- 1Dogs Canis familiaris are the world's most common carnivore and are known to interact with wildlife as predators, prey, competitors, and disease reservoirs or vectors.
- 2Despite these varied roles in the community, the interaction of dogs with sympatric wild carnivore species is poorly understood. We review how dogs have been classified in the literature, and illustrate how the location and ranging behaviour of dogs are important factors in predicting their interactions with wild prey and carnivores.
- 3We detail evidence of dogs as intraguild competitors with sympatric carnivores in the context of exploitative, interference and apparent competition.
- 4Dogs can have localized impacts on prey populations, but in general they are not exploitative competitors with carnivores. Rather, most dog populations are highly dependent on human-derived food and gain a relatively small proportion of their diet from wild prey. However, because of human-derived food subsidies, dogs can occur at high population densities and thus could potentially outcompete native carnivores, especially when prey is limited.
- 5Dogs can be effective interference competitors, especially with medium-sized and small carnivores. Dogs may fill the role of an interactive medium-sized canid within the carnivore community, especially in areas where the native large carnivore community is depauperate.
- 6Dogs can also be reservoirs of pathogens, because most populations around the world are free-ranging and unvaccinated. Diseases such as rabies and canine distemper have resulted in severe population declines in several endangered carnivores coexisting with high-density dog populations. Dogs can therefore be viewed as pathogen-mediated apparent competitors, capable of facilitating large-scale population declines in carnivores.
- 7Based on this information, we propose conceptual models that use dog population size and ranging patterns to predict the potential for dogs to be intraguild competitors. We discuss how interactions between dogs and carnivores might influence native carnivore communities.