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Life expectancy, maximum longevity and lifetime reproductive success in female Thornicroft's giraffe in Zambia
- Bercovitch, Fred B., Berry, Philip S. M.
- African journal of ecology 2017 v.55 no.4 pp. 443-450
- Giraffa camelopardalis, adults, breeding, females, gender differences, life history, longevity, males, models, pregnancy, reproductive performance, reproductive success, variance, Zambia
- Gestation and longevity scale with body mass across taxa, yet within size dimorphic taxa, males tend to have reduced lifespans compared with females. Testing life history models, and accounting for sex differences in longevity, requires obtaining accurate longitudinal data from wild populations. We provide the first report describing key life history parameters from a long‐term study of giraffes in Africa. We followed a population of Thornicroft's giraffe (Giraffa camelopardalis thornicrofti) in Zambia for over 40 years. Maximum longevity among females was approximately 28 years, with lifespan accounting for 81% of the variance in lifetime reproductive success. Average adult female life expectancy was no different than average adult male life expectancy. However, the breeding lifespan of males was about half that of females, while maximum lifespan of males was 75% that of females. Our findings support the suggestion that sex differences in maximum lifespan arise from stronger selection for lengthy lives in females than in males. Among females, longer lives are associated with greater reproductive output.