The mule deer (''Odocoileus hemionus'') is a

deer Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the reindeer ...

indigenous to western

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

; it is named for its ears, which are large like those of the

mule The mule is a domestic equine hybrid between a donkey and a horse. It is the offspring of a male donkey (a jack) and a female horse (a mare). The horse and the donkey are different species, with different numbers of chromosomes; of the two pos ...

. Two

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

of mule deer are grouped into the

black-tailed deer Two forms of black-tailed deer or blacktail deer that occupy coastal woodlands in the Pacific Northwest of North America are subspecies of the mule deer (''Odocoileus hemionus''). They have sometimes been treated as a species, but virtually all r ...

. Unlike the related

white-tailed deer The white-tailed deer (''Odocoileus virginianus''), also known as the whitetail or Virginia deer, is a medium-sized deer native to North America, Central America, and South America as far south as Peru and Bolivia. It has also been introduced t ...

(''Odocoileus virginianus''), which is found throughout most of North America east of the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...

and in the valleys of the Rocky Mountains from

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyom ...

and

Wyoming Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...

northward, mule deer are only found on the western

Great Plains The Great Plains (french: Grandes Plaines), sometimes simply "the Plains", is a broad expanse of flatland in North America. It is located west of the Mississippi River and east of the Rocky Mountains, much of it covered in prairie, steppe, an ...

, in the Rocky Mountains, in the

southwest United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, Ne ...

, and on the west coast of North America. Mule deer have also been introduced to

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

and

Kauai, Hawaii Kauai, () anglicized as Kauai ( ), is geologically the second-oldest of the main Hawaiian Islands (after Niʻihau). With an area of 562.3 square miles (1,456.4 km2), it is the fourth-largest of these islands and the 21st largest island ...

Taxonomy

Mule deer can be divided into two main groups: the mule deer (''

sensu stricto ''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular co ...

'') and the

. The first group includes all subspecies, except ''O. h. columbianus'' and '' O. h. sitkensis'', which are in the black-tailed deer group. The two main groups have been treated as separate species, but they

hybridize Hybridization (or hybridisation) may refer to: *Hybridization (biology), the process of combining different varieties of organisms to create a hybrid *Orbital hybridization, in chemistry, the mixing of atomic orbitals into new hybrid orbitals *Nu ...

, and virtually all recent authorities treat the mule deer and black-tailed deer as

conspecific Biological specificity is the tendency of a characteristic such as a behavior or a biochemical variation to occur in a particular species. Biochemist Linus Pauling stated that "Biological specificity is the set of characteristics of living organ ...

. Mule deer apparently

evolved Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation t ...

from the black-tailed deer. Despite this, the

mtDNA Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial DNA ...

of the white-tailed deer and mule deer is similar, but differs from that of the black-tailed deer. This may be the result of

introgression Introgression, also known as introgressive hybridization, in genetics is the transfer of genetic material from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species. Intr ...

, although hybrids between the mule deer and white-tailed deer are rare in the wild (apparently more common locally in

West Texas West Texas is a loosely defined region in the U.S. state of Texas, generally encompassing the arid and semiarid lands west of a line drawn between the cities of Wichita Falls, Abilene, and Del Rio. No consensus exists on the boundary betwee ...

), and the hybrid

survival rate Survival rate is a part of survival analysis. It is the proportion of people in a study or treatment group still alive at a given period of time after diagnosis. It is a method of describing prognosis in certain disease conditions, and can be use ...

is low even in captivity. Many claims of observations of wild hybrids are not legitimate, as identification based on external features is complicated.

Subspecies

Some authorities have recognized ''O. h. crooki'' as a

senior synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linnae ...

of ''O. h. eremicus'', but the

type specimen In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...

of the former is a

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two dif ...

between the mule deer and white-tailed deer, so the name ''O. h. crooki'' is invalid. Additionally, the validity of ''O. h. inyoensis'' has been questioned, and the two insular ''O. h. cerrosensis'' and ''O. h. sheldoni'' may be

synonyms A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

of ''O. h. eremicus'' or ''O. h. peninsulae''. The 10 valid subspecies, based on the third edition of ''

Mammal Species of the World ''Mammal Species of the World: A Taxonomic and Geographic Reference'' is a standard reference work in mammalogy giving descriptions and bibliographic data for the known species of mammals. It is now in its third edition, published in late 2005, ...

'', are: * Mule deer (''sensu stricto'') group: **'' O. h. californicus'' – California mule deer **'' O. h. cerrosensis'' – Cedros/Cerros Island mule deer; named after

Cedros Island Cedros Island (''Isla de Cedros'', "island of cedars" in Spanish) is an island in the Pacific Ocean belonging to the state of Baja California, Mexico. The dry and rocky island had a population of 1,350 in 2005 and has an area of which includes ...

