Mule deer

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Eumetazoa

Mule Deer[1]
Mule deer male and female in Modoc County, California
Conservation status
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Family: Cervidae
Genus: Odocoileus
Species: O. hemionus
Binomial name
Odocoileus hemionus
(Rafinesque, 1817)
Subspecies

10, but some disputed (see text)

The mule deer (Odocoileus hemionus) is a deer indigenous to western North America, named for its large mule-like ears. There are believed to be several subspecies, including the black-tailed deer.[2][3][4][5][6][7] Unlike its cousin, the white-tailed deer, mule deer are generally more associated with the land west of the Missouri River, and more specifically with the Rocky Mountain region of North America. Mule deer have also been introduced to Kauai (Hawaii) and Argentina.[3] The most noticeable differences between whitetails and mule deer are the size of their ears, the color of their tails, and the configuration of their antlers. In many cases, body size is also a key difference. The mule deer's tail is black-tipped, whereas the whitetail's is not. Mule deer antlers are bifurcated; in other words, they "fork" as they grow, rather than branching from a single main beam, as is the case with whitetails. Each spring, after mating season, a buck's antlers start to regrow almost immediately after the old antlers are shed. Shedding typically takes place in mid February, with variations occurring by locale. Although capable of running, mule deer often prefer to stot, with all four feet coming down together.

The mule deer is the larger of the two Odocoileus species, with a height averaging about 40–42 inches (100–110 cm) at the shoulders and a nose-to-tail length of about 80 inches (200 cm). Adult bucks normally weigh 150–300 pounds (68–140 kg), although trophy specimens may weigh around 450 pounds (200 kg); does weigh around 125–175 pounds (57–79 kg).[8] Unlike the whitetail, the mule deer does not show marked size variation across its range.

Contents

[edit] Seasonal behaviors

In addition to movements related to available shelter and food, the breeding cycle is important in understanding deer behavior. The "rut" or mating season usually begins in the fall as does go into estrus for a period of a few days and males become more aggressive, competing for mates. Does may mate with more than one buck and go back into estrus within a month if they do not settle. The gestation period is about 190–200 days, with fawns born in the spring, staying with their mothers during the summer and being weaned in the fall after about 60–75 days. A buck's antlers fall off during the winter, to grow again in preparation for the next season's rut. For more information see the main article on deer.

Mule Deer at Rocky Mountain Arsenal National Wildlife Refuge outside of Denver Colorado.

There are several non-human predators of mule deer. Gray Wolves and mountain lions are the main predator of adult deer. Bobcats, Coyotes, American Black Bears and Grizzly Bears less commonly prey on adult deer, though commonly attack fawns.[9]

[edit] Foraging

Mule deer utilize a wide variety of plant foods, and their preferences vary widely geographically as well as seasonally, but they are primarily browsers on woody vegetation and eat relatively little grass. They readily adapt to agricultural products and landscape plantings.[10][11] In summer, Mule Deer chiefly forage on not only herbaceous plants, but also various berries (including blackberry, blueberry, salal, and thimbleberry). They also use grasses more than in winter.[11] Mule deer are known to forage in summer on California Buckeye leaves, even though there is some evidence of that plant's toxicity.[12]

Mule Deer grazing in Zion National Park
A Mule Deer buck grazing near Leavenworth, Washington
A Mule Deer doe grazing in Alberta, Canada

In winter, these deer forage on conifers (especially Douglas-fir, cedar, Taxus yews, juniper), and twigs of deciduous trees and shrubs (esp. aspen, willow, dogwood, serviceberry, and sage). In season, they eat acorns and apples. Over much of the species range, snow and ice cover many food sources and the food that is accessible grows slower. The deer's metabolism slows and individuals become less active to survive in an environment with less food. A large fraction of the deaths in a mule deer population occur in the winter, especially during the first year of life.[citation needed]

During the winter, mule deer often move down from mountains, where the snow is deeper and covers most of the food, into valleys where there is less snow. Sometimes, in response to perceived distress, concerned people create feeding programs. Such supplemental feeding efforts may be harmful if not properly implemented.[13]

Mule deer rarely travel far from water or forage, and often bed down within easy walking distance of both. Young mule deer generally forage together in family groups; older bucks tend to travel alone or with other bucks. Most actively foraging around dawn and dusk, they usually bed down in protected areas mid-day, but will also forage at night in more open agricultural areas, during full moons, or when pressured by hunters. Repeated beds will often be scratched level, about the size of a washtub. Temporary beds will seem little more than flattened grassy grounds.[citation needed]

