Facts About Deer
Credit: Wild Art/Shutterstock.com

The deer family is quite large, with 47 species, and includes caribou, elk, moose and wapiti. They are cloven-hoofed ungulates identified by their antlers, long bodies and necks, slender legs and small tails.   

Deer range from very large to very small. The smallest deer is the Southern pudu, according to the ARKive project. It weighs only around 20 lbs. (9 kilograms) and gets to be only around 14 inches (36 centimeters) tall when fully grown. [Related: Oh, You Deer: Newborn Mini Fawn Is Seriously Cute]

The world's largest deer, extinct as of 11,000 years ago, was the Irish deer. It reached a massive 7 feet (2.1 meters) from hooves to shoulder, and its antlers spanned up to 12 feet (3.65 m), according to the University of California Museum of Paleontology. The largest living deer is the moose. It can grow up to 6.5 feet (2 m) from hoof to shoulder and weigh around 1,800 lbs. (820 kg).

All deer species have antlers, except for the Chinese water deer. Except for caribou, only males have antlers. Antlers grow from boney supporting structures called pedicels, according to the University of Michigan's Animal Diversity Web (ADW). They are covered in "velvet," which is rich in nerves and blood vessels. When the antlers are fully grown, the velvet dies and the deer will rub it off against a tree or other vegetation.

Some deer, such as muntjacs, have short spikes as antlers. Other species, like moose, have large branched structures. Males use their antlers in competition during mating season and shed them soon after. 

Deer are found all over the world, with the exception of Australia and Antarctica. While other continents have a wide array of deer, Africa only has one, the Barbary red deer, according to ADW. The Southern pudu is native to Chile and Argentina. A deer common to North and South America is the white-tailed deer.

Deer are found in many different ecosystems. They live in wetlands, deciduous forests, grasslands, rain forests, arid scrublands and mountains. Sometimes, when human civilizations get too close to home, deer will even make themselves comfortable in urban settings.

Deer are very social and travel in groups called herds. The herd is often led by a dominant male, though with some species the herds are segregated by sex. Sometimes the females will have their own herd and the males will have a separate herd. In other cases, a female herd is watched over by a herd of males. Some caribou herds can have as many as 100,000 members, according to ADW. 

Most deer are active throughout the day, though their most active times are during sunrise and dusk. They spend their days foraging for food.

Deer are herbivores; they only eat vegetation. For the most part, a deer's diet consists of grass, small shrubs and leaves, though they will forage in trash bins and in gardens if they cannot find the vegetation they need elsewhere. 

Though not common, some deer are monogamous, such as the European Roe deer. When a deer breeds depends on where it lives. Deer in temperate areas breed during late autumn or early winter. Deer that live in lower latitudes breed from late spring into early summer. Deer that live in tropical climates mate whenever they want, which could be several times per year. 

Deer carry their young for a gestation period of 180 to 240 days. Usually, the larger the deer, the longer the mother carries it in her womb. Deer usually only have one to three young at a time and these young are called fawns. Some of the large deer babies are also called calves.

Deer range in color from dark to very light brown, according to ADW, and fawns are born with white spots to help camouflage them from predators. Fawns are weaned at two to five months of age. Deer are unable to fully mature unless they reach a certain size, though how big they need to be varies depending on species. Overall, most deer live 11 to 12 years, though many die long before then due to predators or environmental dangers such as collisions with cars.

The taxonomy of deer, according to the Integrated Taxonomic Information System (ITIS), is:

Kingdom: Animalia
Subkingdom: Bilateria
Infrakingdom: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclass: Tetrapoda
Class: Mammalia
Subclass: Theria
Infraclass: Eutheria
Order: Artiodactyla
Family: Cervidae 

Subfamilies & genera:

  • Capreolinae: Alces, Blastocerus, Capreolus, Hippocamelus, Mazama, Odocoileus, Ozotoceros, Pudu, Rangifer
  • Cervinae: Axis, Cervus, Dama, Elaphodus, Elaphurus, Muntiacus, Przewalskium, Rucervus, Rusa
  • Hydropotinae: Hydropotes
A mule deer missing an antler. Deer loose their antlers each year and re-grow new ones from stem cells in the base of the antler.
A mule deer missing an antler. Deer loose their antlers each year and re-grow new ones from stem cells in the base of the antler.
Credit: Wikimedia Commons user Hustvedt

Species (47), including:

  • Alces alces (moose)
  • Odocoileus virginianus (white-tailed deer)
  • Rangifer tarandus (reindeer / caribou)
  • Pudu puda (Southern pudu)
  • Cervus elaphus (elk, wapiti, red deer)
  • Cervus nippon (Sika deer)
  • Muntiacus muntjak (Indian muntjac)
  • Hydropotes inermis (Chinese water deer)

According to the International Union for Conservation of Nature (IUCN), many deer species are currently endangered. The IUCN's Red List of Threatened Species includes the Calamian deer, Bawean deer, hog deer, Persian Fallow deer and the Chinanteco deer. The Père David's deer is extinct in the wild and now can only be found in captive populations, according to the IUCN.

No magic here. Reindeer are actually caribou, according to the San Diego Zoo

The Chinese water deer is the only species that doesn't shed its antlers, because it doesn't have any. Instead, it has very long canine teeth that it uses to attract mates.

Deer have one main stomach and three "false stomachs." Like cows, they chew their cud to fully digest their food.

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