and of wetness on rate of heat transfer were studied in tests with samples of fur from five caribou calves. The rate of heat transfer through this fur increased by a factor of two to three with increase in air velocity from a negligible level (natural convection) to 23 m/second (direction parallel to sample). The effect of air velocity varied markedly (up to ±50% at 23 m/second) with inclination of the sample to the direction of air movement. Spraying water on the fur increased its rate of heat transfer markedly; addition of water equivalent to 10–12% of the volume of the fur doubled the rate of heat transfer. Other factors, such as erectness of the fur, direction of the hairs or "grain" of the fur with respect to the direction of air movement, and wetness of the skin also affected heat transfer. Differences between samples were large and did not appear to depend directly on the physical characteristics measured.