Growth, size and the timing of births in an individually identified population of oribi

Authors

  • GWEN JONGEJAN,

    1. **Department of Zoology, University of British Columbia, Vancouver, B.C. V6T IW5, Canada and Serengeti Wildlife Research Institute, PO Box 3134, Arusha, Tanzania
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  • PETER ARCESE,

    Corresponding author
    1. **Department of Zoology, University of British Columbia, Vancouver, B.C. V6T IW5, Canada and Serengeti Wildlife Research Institute, PO Box 3134, Arusha, Tanzania
      *Correspondence author.
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  • A. R. E. SINCLAIR

    1. **Department of Zoology, University of British Columbia, Vancouver, B.C. V6T IW5, Canada and Serengeti Wildlife Research Institute, PO Box 3134, Arusha, Tanzania
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*Correspondence author.

**Correspondence address.

Summary

This paper describes observations on body size, growth, and the timing of births in an individually identified population of oribi (Ourebia ourebi, Zimmermann 1783) in the Serengeti National Park, Tanzania. Females tended to be larger and approximately 2 kg heavier than males. Young oribi grew rapidly, attaining near-adult size in about 7 months. Horns appeared in male oribi at about 4½ months of age and grew rapidly up to 20 months of age. Births occurred in all months of the year but were most common between March and June. The results provide an observational means of estimating the age of sub-adult oribi by body size, and the age of adult male oribi, up to 20 months of age, by horn length.

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