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New World Deer (Capriolinae)

 
Animal Classification: New World deer
 

(Capriolinae)

Class: Mammalia

Order: Artiodactyla

Family: Cervidae

Subfamily: Capriolinae

Thumbnail description
New World deer have preserved the distal rudiments of the lateral metacarpal bones; the middle parts of the lateral metacarpae are reduced; and posterior portion of the nasal cavity is divided into two chambers by the vomer, which feature is retained in South American deer, but is lacking in moose and roe deer

Size
Vary in size from very small (pudu) to the largest among Cervidae (moose)

Number of genera, species
9 genera; 27 species

Habitat
Woodlands and shrublands, often forest edges; many populations of reindeer inhabit tundra or arctic desert yearlong, others migrate to openness of subarctic tundra for summer

Conservation status
Endangered: 1 species; Vulnerable: 2 species; Lower Risk/Near Threatened: 3 species; Data Deficient: 7 species

Distribution
North America, South America, Europe, and northern Asia

Evolution and systematics

Recent paleontological research in the high Arctic suggest that as late as mid-Pliocene times the Arctic portions of North America and Asia were covered by temperate forests. Together with the zoogeography and fossil record of New World deer species, this suggests that their origin lay in these northern land masses in late Tertiary times. From here they dispersed southward as climates cooled into periodic continental glaciations. The fossil record of New World deer is limited by the facts that huge continental glaciers destroyed Tertiary fossil deposits over enormous areas, while in unglaciated regions where rich plant fossil deposits are found, the acidic conditions favoring these dissolve bones. We have thus no idea what early New World deer looked like. When they first appear in areas south of the continental glaciations in North America or Eurasia, they are already well differentiated and close to modern genera. After they enter South America with the onset of major glaciations some 2 million years ago (mya), they evolved rapidly into a large array of diverse species, only some of which survived to the present. Here they evolved dwarfs, such as pudu (Pudu pudu, P. mephistophiles) and brocket deer (Mazama spp.); mountain climbing, short-legged specialists such as the huemul (Hippocamelus antisensis, H. bisculus); sophisticated swamp dwellers such as the marsh deer (Blastocerus dichotomus); gregarious plains dwellers such as pampas deer (Ozotocerus bezoarticus); as well as massively antlered, large-bodied steppe deer that are now extinct (Morenelaphus). In the north they evolved giants such as moose (Alces); herd forming reindeer or caribou (Rangifer tarandus); a large-bodied extinct form Torontoceros; forest and swamp dwellers such as the ancient white-tailed deer (Odocoileus virginianus), the oldest deer species in the world; rainforest and mountain dwellers such as black-tailed and mule deer (O. hemionus); as well as a large, short-legged, cliff adapted Rocky Mountain deer, Navahoceros, which vanished at the end of the Pleistocene. Closely related to these North Americans are the roe deer (Capreolus capreolus, C. pygargus) of Eurasia, which is a cold-climate specialist and the Chinese water deer (Hydropotes inermis). A sparse fossil record suggests that there were a few more species present in late Pliocene times. Compared to Old World deer, New World deer are more differentiated from and less related to on another. They thrived in the ecological turmoil of the Pleistocene and have often taken advantage of humanmade landscape changes in the Recent. They also suffered fewer extinctions than other groups of large mammals.

A characteristic of New World deer is that they appear in the fossil record in order of adaptation to cold climates. The species most tolerant of heat, and which therefore disperses into and colonizes tropical South America, is the white-tailed deer. A species very similar, if not identical, to it shows up in southern North America at the end of the Blancan period almost 4 mya. Moose appear about 2.6 mya. Roe deer appear about 2 mya, and reindeer, the most cold-adapted genus, appears about 1 mya. This genus is the sister genus to Navahoceros, suggesting that competition segregated these originally montane lineages, with reindeer exploiting the alpine and subalpine slopes while Navahoceros sought refuge in cliffs. Similar ecological division is seen in extant Asiatic goat (Capra) and sheep (Ovis).

