Breeding and juvenile survival among slender-tailed meerkats (Suricatu suricatta) in the south-western Kalahari: ecological and social influences

Reproductive success of co-operatively-breeding slender-tailed meerkats ( Suricata suricatta ) in the Kalahari was monitored over four breeding seasons and 26 band years, concentrating on three focal bands. Breeding was strongly seasonal, with peak numbers of births coinciding with maximum rainfall between January and March. Breeding seasons were extended, and more litters were produced, during the years with above average rainfall. For dominant females, the mean annual rate of litter production was 1.9 ± 0.8 litters per year and short interbirth intervals (mean = 90 %pL 18 days) indicated that females came into oestrus within three weeks of giving birth. Births were synchronous within but not between bands. Major known causes of kitten mortality were cold weather and predation, and losses mainly occurred between three and five weeks of age. Sixty-seven percent of juveniles survived between emergence from the den at three or four weeks old and attainment of effective foraging independence at 12 weeks. There were no significant effects of birth date within the season upon litter size or survival. Several incidents of apparent infanticide were recorded. These meerkats were highly co-operative and adult band members assiduously guarded and provisioned the kittens. Nevertheless, regression analysis showed that neither rainfall (an index of prey availability) nor band size variables accounted for much variance in juvenile survival to 12 weeks, which appeared to be heavily influenced by chance events such as flash floods. In contrast, rainfall between January and March had a significantly positive effect on the total number of juveniles produced during the breeding year.