the females were reported at . The Northwestern wolf is also one of the longest wolf subspecies as his length usually ranges from 5 to 6 ft, and it can also reach as long as 7 ft (213 cm). In comparison, the mean adult weights of its nearest rivals in size, the Eurasian wolf (C. l. lupus) and the Interior Alaskan wolf (C. l. pambasileus), was reported as and , respectively. Sir John Richardson described the northwestern wolf as having a more robust build than the Eurasian wolf, with a larger, rounder head and a thicker, more obtuse muzzle. Its ears are also shorter, and its fur bushier. Reintroduction In Yellowstone National Park, artificially relocated northwestern wolves have been well-documented feeding on elk. They usually stampede the herd using pack teamwork to separate the younger elk from the adults. They also will charge young calves separated from their parents. Winter-weakened or sick elk also play an important part of Yellowstone wolf diets, and it is estimated that over 50 percent of winter-weakened or sick elk in Yellowstone are killed by wolves. Of these, about 12 percent of carcasses were scavenged by other predators, including ravens, bald eagles, black bears, grizzly bears, and coyotes. In the same national park, wolves also prey on bison, though such attacks usually involve sick animals or calves because healthy, adult bison can easily kill wolves with their hooves. Wolves are present in Canadian and British safari parks including Longleat, Woburn, and Parc Omega. References External links Subspecies of Canis lupus Carnivorans of North America Mammals of Canada Mammals of the United States Wolves in the United States Fauna of the Northwestern United States Fauna of Alaska Mammals described in 1829