Term of Award

Summer 2006

Degree Name

Master of Science in Biology (M.S.)

Document Type and Release Option

Thesis (open access)

Department

Department of Biology

Committee Chair

Bruce A. Schulte

Committee Member 1

Alan W. Harvey

Committee Member 2

James M. Hutcheon

Committee Member 3

Michelle L. Zjhra

Abstract

Like many polygynous mammals, African elephants exhibit social dimorphism in which females reside in matriarchal groups while males often travel alone or in bachelor groups. Males search for receptive mates who may advertise their condition through chemical and other signals. The difference in adult lifestyles suggests that the developmental pattern of communication for the two sexes should diverge when the social environment and reproductive opportunities of males and females begin to differ. In this study, I examined the differences between the sexes and across four age classes (calves, juveniles, subadults and adults) in the performance of chemosensory behaviors. African elephants were studied at a waterhole in 2004-5 at Ndarakwai Ranch, Tanzania. I identified 277 elephants and 26 distinct female-offspring groups. Sex differences in the chemosensory repertoire and rate of behaviors were evident for subadults but not for the younger age classes. Males showed a higher rate of chemosensory behaviors than females and adults performed chemosensory behaviors more often than calves. Chemosensory responses to a standard stimulus increased in each subsequent age class for males, but showed no age class differences for females. The observed responses supported the hypothesis that chemical communication patterns would diverge during early puberty, indicating that the development of chemosensory behaviors occurs differently in the sexes in preparation for their disparate adult lifestyles.

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