Muscular Heat Production in Pigeons During Exposure to Cold

Pigeons were kept at different air temperatures while measurements were taken of the temperatures in various parts of their bodies. At room temperature the abdomen and the pectoral muscles had nearly the same temperature. At –22°C the pectorals stayed one-half to two degrees warmer than the abdomen, which remained the same as at room temperature. Myograms from the pectorals showed a considerable electrical activity in the cold which vanished at room temperature. It is concluded that the increased pectoral temperature reflects an elevated heat production. As the pectorals of a pigeon make up about one-third of the body weight, it is clear that they make a significant contribution to the accessory heat during cold stress.