Moose appear in the Pliocene fossil record first in western Eurasia. They are then large, plains-dwelling, long-legged runners (Alces [Libralces] gallicus), about the size of a red deer (Cervus elaphus), with a normal deer face and extraordinary long spoon-shaped antlers. There appear to be several species. Moose are next seen in mid-Pleistocene Eurasia during the major glaciations. It has grown into a massive giant (Alces [Cervalces] latifrons). The huge antlers are more palmate and have shorter beams than the Pliocene specimen. The skull is intermediate between that of a normal deer and contemporary moose. Such moose cross into North America, where they grow into long-legged trotters with complex large tri-lobed antlers, but retain the primitive deer-like skull (Cervalces scotti). This American stag-moose is narrowly associated with huge Pleistocene pro-glacial lakes, which were apparently its escape terrain from the many large predator species found in North America. In Siberia moose continue to evolve into the modern moose. These have even larger palms and much shorter antler beams, the muzzle became adapted to feeding on underwater vegetation, while the body changed from that of a cursor (runner) to that of a trotter. After post-Pleistocene megafaunal extinction in North America, Siberian moose colonize the northern half of that continent beginning about 10,000 years ago, where they are now widely distributed. Two fairly distinct modern moose evolved, one the west Siberian-European form, and the other the east Siberian-American form. Despite great physical differences, moose share diagnostic behaviors with white-tailed deer, mule deer, and caribou. They twin readily, and moose remained in cold climates throughout.

The Odocoileinae comprise four groups of species: North American Odocoileus deer and South American deer, reindeer, moose, and roe deer. They all branched early from an ancestral stem into different evolutionary radiations, but retain common features in body plan, behavior, and ecology. The Odocoileus and South American deer comprise one tribe, according to G. G. Simpson. These deer may be found from the Arctic Circle in Canada south to the glaciers of southern Chile, but the majority of species live in warm climates. Moose, reindeer, and roe deer are each placed into separate tribes. These deer live in the cold northern environments, including the high arctic, and have never colonized southern latitudes.

All Odocoileinae retain distal rudiments of the lateral metacarpal bones II and V, but which still retain hoof functions. Another feature is the division of the posterior portion of the nasal cavity into two chambers by the vomer. However, this feature is missing in moose and roe deer. Males have a pendular penis. Antlers are found in all genera. The dwarf deer of South America may be secondarily dwarfed, as they are exceedingly closely related to the older and more ubiquitous white-tailed deer. This species ranges from near the Arctic Circle in Canada to 18° south of the equator in South America. The short dagger-like antlers of the dwarf deer may be related to territorial defense. Reindeer and caribou have the largest antlers relative to body size among deer, while their females also carry antlers except in some woodland populations. They also are the most cursorial and gregarious deer alive.

Physical characteristics

All Capriolinae retain distal rudiments of the lateral metacarpal bones II and V, though they are important to the functioning of lateral toes. Another feature, the posterior portion of the nasal cavity that is divided into two chambers by the vomer, is retained in South American deer, but is lacking in moose and roe deer. There are different varieties of antler structure in Odocoileinae: simple spiked (Mazama, Pudu), bifurcate (Hippocamelus), dichotomous (Blastocerus), or branched (Odocoileus, Rangifer). Moose often sport wide spade-like antlers. Normally, only males wear antlers, though reindeer females grow antlers as well.

Distribution

Six genera, including Odocoileus, Ozotocerus, Blastocerus, Hippocamelus, Mazama, and Pudu, live only in the New World. One genus, Capreolus, is known in Eurasia only. Alces and Rangifer inhabit both North America and Eurasia.

Habitat

Deer belonging to Capriolinae adapt to diverse habitats. Dwarf forms of deer with short antlers and long tails (brocket deer, Mazama) are inhabitants of tropical latitudes, while large deer with dichotomous antlers (marsh deer, Blastocerus dichotomus) inhabit tropical and subtropical marshlands. Tropical savanna is the favored habitat for pampas deer (Blastocerus campestris). Subarctic dwellers are roe deer, white-tailed deer, black-tailed deer (Odocoileus hemionus), and moose and reindeer inhabit cold temperate subarctic forests, alpine, and subarctic tundra.

