Claim: The gray wolf colonized North American at least three times during the Rancholabrean.

The gray wolf or grey wolf -LRB- Canis lupus -RRB- , also known as the timber wolf or western wolf , is a canine native to the wilderness and remote areas of Eurasia and North America . It is the largest extant member of its family , with males averaging 43 - and females 36 - . Like the red wolf , it is distinguished from other Canis species by its larger size and less pointed features , particularly on the ears and muzzle . Its winter fur is long and bushy and predominantly a mottled gray in color , although nearly pure white , red , and brown to black also occur . , 37 subspecies of C. lupus are recognised by MSW3 .   The gray wolf is the second most specialised member of the genus Canis , after the Ethiopian wolf , as demonstrated by its morphological adaptations to hunting large prey , its more gregarious nature , and its highly advanced expressive behavior . It is nonetheless closely related enough to smaller Canis species , such as the eastern wolf , coyote , and golden jackal to produce fertile hybrids . It is the only species of Canis to have a range encompassing both the Old and New Worlds , and originated in Eurasia during the Pleistocene , colonizing North America on at least three separate occasions during the Rancholabrean . It is a social animal , travelling in nuclear families consisting of a mated pair , accompanied by the pair 's adult offspring . The gray wolf is typically an apex predator throughout its range , with only humans and tigers posing a serious threat to it . It feeds primarily on large ungulates , though it also eats smaller animals , livestock , carrion , and garbage .   The gray wolf is one of the world 's best-known and most-researched animals , with probably more books written about it than any other wildlife species . It has a long history of association with humans , having been despised and hunted in most pastoral communities because of its attacks on livestock , while conversely being respected in some agrarian and hunter-gatherer societies . Although the fear of wolves is pervasive in many human societies , the majority of recorded attacks on people have been attributed to animals suffering from rabies . Non-rabid wolves have attacked and killed people , mainly children , but this is rare , as wolves are relatively few , live away from people , and have developed a fear of humans from hunters and shepherds .