Electrocardiographic technique for studying olfactory response in the rock hyraxProcavia capensis L. (Mammalia: Hyracoidea)

Rock hyraces were exposed to the dorsal gland and urinary odors' of conspecifics in a test chamber constructed such that electrocardiographic biopotential could be picked up through the plantar surfaces of the feet. Both heart rate acceleration and deceleration were observed. Female hyraces responded more strongly to odors than males, but no reponse was observed towards the odor of the dorsal gland of sexually inactive males. Electrocardiography allows a more sensitive measurement of response to odor stimuli than has hitherto been reported, and the technique may have a wide applicability in studies on other mammalian species with naked foot soles.