Food, family and female age affect reproduction and pup survival of African wild dogs

Abstract

Understanding factors that affect the reproductive output and growth of a population of endangered carnivores is key to providing information for their effective conservation. Here, we assessed patterns in reproduction for a small population of endangered African wild dogs (Lycaon pictus) over 90 pack years. We tested how availability of prey, pack size, pack density, rainfall, temperature and female age affected the age of first litter, litter size and pup survival. We found that females bred younger when pack density, availability of prey and pack size were large. We also found that fecundity increased significantly with age while the population was male biased only for 1-, 2- and 4-year olds. Larger litters were produced by larger packs, suggesting strong reproductive benefits of grouping related to cooperative hunting and food provisioning for helpers and alpha females. We also found an interaction between breeding female age and pack size where older females in large packs raised a high proportion of pups. Additionally, large litters and large packs were important for raising a greater number of pups to 6 and 12 months, respectively, suggesting that while litter size is important for pup survival, the benefits of a large pack are only realised when pups are older and mobile with the pack. Collectively, these results illustrate the novel finding that prey availability is critically important in initiating reproduction in wild dogs and that the number of non-breeding helpers, female age and litter size is essential to pup survival. Variation in socio-environmental conditions strongly affects reproduction. We studied how the temporal variation in such conditions affected reproduction for African wild dogs across 23 years. We specifically aimed to test how long-term variation in food supply in conjunction with various socio-environmental conditions affected this endangered species’ ability to reproduce and raise offspring. Our result of larger groups producing larger litters and raising more pups strengthens previous conclusions of the critical importance of group size for wild dogs. However, reproduction is strongly dependent on when individuals can first reproduce and, for the first time, we illustrate that prey availability is the lynchpin upon which reproduction is initiated in this endangered species. We also highlight the importance of maternal age and initial large litter sizes in raising pups.