Back to basics: Deer taxonomy

Robert Hudson, University of Alberta

Taxonomy can be useful as well as fun! By ordering animal by genetic relationships, we can more safely generalize aspects of their behaviour, nutrition and management. For example, it is much safer to generalize that the high tolerance of wapiti for dietary copper applies to red deer but with less certainty to fallow deer and even less to white-tailed deer. In the first of this series on Back to Basics, we review the relationships of a sampling of the world’s deer.

Some deer are not deer!

One of the most startling revelations is that some deer are not deer. The mouse deer (or chevrotain) is a small tropical animal that despite its appearance and name is not a deer and barely a ruminant. It is antlerless, tusked and has a 3-chambered rather than 4-chambered stomach. The musk deer is a tusked Asian species prized for the musk from its abdominal gland. Most authorities place this species in its own family (Moschidae) because it possesses a gall bladder.

Main branches of the family tree

Members of the deer family (Cervidae) are distinguished from other ruminants by the presence, in most recent species, of bony deciduous antlers which are generally borne only by males. However, some of the more primitive members such as the water deer of Asia do not carry antlers but have long curved upper canines. The muntjac or barking deer has both canine tusks and small antlers perched on long pedicles. In reindeer and caribou, antlers are also carried by a large proportion of females.

Figure 1. The muntjac or barking deer is a tropical deer that uses both tusks and small antlers for combat.

Modern deer arose from two distinct lines recognized on the basis of the structure of the metacarpals (bones of the lower foreleg). The plesiometacarpalia (subfamily Cervinae or Old World deer) are characterized by the retention of both distal and proximal parts of the metacarpals. Their main center of evolution was Eurasia but one member, the wapiti, entered North America in the late Pleistocene. In the telenmetacarpalia (New World deer), the metacarpals are greatly reduced; only the distal parts remain although they support generally better developed dew claws. This group comprises all the deer of the Americas (subfamily Odocoileinae) as well as the roe deer, moose and reindeer/caribou.

Plesiometacarpalia: The Old World Deer

Members of this groups belong to the families Muntiacinae and Cervinae. The Cervinae have a northern circumglobal distribution but most species are found in Eurasia and the Orient.

Several lines stayed in the tropics. The genus Axis of India has two members, the brightly spotted axis or chital (Axis axis) and the smaller hog deer (Axis porcinus). Three species belong to the subgenus Rusa (the sambars and rusa). The subgenus (Rucervus) contains the barasingha and Eld's deer.

The genus Dama contains the palmate-antlered fallow deer, a medium-sized animal with characteristically palmated antlers. Most members belong to the type genus Cervus. This complex group is often divided into several subgenera. The type subgenus (Cervus) designates the red deer, maral, Asiatic wapiti and North American wapiti. At the moment, these forms are considered to be members of a single species (Cervus elaphus) but recent genetic studies may restore the distinction between the red deer and wapiti groups. The closely-related sika deer is assigned to the subgenus Sika and the rare Thorold's deer to Przewalskium. The genetic distance between red deer and wapiti is about the same as between sika and wapiti.

Figure 2. One of the most unusual member of the Cervinae is the Pere David's deer (Elaphurus) which is known only in captivity.

Telenmetacarpalia – New World Deer

Odocoileinae

Odocoileinae (American deer) are represented by 6 genera. The diminutive Pudu inhabits temperate forests of Colombia, Equador and Chile. The spike-antlered brockets (Mazama) are distributed from Panama to northern Argentina. Branch-antlered deer include the guemals (Hippocamelus), marsh deer (Blastoceros), and pampas deer (Ozotoceros). White-tailed and black-tailed deer (Odocoileus) are abundant in North America and the white-tailed deer extends into northern South America.

Capreoleinae

The Eurasian roe deer (Capreolus) is the ecological equivalent of the white-tailed deer in Europe and Asia. Roe bucks maintain breeding territories and females have delayed implantation, the only ruminant with this unusual adaptation.

Alcinae

Moose (Alces) have a circumboreal distribution and are called ‘elk, elch, alg’ in Europe where they appear to have first evolved. Their unusual but majestic appearance reveals extreme adaptation to their boreal forest home.

Rangiferinae

Rangifer (reindeer and caribou) probably originated in Beringia and the mountains of northeastern Asia. Three ecotypes are adapted to arctic islands (Svalbard reindeer, Peary caribou), tundra (mountain reindeer, barren-ground caribou) and northern forests (forest reindeer, woodland caribou).

Figure 3. Reindeer and caribou are adapted to snowy environments and lichen diets.

Farming the world’s deer

Deer have been farmed for centuries and even millennia. Today throughout the world, over 3 million reindeer are herded and almost 5 million deer of other species are farmed. Among farmed deer, sika, red deer, fallow and wapiti are the most popular species but rusa, sambar, chital and white-tailed deer are becoming established. Roe deer and mule deer have been rather difficult to farm with current experience and understanding. Production of species such as moose, musk deer and muntjac remains experimental.

Figure 4. Cervid farming is a relatively new venture in North America.