, the only place the subspecies is found **''O. h. eremicus'' – desert/burro mule deer; found in the Lower Colorado River Valley, northwestern Mexico, southeastern California, and

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

**''O. h. fuliginatus'' – southern mule deer; found in southernmost California and

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

**''O. h. hemionus'' – Rocky Mountain mule deer; found in western and central North America **''O. h. inyoensis'' – Inyo mule deer; named after

Inyo County, California Inyo County () is a county in the eastern central part of the U.S. state of California, located between the Sierra Nevada and the state of Nevada. In the 2020 census, the population was 19,016. The county seat is Independence. Inyo County is ...

and found in the

Sierra Nevada The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primarily ...

mountain range in California **''O. h. peninsulae'' – peninsular mule deer; found in

Baja California Sur Baja California Sur (; 'South Lower California'), officially the Free and Sovereign State of Baja California Sur ( es, Estado Libre y Soberano de Baja California Sur), is the least populated state and the 31st admitted state of the 32 federal ent ...

**''O. h. sheldoni'' – Tiburon Island mule deer; found on

Tiburón Island Tiburón Island is the largest island in the Gulf of California and the largest island in Mexico, with an area of . It was made a nature reserve in 1963 by President Adolfo López Mateos. Etymology is Spanish for 'shark'. Although the Seri nam ...

* Black-tailed deer group: **'' O. h. columbianus'' – Columbian black-tailed deer; found in the

Pacific Northwest The Pacific Northwest (sometimes Cascadia, or simply abbreviated as PNW) is a geographic region in western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though ...

and

Northern California Northern California (colloquially known as NorCal) is a geographic and cultural region that generally comprises the northern portion of the U.S. state of California. Spanning the state's northernmost 48 counties, its main population centers incl ...

regions **'' O. h. sitkensis'' – Sitka deer; named after

Sitka, Alaska russian: Ситка , native_name_lang = tli , settlement_type = Consolidated city-borough , image_skyline = File:Sitka 84 Elev 135.jpg , image_caption = Downtown Sitka in 1984 , image_size ...

and found in the coastal area and islands off western

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

Description

Mule Deer Sulphur Springs Valley Arizona 2014

The most noticeable differences between white-tailed and mule deer are ear size, tail color, and antler configuration. In many cases, body size is also a key difference. The mule deer's tail is black-tipped, whereas the white-tailed deer's is not. Mule deer antlers are bifurcated; they "fork" as they grow, rather than branching from a single main beam, as is the case with white-tails. Each spring, 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 are often seen

stotting Stotting (also called pronking or pronging) is a behavior of quadrupeds, particularly gazelles, in which they spring into the air, lifting all four feet off the ground simultaneously. Usually, the legs are held in a relatively stiff position. Ma ...

(also called pronking), with all four feet coming down together. The mule deer is the larger of the three ''

Odocoileus ''Odocoileus'' is a genus of medium-sized deer (family Cervidae) containing three species native to the Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South Am ...

'' species on average, with a height of at the shoulders and a nose-to-tail length ranging from . Of this, the tail may comprise . Adult bucks normally weigh , averaging around , although trophy specimens may weigh up to . Does (female deer) are smaller and typically weigh from , with an average of around . Unlike the white-tailed, the mule deer does not generally show marked size variation across its range, although environmental conditions can cause considerable weight fluctuations in any given population. An exception to this is the

Sitka deer The Sitka deer or Sitka black-tailed deer (''Odocoileus hemionus sitkensis'') is a subspecies of mule deer (''Odocoileus hemionus''), similar to the Columbian black-tailed subspecies (''O. h. colombianus''). Their name originates from Sitka, A ...

subspecies (''O. h. sitkensis''). This race is markedly smaller than other mule deer, with an average weight of and in males and females, respectively.

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 The estrous cycle (, originally ) is the set of recurring physiological changes that are induced by reproductive hormones in most mammalian therian females. Estrous cycles start after sexual maturity in females and are interrupted by anestrous p ...

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 did not become pregnant. The gestation period is about 190–200 days, with fawns born in the spring. The survival rate of the fawns during labor is about 50%. Fawns stay with their mothers during the summer and are weaned in the fall after about 60–75 days. Mule deer females usually give birth to two fawns, although if it is their first time having a fawn, they often have just one. A buck's antlers fall off during the winter, then grow again in preparation for the next season's rut. The annual cycle of antler growth is regulated by changes in the length of the day. The size of mule deer groups follows a marked seasonal pattern. Groups are smallest during fawning season (June and July in Saskatchewan and Alberta) and largest in early gestation (winter; February and March in Saskatchewan and Alberta). Besides humans, the three leading predators of mule deer are

coyote The coyote (''Canis latrans'') is a species of canis, canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecologica ...

wolves The wolf (''Canis lupus''; plural, : wolves), also known as the gray wolf or grey wolf, is a large Canis, canine native to Eurasia and North America. More than thirty subspecies of Canis lupus, subspecies of ''Canis lupus'' have been reco ...

