POSTNATAL-GROWTH AND SUSTAINED LACTATIONAL EFFORT IN THE AARDWOLF - LIFE-HISTORY IMPLICATIONS

1. Earlier life-history studies suggested that the mammalian iteroparo us/semelparous gradient may be particularly important in shaping patte rns of post-natal development in the hyaenids. Apparent anomalies betw een Aardwolf metabolic rates and post-natal development patterns are i nvestigated. 2. Age-specific post-natal growth in the Aardwolf support s sexual size monomorphism in the species and no statistical differenc e in goodness of fit was evident among various growth curves. Neverthe less, the Gompertz equation consistently provided the better fit and i s recommended. 3. Significant seasonal trends in adult body weights we re evident with low weights at the end of winter (August). Seasonal ad justment of growth data failed to improve the goodness of fit of growt h curves. 4. Asymptotic weight is approached by 1.8 years of age but m ay be reached as early as 3.6 months by some individuals. Maximum grow th rate is achieved at 3 months of age. 5. The power coefficient (c) w hich scales growth between birth and independence is 0.61, and falls b elow the mean value of 0.81 for carnivores. 6. However, previous life- history analyses and the implementation of the Charnov (1991) model su ggests that the Aardwolf has an above average weight and a below avera ge age at maturity. In addition, this species reached final weight bef ore sexual maturity, an uncharacteristic feature for mammalian species . 7. This peculiar suite of life-history characteristics suggests that the Aardwolf tends towards an iteroparous life style, which serves to reduce juvenile mortality. However, species-specific constraints do n ot allow it to pursue this strategy by maximizing growth rate. Instead growth is sustained using an extended lactation period and intensive parental care to enable final body size to be reached as soon as possi ble. 8. These results not only suggest that the adoption of a universa l growth power coefficient (c) to model mammalian life histories is un realistic but also that c should also be interpreted within the broade r context of the complete suite of species specific life-history const raints and characteristics.