Chemical Profiles of Male African Elephants, Loxodonta africana: Physiological and Ecological Implications

Abstract

This study reports concentrations of testosterone and dihydrotestosterone in both serum and temporal-gland secretions of male African elephants (Loxodonta africana), including ra­ diocollared elephants, and identifies a spectrum of volatile components in the temporal­ gland secretions. Androgens in the serum (testosterone and dihydrotestosterone) were mea­ sured in 111 adult male African elephants, ages 21-40 years, from two national parks in South Africa during several years and seasons. About one-fifth (18.6%) of these mature, male, African elephants exhibited dramatically increased concentrations of testosterone in serum characteristic of male Asian elephants during musth. In Kruger National Park, six radiocollared male African elephants, ages 25-35 years, were tracked and serially sampled for both serum and temporal-gland secretions during a 5-year period. Concentrations of testosterone in serum and temporal-gland secretions were elevated cyclically at times when typical musth behaviors, including aggression, were observed. This study reports the first chemical characterization of the volatile compounds of the temporal-gland secretions from male African elephants in musth. It reveals many similarities between the chemical con­ stituents of the temporal-gland secretions of these male African elephants and the com­ pounds identified in male Asian elephants. In addition, several compounds, not previously identified in temporal-gland secretions of African elephants, are described. Such chemical data support the behavioral observations by ourselves and other researchers that male Af­ rican elephants experience musth. Especially convincing are the concurrent hormonal and chemical data from the radiocollared males during episodic periods of behavioral musth. Implications of the incidence of musth in the past and present ecology of African elephants are discussed in view of the increasing compression within national parks.