Effects of reproductive and social context on vocal communication in captive female African elephants (Loxodonta africana)

Abstract

Female African elephants advertise changes in reproductive condition to males through a variety of modalities, including an increase in low-frequency vocalizations, presumed to travel long distances. Although males respond to these vocalizations, it has been suggested that their proximate function may be to signal to nearby females rather than to distant males. Because elephants live in a female-bonded society, it is likely that changes in female reproductive condition also affect close-range interactions between high- and low-ranking females and that vocalizations may mediate these interactions. To examine female–female interactions related to vocal production and the ovulatory cycle, this year-long study monitored behavior, vocalizations and hormonal cycles for a group of six female captive African elephants at Disney's Animal Kingdom. Rates of several types of close-range interactions were observed to change over the phases of the estrous cycle, and rank seemed to affect whether or not low-frequency vocalizations were given in association with these interactions. Results of this study suggest that a female African elephant's immediate social context and rank in the social hierarchy interact with the hormonal cycle in the production of low-frequency vocalizations, thus many of these vocalizations may not function proximately as signals to distant males, but may be a result of the changing dynamics among females. Zoo Biol 0:1–17, 2005. © 2005 Wiley-Liss, Inc.