Deer (Cervidae) is a family of antlered, hoofed ruminants of the order Artiodactyla containing about 40 species worldwide (5 in Canada: white-tailed and mule deer, caribou, moose, wapiti). Deer are relatively large-brained and adaptable, but thrive only in fertile areas.

Antlers

Antlers are found on males of all Canadian species, on female barren ground caribou and a few female woodland caribou. They consist of bone, grow rapidly (4 months in moose) and are shed annually. Velvet (hairy skin, well supplied with nerves and blood vessels) covers and nourishes the growing antlers. When antlers are fully grown the velvet dies and is rubbed off, as males prepare for mating season. Antlers are used as display organs to intimidate rivals and lure females. They are rarely used against predators, however they are used as weapons and shields against rival males. Antler size, symmetry and complexity vary with age, health and diet. The largest antlers evolved in species adapted to quick, long-distance running, such as caribou, wapiti or the extinct Irish elk. Larger antlers in a species indicate larger newborns at birth and richer milk, adaptations that allow rapid growth of the young to survivable size and speed. The smallest antlers are found in territory-defending tropical deer.

Evolution

Deer began their evolutionary radiation as small-bodied, antlerless, tropical herbivores. For 30 million years they evolved slowly. As they invaded open parkland habitats and harsher climates their body and antler size increased, as did antler complexity, coat coloration and ornamentation. This evolution resulted in grotesque giants in subarctic, subalpine and glacial environments, for example, the extinct Irish elk (Old World), and the moose (New World). Weights of both could exceed 600 kg. The Alaskan bull moose may carry antlers exceeding 30 kg and 2 m in spread; those of the Irish elk exceeded 38 kg and 3 m.

Distribution and Habitat

The 2 most common deer in Canada, white-tailed and mule deer, are closely related species of the genus Odocoileus. Both occur in many subspecies including dwarf island forms. Fossils of white-tailed deer (O. virginianus) predate the last ice age. The mule deer (O. hemionus) originated more recently. Its most primitive subspecies, the black-tailed deer (O. h. columbianus), lives along the Pacific coastline from Alaska to California. A Eurasian species, fallow deer (Cervus dama), has been successfully introduced to James Island, BC.

Mule deer, characteristic of the mountains and foothills of western North America, sometimes occur as far east as Manitoba. White-tailed deer occur across southern Canada and as far north as Yukon and the Northwest Territories. If protected, both species thrive around human settlements. White-tails, being very secretive, may thrive with little protection especially in severely disturbed landscapes. While both species are wide-ranging, they do not compete well for space when confronted with Old World deer, for example the wapiti.

Survival Strategies

Both the mule and white-tailed deer are adapted to feed on soft vegetation; however, they have different antipredator strategies. Mule deer leap over obstacles in the path of pursuing predators; white-tails combine hiding with rapid getaway over unobstructed ground. Both can live in groups on open terrain and be solitary in dense forests. Females may become territorial when raising young. Black-tailed deer may cluster into group territories.

Reproduction and Development

At northern latitudes, mating occurs in late November and early December; fawns are born in June. Males guard one female at a time and do not advertise their whereabouts to rivals. Both mule and white-tail deer have long sparring ceremonies, but few fights occur.

Relationship with Humans

Many species of deer can be domesticated and the velveted antlers are used for pharmaceutical purposes. Deer have been widely introduced as game and park animals. They generally respond well to adequate habitat and protection from excessive hunting. Moose have spread widely in Eurasia and North America; in America, white-tailed and mule deer have dispersed widely and live secretly in cities where green belts or large parks provide food and cover.

In Canada, the caribou is economically and culturally significant to Aboriginal peoples, while moose and white-tailed deer provide meat for many families. White-tails are one of the most important big game animals in North America today.