Mule deer and white-tailed deer are similar in size and appearance. Their color varies with the season but is generally light brown in summer, turning dirty gray in winter. While both species are considerably smaller than elk, the mule deer is a little stockier than the white-tailed deer. The mule deer has a white rump, a white tail with a dark tip, and large mulelike ears. It inhabits open forests along valley floors. Waterton town site has a healthy population of mule deer. The white-tailed deer’s tail is dark on top, but when the animal runs, it holds its tail erect, revealing an all-white underside. Whitetails frequent thickets along the rivers and lakes of the foothills. They are most common on the British Columbia  side of the Continental Divide.
The elk, or wapiti, is the most widespread and common of the larger mammals living in the Canadian Rockies . It has a tan body with a dark-brown neck, dark-brown legs, and a white rump. This second-largest member of the deer family weighs 250–450 kilograms (550–1,000 pounds) and stands 1.5 meters (five feet) at the shoulder. Beginning each spring, stags grow an impressive set of antlers, covered in what is known as velvet. The velvet contains nutrients that stimulate antler growth. By fall, the antlers have reached their full size and the velvet is shed. Rutting season takes place between August and October; listen for the shrill bugles of the stags serenading the females. During the rut, randy males will challenge anything with their antlers and can be dangerous. The stags shed their antlers each spring, but don’t relax too much because, also in spring, females protecting their young can be equally dangerous. Large herds of elk live in and around the towns of Banff  and Jasper , often nonchalantly wandering along streets and feeding on tasty plants in residential gardens, and always safe from predators.
The giant of the deer family is the moose, an awkward-looking mammal that appears to have been designed by a cartoonist. It has the largest antlers of any animal in the world, stands up to 1.8 meters (six feet) at the shoulder, and weighs up to 500 kilograms (1,100 pounds). Its body is dark brown, and it has a prominent nose, long spindly legs, small eyes, big ears, and an odd flap of skin called a bell dangling beneath its chin. Apart from all that, it’s good-looking. Each spring the bull begins to grow palm-shaped antlers that by August will be fully grown. Moose are solitary animals preferring marshy areas and weedy lakes, but they are known to wander to higher elevations searching out open spaces in summer. They forage in and around ponds on willows, aspen, birch, grasses, and all aquatic vegetation. They are not particularly common in the Canadian Rockies, numbering around 350. Although they may appear docile, moose will attack humans if they feel threatened.
Small populations of caribou inhabit the backcountry of Banff and Jasper National Parks . They are occasionally spotted along the Icefields Parkway  south of Jasper . Native people named the animal caribou (hoof scraper) for the way in which they feed in winter, scraping away snow with their hooves. Caribou are smaller than elk and have a dark brown coat with creamy patches on the neck and rump. Both sexes grow antlers, but those of the females are shorter and have fewer points. On average males weigh 180 kilograms (400 pounds), females 115 kilograms (250 pounds). Like the elk, they breed in fall, with the males gathering a harem.