White-tailed Deer

White-tailed Deer, Odocoileus virginianus

White-tailed Deer, Odocoileus virginianus. Photograph taken within Stone Mountain Park, Roaring Gap, North Carolina, July 2019. Photograph and identification courtesy of Faith Hubsch, Fort Lauderdale, Florida.

The White-tailed Deer, Odocoileus virginianus, is a member of the Cervidae Family of caribou, deer, moose, and elk. The Cervidae Family consists of approximately fifty-one members placed in three subfamilies and nineteen genera. There are two species in the Odocoileus genus. There are thirty-eight subspecies of White-tailed Deer. They are known in Mexico as Venado Cola Blanca.

While White-tailed Deer remain active throughout the day and night, they are most active at dusk and dawn. They are semi-gregarious and their social structure is organized around mixed “family” groups consisting of a maternal doe, her young of the year, and female offspring from previous years. In some cases, not all individuals in these groups are close relatives. Family groups range in size from two to twelve individuals. Males less than one year old form loose-knit “bachelor” groups ranging from two to five individuals. Sexes are typically segregated throughout the year, except for during rut. Temporary mixed-sex groups occasionally form when food is scarce, in open areas, when feeding in large amounts, or during the summer when family groups are split in the fawning period.

White-tailed deer exhibit a tending-bond mating system where bucks pursue, defend, and court individual does. Unlike elk who guard harems, male deer fight each other individually. During rut, bucks compete for dominance and breeding rights by locking antlers and fighting until one buck submits. The exact timing of their breeding season is linked to the photoperiod. In northern regions breeding may begin in November, whereas the breeding season in southern regions may be as late as January or February. Gestation lasts between 187 to 213 days. Like the breeding season, fawning periods vary regionally. Fawning periods in the north are short and occur during the summer, while fawning periods are more variable and last longer in the south. As parturition nears, pregnant does isolate themselves in fawning areas and drive away young females and fawns of the previous year. Does with fawns may remain in these areas for eight to ten weeks before rejoining their family groups. Fawns grow rapidly, doubling their weight in about two weeks and tripling their weight within one month. At birth males tend to be larger than females. Males fawns weigh between 2.0 kg (4 lbs 6 oz) and 6.6 kg (14 lbs 10 oz), while female fawns weigh between 1.6 kg (3 lbs 8 oz) and 3.9 kg (8 lbs 10 oz). Fawns have a reddish-brown coat with white dorsal spots that disappear around three to four months of age. Most White-tailed Deer attain sexual maturity and can breed as yearlings. Adult females usually give birth to twins. If they reproduce, fawns and yearlings typically produce a single offspring. Although it is rare, some females can have as many as five fawns in a litter. Yearling males join adult male groups or form temporary associations with other yearling males. While they can live up to twenty years in the wild, most individuals live to about six years of age. Females tend to live about two years longer than males.

White-tailed Deer are classified as browsers because they primarily consume browse and forbs. However, they also display opportunistic feeding behavior by consuming a wide variety of plant species and plant parts including tree bark, flowers, fruits, cacti, succulents, and ferns. In turn, they are preyed upon by mountain lions, bobcats, coyotes, gray wolves, American black bears, and humans. White-tailed Deer are extremely agile and escape danger by running and bounding at speeds of up to thirty miles per hour through dense vegetation and forest. As they flee, they wave their tails characteristically side-to-side. Additionally, they are good swimmers and often enter large streams and lakes to escape predators, avoid insects, or visit islands.

White-tailed Deer are native to North America, Central America, and South America. In North America they range from southern Yukon and Northwest Territories, across the southern provinces of Canada, and southward throughout most of the United States. They are rare or absent in Alaska, California, Nevada, and Utah. They are found in all of Canada except Nunavut, Newfoundland, and Labrador. In South America, they occur in Peru, Ecuador, Bolivia, Colombia, northern Brazil, Venezuela, and the Guianas. White-tailed Deer inhabit a wide range of habitats including subtropical, semi-arid, rainforest, deciduous forest, and savanna environments. Ecological limitations in northern or montane habitats are related to depth, quality, and duration of snow. In more southern latitudes and lower elevations, they are limited by the amount and temporal distribution of precipitation.

The White-tailed Deer may be confused with the Mule Deer, Odocoileus hemionus, due to their similar appearances and overlapping ranges. These species can be distinguished visually and geographically. Mule Deer can be easily identified by their large ears that are approximately three-fourths the length of their head. They are slightly larger than the White-tailed Deer and have a distinctive black forehead that contrasts with their light gray face. While Mule Deer are also found in North America, their range is not as large. Their easternmost distribution only reaches the Western Plains States in the United States, and they occur as far south as central Mexico.

From a conservation perspective, the White-tailed Deer is currently considered to be of Least Concern due to their adaptability to a wide range of human dominated and natural habitats, occurrence in large populations, occurrence in several protected areas, and currently stable populations. In some portions of their range, populations have been increasing for almost a century. In other areas, populations are small and in decline. Threats include feral dogs, overhunting, and habitat loss. Poaching is another cause of local population extinction.