The small and mid-sized carnivores (Carnivora), or mesocarnivores of western forests comprise 16 species (coyote (Canis latrans), red fox (Vulpes vulpes), gray fox (Urocyon cinereoargenteus), ringtail (Bassariscus astutus), raccoon (Procyon lotor), marten (Martes americana), fisher (M. pennanti), ermine (Mustela erminea), long-tailed weasel (M. frenata), mink (M. vison), wolverine (Gulo gulo), northern river otter (Lontra canadensis), western spotted skunk (Spilogale gracilis), striped skunk (Mephitis mephitis), Canadian lynx (Lynx canadensis), and bobcat (Lynx rufus)). The term “forest carnivores” denotes a smaller group of four species – the marten, fisher, lynx, and wolverine – and is only marginally descriptive, inasmuch as it excludes many carnivores that live in forests, and includes the wolverine, which can thrive in the complete absence of trees. The species we consider here represent four (or five (Dragoo and Honeycutt 1997)) taxonomic families and are characterized by adult body weights typically <20 kg. Other mesocarnivores, including the kit fox (Vulpes macrotis), swift fox (V. velox), least weasel (Mustela nivalis), black-footed ferret (M. nigripes), and badger (Taxidea taxus), occur in the West, occupy habitats near forest edges, and may be conservation concerns. However, they are plains or grassland specialists or, in the case of the least weasel, very poorly known, and cannot be characterized in terms of their needs for forest attributes. So, they are not treated here.
Our understanding of the ecology of carnivores in western coniferous forests varies markedly.