Although cougars also commonly called mountain lions and pumas are typically considered to be numerous in the West, they have in fact been eliminated from about 50 percent of that territory and as much as two-thirds of its North American range. Historically ranging from Chile to British Columbia and east to the Atlantic seaboard, today the cougar has been virtually eliminated east of the Mississippi, and its fate in the West is threatened by increasing habitat loss and fragmentation. Cougars in Texas, the northern Rockies and southern California, for example, have disappeared from much of their former range. Once a vital part of the natural landscape throughout the Rocky Mountains and northern forests in the U.S., the graceful and mysterious lynx is also struggling to survive. While lynx remain in Canada and Alaska, only a sparse number now exist in Maine, Montana, Wyoming, Washington and Colorado.
Habitat loss poses the single biggest threat to cougars in the West.
Cougars require significant areas of wild land to establish home ranges and permit their young to disperse. Cougar home ranges typically vary from 25 to 500 square miles for males, and from eight to 400 square miles for females. Increased suburban expansion into cougar habitat is the main cause of habitat loss and fragmentation for western cougars. New suburban developments shrink cougar habitat and create habitat islands, placing a greater number of cougars in close contact with humans and increasing the chances for cougar-human encounters, which can result in harm to humans or the eventual destruction of cougars. Roads to accommodate suburban growth also present significant threats by preventing cats from dispersing and increasing cougar deaths due to vehicles.