[edit] Survival

The major enemies of this deer are humans driving automobiles or hunting them, and their top predators are large carnivores such as mountain lions, black bears and coyotes. Mule deer are not well equipped for fighting back, so they rely on speed and being alert to avoid predation and human-inflicted harm.[citation needed]

[edit] Taxonomy

The mule deer can be divided into two main groups: The mule deer (sensu stricto) and the black-tailed deer. The first group includes all subspecies, except O. h. columbianus and O. h. sitkensis, which are in the black-tailed deer group.[3] The two main groups have been treated as separate species, but they hybridize, and virtually all recent authorities treat the mule deer and black-tailed deer as conspecific.[2][3][4][5][7][14] It appears the mule deer evolved from the black-tailed deer.[7] Despite this, the mtDNA of the white-tailed deer and mule deer is similar, but differs from that of the black-tailed deer.[7] This may be the result of introgression, although hybrids between the mule deer and white-tailed deer are rare in the wild (apparently more common locally in west Texas), and the hybrid survival rate is low even in captivity.[6][7] Many claims of observations of wild hybrids are not legitimate, as identification based on external features is complicated.[6]

[edit] Subspecies

Distribution map of seven mule deer subspecies:
  Sitka black-tailed deer (O. h. sitkensis)
  Black-tailed deer (O. h. columbianus)
  California mule deer (O. h. californicus)
  Southern mule deer (O. h. fuliginatus)
  Peninsula mule deer (O. h. peninsulae)
  Desert mule deer (O. h. eremicus)
  Rocky Mountain mule deer (O. h. hemionus)

Some authorities have recognized O. h. crooki as a senior synonym of O. h. eremicus, but the type specimen of the former is a hybrid between the mule deer and white-tailed deer, and the name O. h. crooki is therefore invalid.[3][15] Additionally, the validity of O. h. inyoensis has been questioned, and the two insular O. h. cerrosensis and O. h. sheldoni may be synonyms of O. h. eremicus or O. h. peninsulae.[14]

The 10 valid subspecies based on the 3rd edition of Mammal Species of the World are:[3]

[edit] References

  1. ^ "Odocoileus hemionus". Integrated Taxonomic Information System. http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=180698. Retrieved 23 March 2006. 
  2. ^ a b c Sanchez Rojas, G. & Gallina Tessaro, S. (2008). Odocoileus hemionus. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 8 April 2009. Database entry includes a brief justification of why this species is of least concern.
  3. ^ a b c d e f Wilson, Don E.; Reeder, DeeAnn M., eds. (2005). Mammal Species of the World (3rd ed.). Baltimore: Johns Hopkins University Press, 2 vols. (2142 pp.). ISBN 978-0-8018-8221-0. OCLC 62265494. http://www.bucknell.edu/msw3/browse.asp?id=14200267. 
  4. ^ a b Novak, R. M. (1999). Walker's Mammals of the World. 6th edition. ISBN 0-8018-5789-9
  5. ^ a b Reid, F. A. (2006). Mammals of North America. 4th edition. ISBN 978-0-395-93596-5
  6. ^ a b c Heffelfinger, J. (Ver. 2, March 2011). Tails with a dark side: The truth about whitetail–mule deer hybrids.
  7. ^ a b c d e Geist, V. (1998). Deer of the world: their evolution, behaviour, and ecology. ISBN 978-0811704960
  8. ^ Petersen, David (Nov./Dec., 1985). "North American Deer: Mule, Whitetail and Coastal Blacktail Deer". Mother Earth News. Ogden Publications, Inc. Retrieved 4 January 2012.
  9. ^ Odocoileus hemionus, Animal Diversity
  10. ^ Armstrong, David M. Species Profile: Deer. At Colorado Division of Wildlife. [1] Retrieved 12/16/11.
  11. ^ a b Martin, A.C., H.S. Zim, and A.L. Nelson. 1951. American Wildlife and Plants: A Guide to Wildlife Food Habits. Dover Books edition, 1961. New York.
  12. ^ C.Michael Hogan (2008) Aesculus californica, Globaltwitcher.com, ed. N. Stromberg
  13. ^ http://www.dfg.ca.gov/wildlife/hunting/deer/docs/NAMuleDeerConsPlanFinal.pdf
  14. ^ a b Feldhamer, G. A., B. C. Thompson, and J. A. Chapman, editors (2003). Wild mammals of North America: biology, management, and conservation. 2nd edition. ISBN 978-0801874161
  15. ^ Heffelfinger, J. (2000). Status of the name Odocoileus hemionus crooki (Mammalia: Cervidae). Proceedings of the Biological Society of Washington 113: 319-333

[edit] External links

Wikimedia Commons has media related to: Odocoileus hemionus
Wikispecies has information related to: Odocoileus hemionus
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