Physical description: Ursus Arctos (or brown bear) is among the largest and most powerful of all terrestrial carnivores. They stand 91 to 153 cm (3-5 feet) tall on all fours and 183 to 274 cm (6-9 feet) standing. The average weight of the brown bear depends on its sex and its access to a constant food source. A domestic male brown bear weighs on average about 247 kg (550 lb), while the female weighs on average about 157 kg (350 lb). However, brown bears that live along the coast and have access to a more protein-enriched diet can weigh up to 680 kg (1,500 lb). The fur is usually dark brown, but can vary from black to light blond and in very rare cases to white. Some brown bears located in the Rocky Mountains have long hair along their shoulders and backs with a frosted white appearance, leading to the common name "grizzly bear". Systematics and paleontology: the brown bear is classified in the order of carnivores. This order includes placental mammals; most of which are land animals. Carnivores first appeared about 55 million years ago in the late Paleocene. The Order is traditionally divided into suborders, Pinnipedia and Fissipedia. Although Fissipedia includes all land animals, it is paraphyletic and therefore is not considered a valid taxon. Pinnipeds are interesting because they appear to have evolved from a bear-like terrestrial ancestor. Brown bears are part of the Ursida family and more specifically of the Ursus genus. Brown bears are believed to have evolved from the extinct species Ursus Etruscus, the oldest fossil records of which date back 1.8 million years. Taxonomy research has shown that the brown bear is closely related to the polar bear (Ursus Maritimus). Recent genetic studies have...... half of paper .......Committee on the Status of Endangered Wildlife in Canada (COSEWIC). 1999. Canadian Species at Risk: April 1999. Committee on the Status of Endangered Wildlife in Canada, Ottawa, Ontario, Canada. 17 pp.Hall, E. Raymond. 1984. Geographic variation among brown and grizzly bears (Ursus Arctos) in North America. Natural History Museum. The University of Kansas. Lawrence, KS.McLellan, B.N., Servheen, C. & Huber, D. 2008. Ursus arctos. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. . Downloaded March 06, 2012.McNamee, Thomas. 1984. The Grizzly Bear. NYNational Geographic Society. Brown bear. Accessed March 6, 2012.http://animals.nationalgeographic.com/animals/mammals/brown-bear/