Interspecific competition and predation in American carnivore families

Intraguild interactions play a prominent role in shaping ecological communities, so over evolutionary time one might expect that species that co-occur with a large number of competitors would evolve morphological and behavioural adaptations to ameliorate risks of intraguild competition and predation. In four different sets of analyses that took account of habitat stratum, habitat type and activity pattern on competition and predation pressure, significant differences were found in the extent to which American carnivore families potentially encounter other carnivores. Members of largely omnivorous families, Canidae and Ursidae, co-occur with a greater proportion of potential competitors than members of families with more specialized diets. We found that members of the Mustelidae family may reduce competition by being arboreal or aquatic, and that members of the Procyonidae and Mephitidae are potentially under great predation pressure but the former reduce this threat by being arboreal whereas Mephitidae likely reduce predation through advertising noxious secretions. In one analysis, conspicuous species with both contrasting facial and body colouration co-occurred with more potential predators than other less striking species of carnivore suggesting that intraguild predation is an evolutionary driver of contrasting coat colouration in carnivores. These quantitative analyses suggest that several facets of carnivore niche occupation and morphology have evolved in response to intraguild pressures.