Feeding success in African wild dogs: does kleptoparasitism by spotted hyenas influence hunting group size?

1. Group hunting in social carnivores is generally thought to have evolved through natural selection for improved efficiency of prey capture, increased prey size apprehended or defence of the kill against intra- and interspecific kleptoparasitism.\ud \ud 2. We used a simple model to explore how variation in hunting group size or wild dogs in the Serengeti influences defence of kills against kleptoparasitism from spotted hyenas and the trade-off effects this has on intake rate per dog for a given prey size selected.\ud \ud 3. The analysis presented suggests that while kleptoparasitism substantially influences the amount of time a hunting group can access a kill, increases in access rime with increased hunting group size rarely fully compensate Cor the reduction in each dog's share of the carcass due to scramble competition among the dogs.\ud \ud 4. A profitability index, which includes limitations of the probability of capturing different sized prey, gut capacity, food depletion and access time, suggests that small hunting groups (1-2) would be particularly vulnerable to kleptoparasitism because they are usable to fully satiate themselves before spotted hyenas take over their kills. Intermediate-sized hunting groups may be most effective at meeting nutritional demands over a range of prey sizes.\ud \ud 5. While reasons for the recent extinction of the Serengeti wild dog population remain speculative, this paper contributes lo the debate by proposing that kleptoparasitism by spotted hyenas would have placed a major constraint on the ability of individual wild dog packs to recover from episodic disasters