IUCN / SSC Cat Specialist Group - Digital Cat Library |
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| Smuts, G.L.; Hanks, J.; Whyte, I.J. | |
| Reproduction and social organization of lions from the Kruger National Park | |
| 1978 Carnivore (1): 17-28 | |
Reproduction in male and female lions from the Kruger National Park is examined by utilizing material taken from cropped animals and observation made in the field. Subadult males emigrate from the parent group between 27 and 36 months of age while females could either remain in the parent group or emigrate as early as 24 months. All pride males (n=18) were between 5 and 9 years old (mean age= 6.5 years) and no males under 5 years of age associated sexually with adult females. All male lions under 26 months of age were sexually immature, the median age at maturity being 30 months. Female lions reached sexual maturity at between 43 and 66 months of age (mean=48 months) and all lionesses over 5.5 years of age had previously ovulated. Twenty percent of all parous lions (n=60) were pregnant, 21.7% were lactating, i.e., had cubs < 9 months old, 51.7% were non-lactating with or without offspring > 24 months old, and 6.7% were sterile. At least 94.7% of all ovulations preceding pregnancy were fertile. Luteinisation of unruptured follicles was found to occur in two pregnant lions, and one pregnant lion out of 12 was found to have resorbed one of her embryos while the other embryo was normal. Lactation lasts for 8 to 9 months and the corpus luteum of preganancy remains visible for about 1 month post partum. Corpora albicantia and ovulation scars (points) remain visible for considerable periods of time depending on the reproductive state of the female. All females with large cubs were in anestrus (limited ovarian activity). The two oldest females still capable of reproduction were 12 and 13 years old. Mean ovulation rate and litter size were both 3.08 (range=1-5). Mean litter size for cubs < 12 months old was 3.02 (range=1-4; n=47 litters) and for cubs 13 to 24 months was 2.71 (n=7 litters). Most litters of lion cubs are born during the period when the major prey animals of the lion produce their young. Estrus and birth synchronization within social groups were common and some of the possible causes are discussed. No definite cases of pseudopregnancy were found during the study, and it is suggested that the high incidence of reproductive failure reported for wild lions may be due to anovulatory estrous cycles. |
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