Wild dogs and kleptoparasitism: Some misunderstandings

Seventeen years ago, we published a landmark paper on the energy expenditure of the African Wild dog (Lycaon pictus) (Gorman et al., 1998) using isotope elimination methods that enable quantification of free-living energy demands (Speakman, 1997). Using these data, we mathematically modelled the energy budgets of wild dogs to show that losses of food to kleptoparasites (lions and hyaenas), while apparently small, lead to an exponential increase in both the required hunting time, and daily energy demands. An increase in kleptoparasitism to 25% of kills would require more than 12 h of hunting per day, and would therefore be unsustainable. This showed why wild dogs are particularly vulnerable to local extinction in areas where their main kleptoparasites are abundant. Jongeling & Koetsier (2014) present a critique of our paper, coming to the contrary conclusion that wild dogs are not vulnerable to kleptoparasitism. Their argument is that we made an error in our calculations because we assumed that without kleptoparasitism wild dogs are in energy balance. From this assumption, we calculated the impact of kleptoparasitism using a simple mathematical model. Jongeling & Koetsier (2014) replicated and validated this calculation in their paper, and hence do not dispute that the model is correct. Their criticism instead lies in our parameterization. A critical value in the model is the energy return from hunting. Because dogs expend 15.3 MJ day−1 and are active for on average 3.45 h day−1, then the average return is 4.43 MJ h−1 hunting. In contrast, Jongeling & Koetsier (2014) suggest that wild dogs catch substantially more than this because they also need to feed attendant pups and that wild dogs routinely eat substantially more than their energy requirements. We will consider each of these arguments in turn