Why do African elephants (Loxodonta africana) simulate oestrus? an analysis of longitudinal data

Bates, Lucy A, Handford, Rosie, Lee, Phyllis C, Njiraini, Norah, Poole, Joyce H, Sayialel, Katito, Sayialel, Soila, Moss, Cynthia J and Byrne, Richard W (2010) Why do African elephants (Loxodonta africana) simulate oestrus? an analysis of longitudinal data. PLoS ONE, 5 (4). pp. 1-6. ISSN 1932-6203

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Abstract

Female African elephants signal oestrus via chemicals in their urine, but they also exhibit characteristic changes to their posture, gait and behaviour when sexually receptive. Free-ranging females visually signal receptivity by holding their heads and tails high, walking with an exaggerated gait, and displaying increased tactile behaviour towards males. Parous females occasionally exhibit these visual signals at times when they are thought not to be cycling and without attracting interest from musth males. Using demographic and behavioural records spanning a continuous 28-year period, we investigated the occurrence of this ‘‘simulated’’ oestrus behaviour. We show that parous females in the Amboseli elephant population do simulate receptive oestrus behaviours, and this false oestrus occurs disproportionately in the presence of na ̈ıve female kin who are observed coming into oestrus for the first time. We compare several alternative hypotheses for the occurrence of this simulation: 1) false oestrus has no functional purpose (e.g., it merely results from abnormal hormonal changes); 2) false oestrus increases the reproductive success of the simulating female, by inducing sexual receptivity; and 3) false oestrus increases the inclusive fitness of the simulating female, either by increasing the access of related females to suitable males, or by encouraging appropriate oestrus behaviours from female relatives who are not responding correctly to males. Although the observed data do not fully conform to the predictions of any of these hypotheses, we rule out the first two, and tentatively suggest that parous females most likely exhibit false oestrus behaviours in order to demonstrate to na ̈ıve relatives at whom to direct their behaviour.

Item Type: Article
Schools and Departments: School of Psychology > Psychology
Subjects: Q Science > QL Zoology > QL0750 Animal behaviour
Q Science > QZ Psychology
Depositing User: Dr Lucy Bates
Date Deposited: 14 Jun 2018 14:32
Last Modified: 02 Jul 2019 15:31
URI: http://sro.sussex.ac.uk/id/eprint/76505

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