Heat Loss from Ducks' Feet Immersed in Cold Water

Abstract

At temperatures between 0-20.degree. C, heat loss from the feet of mallards was minimal (0.42 kcal h-1). In this temperature range, the metabolic heat production increased with declining temperature by 0.22 kcal h-1.degree. C-1. Below 0.degree. C, heat loss from the feet and metabolic heat production increased substantially. The further increase in heat production (0.22 kcal h-1.degree. C-1) was approximately equal to the increase in heat loss from the feet (0.27 kcal h-1.degree. C-1). The observed increase in blood flow to the feet apparently serves to keep their temperatures above freezing and to prevent freezing damage to the tissues.