of dogs across the Bering Strait 12,000 to 14,000 years ago. Research into the inheritance of white colour from dogs into wolves has yet to be undertaken. Ecology Distribution and habitat Wolves occur across Eurasia and North America. However, deliberate human persecution because of livestock predation and fear of attacks on humans has reduced the wolf's range to about one-third of its historic range; the wolf is now extirpated (locally extinct) from much of its range in Western Europe, the United States and Mexico, and completely in Ireland, the United Kingdom, and Japan. In modern times, the wolf occurs mostly in wilderness and remote areas. The wolf can be found between sea level and . Wolves live in forests, inland wetlands, shrublands, grasslands (including Arctic tundra), pastures, deserts, and rocky peaks on mountains. Habitat use by wolves depends on the abundance of prey, snow conditions, livestock densities, road densities, human presence and topography. Diet Like all land mammals that are pack hunters, the wolf feeds predominantly on wild herbivorous hoofed mammals that can be divided into large size and medium size , and have a body mass similar to that of the combined mass of the pack members. The wolf specializes in preying on the vulnerable individuals of large prey, with a pack of 15 able to bring down an adult moose. The variation in diet between wolves living on different continents is based on the variety of hoofed mammals and of available smaller and domesticated prey. In North America, the wolf's diet is dominated by wild large hoofed mammals (ungulates) and medium-sized mammals. In Asia and Europe, their diet is dominated by wild medium-sized hoofed mammals and domestic species. The wolf depends on wild species, and if these are not readily available, as in Asia, the wolf is more reliant on domestic species. Across Eurasia, wolves prey mostly on moose, red deer, roe deer and wild boar. In North America, important range-wide prey are elk, moose, caribou, white-tailed deer and mule deer. They also prey on bison and muskoxen. Wolves can digest their meal in a few hours and can feed several times in one day, making quick use of large quantities of meat. A well-fed wolf stores fat under the skin, around the heart, intestines, kidneys, and bone marrow, particularly during the autumn and winter. Nonetheless, wolves are not fussy eaters. Smaller-sized animals that may supplement their diet