Behavior

The dwarf and mountain deer of South and Central America are classical territory defenders and hiders. Capreolus males defend large territories and bond females that live within their territory. This species is a classical saltor (jumper) that relies on short runs over obstacles and then hides. Odocoileus may defend fawning territories, but otherwise related females form clans so that they move over a shared home range. Males form unstable fraternal groups but disperse and compete individually over females during the rut. These deer rely on sprinting or specialized locomotion to escape predators as well as on hiding. They may form a large selfish herd in open grasslands. Pampas deer also rely on large selfish herds to escape predators, while swamp deer use extensive wetlands for that purpose. South American deer, unlike North American species, are exceedingly sensitive to predation by feral dogs as there are no native wolf-sized canids in South America. Moose live dispersed much of the time, but bulls may form unstable fraternal groups in spring and after the rut in fall. Female moose are likely to join bulls socially only if they are neither pregnant nor have a calf at heel. Moose escape predators primarily by running over obstacles that are low relative to the moose, but high relative to the pursuing predators, who then must expend great amounts of energy to follow the fleeing moose. In deep snow moose turn and fight predators using both front and hind legs. Reindeer and caribou form highly gregarious selfish herds and excel at sustained high speed running to escape predators. In sedentary populations females disperse and give birth in hiding. In migratory populations they move northward in spring onto open terrain where they congregate into birthing herds. This overloads pursuing wolves and grizzly bears with calves. The calves are highly developed at birth and soon follow the female, who produces the richest milk among all deer, ensuring rapid growth of the calf to a survivable size. This is the most migratory species of large terrestrial mammal. Bulls advertise with antlers during the rut. Females use antlers to ward off young bulls in winter, who might otherwise parasitize the female's work of digging craters in deep snow to reach lichens. Both Rangifer and Alces are large Ice Age giants compared to other species in their family.

Feeding ecology and diet

The Capriolinae diet comprises highly nutritive forages of low-fiber content: forbs, flowers, and leaves, but rarely grass. The type of diet determines speciation of the digestive system: a large mouth enables the browsing of branches, while a long sensitive tongue helps to choose among forbs and foliage. Some species have a relatively small rumen, large salivary glands, and rapid digestion. Intestines are rather short—12 to 15 times longer than body. Consequently, interchanging periods of grazing and ruminating are short. If these deer, by necessity, feed on rough fibrous forage, there are fewer interchanging of grazing and ruminating periods during their diurnal activity (only five to six, rather than the usual eight to 12).

Reproductive biology

Capriolinae are polygynous, though the overall reproductive strategy of Capriolinae differs from that of Cervinae. They have a higher reproductive rate and mature sexually earlier; most genera produce two fawns per birth. Consequently, Capriolinae species have higher population densities, including mule deer, caribou, and moose. At the same time, the species are reproductively isolated: for instance, male hybrids between the European and Siberian roe deer as well as between white-tailed deer and mule deer are sterile. Hybridization between white-tailed and black-tailed deer is restricted. Capriolinae poorly resist diseases and parasites, and poorly adapt to new conditions.

Conservation status

Deer that inhabit Central and South America (pampas deer, Ozotoceros bezoarticus; marsh deer, Blastocerus dichotomus; huemul and pudu, Pudu spp.; brocket deer, Mazama spp.); and some subspecies from the southern part of North America have experienced severe pressure from hunters and have been on the brink of extinction. These species would greatly benefit from preservation and conservation efforts. Pampas deer, for instance, were harvested by the millions in the nineteenth century, and currently is Lower Risk/Near Threatened. The subfamily Capriolinae also includes the most numerous species on Earth, including white-tailed deer, black-tailed deer, reindeer, roe deer, and moose.

Most threatened are the Capriolinae in South America, where poor residents use subsistence hunting and do not distinguish between rare species that need to be preserved and flourishing species that need regular game management. In many South American countries, there is a fierce competition between deer and livestock for pastures. Also, a drastic decrease of habitats occurs due to drainage, farm development of grasslands, and forest cut. The Chilean huemul (Hippocamelus bisulcus) is considered Endangered. Marsh deer (Blastocerus dichotomus) and Chilean pudu (Pudu pudu) are considered Vulnerable. Less studied, Data Deficient are: Peruvian huemul (Hippocamelus antisensis), and six species (of seven known) of brocket deer (Mazama spp.).

