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Résumé :
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The captive southern white rhinoceros (Ceratotherium simum simum) population is not self-sustaining. Many founders reproduced, but reproduction among captive-born (F(1)) females has been extremely sluggish. Thus the conservation breeding program for this species faces a looming crisis. Using behavioral observations of a large captive population and a questionnaire survey circulated to facilities worldwide, several hypotheses for F(1) female reproductive failure were evaluated. Counter to predictions regarding behavioral deficiency in sociosexual behaviors, F(1) females were at least as proficient as F(0) females for all behavioral measures. Males also showed no sociosexual preferences for F(0) over F(1) females. Results indicate that most reproductive failure occurs post-copulation. The reigning root-cause hypothesis for F(1) female reproductive failure postulates that F(0) females are behaviorally dominant and suppress reproduction in F(1) females. However, no evidence for behavioral dominance was found and F(1) females housed with F(0) females were more likely to reproduce than those housed without F(0) females. Such social facilitation of reproduction is beneficial to F(1) female reproduction, but does not explain differential reproduction between F(1) and F(0) females. Because the design controlled for current conditions, these results point to development in captivity as the root cause of postcopulatory reproductive failure in F(1) females. (c) 2005 Elsevier Ltd. All rights reserved.
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