Short-term gland secretion in the African elephant: tourist disturbance or social interactions as source for secretion?

The temporal gland is an organ found exclusively in elephants, located midway between the eye and the ear. Hypotheses exist about what factors lead to the release of the secretion but so far few studies have taken place in the wild, especially of secretion in relation to behaviour. It has been suggested that the secretion serves in communication or that it is a symptom of stress. These hypotheses were tested by observing free-ranging elephants in Etosha National Park, Namibia. Factors considered were the impact of carnivores, of herds of other herbivores, of vehicles and of other elephants on the amount of secretion in focal elephant families. Neither other mammals nor tourists, recorded in terms of vehicles, seemed to affect secretion, but the secretion increased with the rate at which members of elephant families displaced each other. It is concluded that the secretion is predominantly related to social behaviour and less to factors extrinsic to the elephant herd. [ABSTRACT FROM AUTHOR]