The Vascularity and Possible Thermoregulatory Function of the Horns in Goats

Abstract

RING a series of experiments on the Toggenburg goat (Capra hircus), it was noted by Dr. J. R. Pappenheimer that the temperature of the horns of these animals varied greatly. This observation is indicative of a good blood supply which would seem to be a liability in animals that use their horns in combat. Since only a few general descriptions of the vascular morphology of horns are available (Taylor, 1963), the present paper investigates in detail the vascularity of the goat horn and its physiological control. Scholander et al. (1950) have emphasized the importance of extremities in temperature regulation in animals whose bodies are heavily insulated. A highly vascular, bare extremity can serve as an avenue of heat loss when the animal is overheated. Experiments are reported here which evaluate the extent to which the vascularity of the horn contributes to the regulation of body temperature in goats. In addition, evidence is presented which indicates that the circulation of this work is a portion of a Ph. D. thesis submitted to the Department of Biology, Harvard University, Cambridge, Mass. I wish to thank Dr. Charles P. Lyman for his advice, help, and careful scrutiny of the data and manuscripts. It was the observation of Dr. JR Pappenheimer which gave rise to this study, and I have relied on him both for help and advice. I am grateful to Dr. DW Fawcett for providing me with space and facilities in the Department of Anatomy at Harvard Medical School and to the staff of his department for their help and interest.