Biochemical detection of fecal hematin as a test for meat eating in chimpanzees (Pan troglodytes)



Meat-eating by wild chimpanzees has been reported by a number of workers during the last two decades. Direct observation probably underestimates the incidence, even though the behavior occurs relatively infrequently. In 1978, Moreno-Black suggested that fecal analysis over a long period of time is probably the most effective means to determine the incidence of this behavior in wild chimpanzees and other nonhuman primate groups. A method currently employed by a number of fieldworkers involves the recovery of the remains of a carnivorous meal in the animal's feces. This method, however, may also under represent the incidence because of (1) complete digestion of mammalian parts, (2) the unidentifiability of partially digested remains, and (3) the reingestion of feces. This paper reports the results of a laboratory study using a fecal test not subject to these limitations. The test is based on the biochemical detection of hematin, a derivative of hemaglobin which is found in all mamalian tissues. The results of this study reveal that hematin is a reliable indicator of meat consumption. The test is available in a commercially prepared kit, namely HEMOCULT™, which was developed to detect clinically significant amounts of blood in the feces of human patients with presumptive gastrointestinal lesions. This kit has been evaluated with a view to its possible application in the field.