Search for: All records

Monitoring health status is a critical aspect of primate conservation, yet can be difficult to noninvasively investigate in the wild. Because mammals are endothermic, body temperature can be used as a health marker for primates. Using a method previously tested on chimpanzees and humans, we estimated body temperature of wild Bornean orangutans by measuring the internal temperature of fecal samples. Upon quickly collecting a fecal sample after defecation, we recorded internal temperature of the sample at 20-sec intervals for six minutes. Data included a series of temperatures for each sample that we fitted to a sigmoid curve, which was used to estimate body temperature. Estimated body temperature was not affected by sex (F(2,92)= 0.431, P= 0.651), weather (F(2,92)= 1.175, P= 0.313), or collection time (r= -0.074, N= 95, P= 0.468). Estimated body temperature was higher for fecal samples that fell from lower estimated heights (r= -0.23, N= 95, P= 0.0004) and were heavier (r= 0.23, N= 75, P= 0.0475). We compare these results from the field to captive fecal samples, taking place on the ground, to determine the accuracy of this field method. From our field samples (N=95), orangutans appear to have a lower internal body temperature (33.44 ± 1.74 °C) on average than either chimpanzees or humans. Previous studies have demonstrated that orangutans have a lower metabolic rate than other great apes. Lower body temperature may serve as a metabolic adaptation of orangutans to survive extended periods of low food availability when energy needs to be conserved.