Significance to humans

Roe deer, moose, and white-tailed deer benefit from successful, extremely productive game husbandry, though farming proved to be unsuccessful. Consequently, their future lies in game management.

Reindeer is the only deer species to become domesticated. It supports local cultures throughout northern Eurasia in this capacity. Wild migratory reindeer and caribou are also significant in northern economies. While moose can be tamed and used for riding, as beasts of burden, and for milking, their fickle feeding habits and susceptibility to livestock diseases makes them difficult to keep. They are a productive, highly appreciated meat source throughout their range. Whitetailed, black-tailed, and mule deer, after recovery from severe depletion at the end of the nineteenth century, support today a rich hunting economy in North America. Roe deer fulfill a similar role in Europe.

Species accounts

European roe deer
Siberian roe deer
White-tailed deer
Black-tailed deer
Marsh deer
Chilean huemul
Southern pudu
Red brocket
Moose
Reindeer

Resources

Books:

Baskin, Leonid, and Kjell Danell. Ecology of Ungulates. A Handbook of Species in Eastern Europe, Northern and Central Asia. Heidelberg: Springer Verlag, 2003.

Bubenik, G. A., and Anthony B. Bubenik, eds. Horns, Pronghorns, and Antlers. Evolution, Morphology, Physiology, and Social Significance. Heidelberg: Springer-Verlag, 1990.

Flerov, Konstantin K. Musk Deer and Deer. Moscow: Izdatelstvo Akademii Nauk SSSR, 1952.

Geist, Valerius. Deer of the World. Mechanicsburg, PA: Stackpole Books, 1998.

Geist, Valerius, and Fritz Walther, eds. The Behaviour of Ungulates and Its Relation to Management. Gland: International Union Conservation Nature Publications, 1974.

Hudson, Robert J., Karl R. Grew, and Leonid M. Baskin, eds. Wildlife Production Systems. Economic Utilization of Wild Ungulates. Cambridge: Cambridge University Press, 1989.

Redform, K. H., and J. F. Eisenberg. Mammals of the Neotropics: The Southern Cone. Chicago and London: The University of Chicago Press, 1992.

Serret, A. El Huemul. Fantasma de la Patagonia. Buenos Aires: Zagier and Urruty Publishers, 2000.

Vislobokova, Inessa A. Fossilized Deer of Eurasia. Moscow: Nauka, 1990.

Whitehead, G. K. The Whitehead Encyclopedia of Deer. Stillwater, MN: Voyager Press, 1993.

Periodicals:

Cowan, I. McT., and V. Geist. "Aggressive Behavior in Deer of the Genus Odocoileus." Journal of Mammalogy 42, no. 4(1961): 522.

Dusek, G. L. "Ecology of White-Tailed Deer in Upland Ponderosa Pine Habitat on Southern Montana." Prairie Naturalist 19, no. 1 (1987): 1.

Hershkovitz, P. "Neotropical Deer (Cervidae). Part 1. Pudus, Genus Pudu Gray." Fieldiana Zoology New Series 11 (1982): 1.

Pac, H. I., W. F. Kasworm, L. R. Irby, and R. J. Mackie. "Ecology of the Mule Deer, Odocoileus hemionus, along the Cast Front of the Rocky Mountains, Montana." Canadian Field-Naturalist 102, no. 2 (1988): 227.

Povilitis, A. "Characteristics and Conservation of a Fragmented Population of Huemul Hippocamelus bisulcus in Central Chile." Biological Conservation 86 (1998): 97.

Sher, Andrey V. "History and Evolution of Moose in USSR." Swedish Wildlife Research "Viltrevy" 1, no. 1 (1987): 71.

[Article by: Leonid Baskin, PhD]

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Animal Classification. Grzimek's Animal Life Encyclopedia. Copyright © 2005 by The Gale Group, Inc. All rights reserved.  Read more