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

Seven chimpanzees (Pan troglodytes) were trained to present their ears so t hat a tympanic membrane thermometer could be inserted. Temperatures were co llected from both ears of each subject every 3 hours for 72 consecutive hou rs. The presence of a body temperature rhythm, well documented in other mam mals, was established. Each ear demonstrated its own rhythm, but the rhythm s in both ears generally mirrored each other. Similarities in the temperatu re rhythms of cagemates were found. These data are the first evidence of a body temperature rhythm in chimpanzees, and they represent a non-invasive m ethod of measuring the 24-hr rhythms in both human and non-human primates.