Establishing the presence of a body temperature rhythm in chimpanzees (Pan troglodytes) using a tympanic membrane thermometer

Seven chimpanzees (Pan troglodytes) were trained to present their cars so that a tympanic membrane thermometer could he inserted. Temperatures were collected from both cars of each subject every 3 hours for 72 consecutive hours. The presence of a body temperature rhythm, well documented in other mammals, was established. Each car demonstrated its own rhythm, but the rhythms in both cars generally mirrored each other. Similarities in the temperature rhythms of cagemates were found. These data are the first evidence of a body temperature rhythm in chimpanzees, and they represent a non-invasive method of measuring the 24-hr rhythms in both human and non-human primates.