Reproductive evaluation of elephants culled in Kruger National Park, South Africa between 1975 and 1995

To reduce elephant densities and preserve biological diversity, 14,629 elephants were culled from Kruger National Park, South Africa (1967-1999). Data were catalogued between 1975 and 1996 on 2737 male and female elephants, including pregnancy and lactational status for 1620 females (>= 5 years of age) and, uterine and/or ovarian characteristics for 1279. This study used these data to investigate the effects of age and precipitation on reproduction. The youngest age of conception was 8 years (n = 6) and by 12 years of age all females were sexually mature. From the age of 14 years, the percentage of reproductively active females (pregnant and/or lactating) was > 90%; however, this percentage declined when females reached 50 years of age. Overall, one-tenth of females were nonreproductive (not pregnant or lactating) at any given time, mostly in the youngest (< 15 years) and oldest (> 50 years) age classes. Eighteen (3.3%) of the nonpregnant females had reproductive tract pathologies, including endometrial, uterine or ovarian cysts. There was a seasonal distribution of mating activity that correlated with the rainy season. As has been demonstrated in other populations of free-ranging African elephants, most of the females in Kruger National Park were reproductively active; however, age and climate affected reproductive activity.