, and

cougar The cougar (''Puma concolor'') is a large Felidae, cat native to the Americas. Its Species distribution, range spans from the Canadian Yukon to the southern Andes in South America and is the most widespread of any large wild terrestrial mamm ...

Bobcat The bobcat (''Lynx rufus''), also known as the red lynx, is a medium-sized cat native to North America. It ranges from southern Canada through most of the contiguous United States to Oaxaca in Mexico. It is listed as Least Concern on the IUC ...

Canada lynx The Canada lynx (''Lynx canadensis''), or Canadian lynx, is a medium-sized North American lynx that ranges across Alaska, Canada, and northern areas of the contiguous United States. It is characterized by its long, dense fur, triangular ears ...

wolverine The wolverine (), (''Gulo gulo''; ''Gulo'' is Latin for "gluttony, glutton"), also referred to as the glutton, carcajou, or quickhatch (from East Cree, ''kwiihkwahaacheew''), is the largest land-dwelling species of the family Mustelidae. It is ...

American black bear The American black bear (''Ursus americanus''), also called simply a black bear or sometimes a baribal, is a medium-sized bear endemic to North America. It is the continent's smallest and most widely distributed bear species. American black bear ...

s, and

grizzly bear The grizzly bear (''Ursus arctos horribilis''), also known as the North American brown bear or simply grizzly, is a population or subspecies of the brown bear inhabiting North America. In addition to the mainland grizzly (''Ursus arctos horri ...

s may prey upon adult deer, but most often only attack fawns or infirm specimens, or eat a deer after it has died naturally. Bears and smaller-sized carnivores are typically

opportunistic feeders Feeding is the process by which organisms, typically animals, obtain food. Terminology often uses either the suffixes -vore, -vory, or -vorous from Latin ''vorare'', meaning "to devour", or -phage, -phagy, or -phagous from Greek φαγ ...

, and pose little threat to a strong, healthy mule deer.

Diet and foraging behaviors

In 99 studies of mule deer diets, some 788 species of plants were eaten by mule deer, and their diets vary greatly depending on the season, geographic region, year, and elevation. The studies gave these data for Rocky Mountain mule deer diets: The diets of mule deer are very similar to those of white-tailed deer in areas where they coexist. Mule deer are intermediate feeders rather than pure

browsers Browse, browser or browsing may refer to: Programs * Web browser, a program used to access the World Wide Web *Code browser, a program for navigating source code * File browser or file manager, a program used to manage files and related objects * ...

or grazers; they predominantly browse, but also eat

forb A forb or phorb is an herbaceous flowering plant that is not a graminoid (grass, sedge, or rush). The term is used in biology and in vegetation ecology, especially in relation to grasslands and understory. Typically these are dicots without woo ...

vegetation, small amounts of grass, and where available, tree or shrub fruits such as

bean A bean is the seed of several plants in the family Fabaceae, which are used as vegetables for human or animal food. They can be cooked in many different ways, including boiling, frying, and baking, and are used in many traditional dishes th ...

s, pods,

nut Nut often refers to: * Nut (fruit), fruit composed of a hard shell and a seed, or a collective noun for dry and edible fruits or seeds * Nut (hardware), fastener used with a bolt Nut or Nuts may also refer to: Arts, entertainment, and media Co ...

s (including

acorn The acorn, or oaknut, is the nut of the oaks and their close relatives (genera ''Quercus'' and '' Lithocarpus'', in the family Fagaceae). It usually contains one seed (occasionally two seeds), enclosed in a tough, leathery shell, and borne ...

s), and

berries A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone or pit, although many pips or seeds may be present. Common examples are strawberries, raspb ...

. Mule deer readily adapt to agricultural products and landscape plantings. In the Sierra Nevada range, mule deer depend on the lichen ''

Bryoria fremontii ''Bryoria fremontii'' is a dark brown, horsehair lichen that grows hanging from trees in western North America, and northern Europe and Asia. It grows abundantly in some areas, and is an important traditional food for a few First Nations in No ...

'' as a winter food source. The most common plant species consumed by mule deer are: * Among trees and shrubs: ''

Artemisia tridentata ''Artemisia tridentata'', commonly called big sagebrush,MacKay, Pam (2013), ''Mojave Desert Wildflowers'', 2nd ed., , p. 264. Great Basin sagebrush or (locally) simply sagebrush, is an aromatic shrub from the family Asteraceae, which grows in ari ...

'' (big sagebrush), '' Cercocarpus ledifolius'' (curlleaf mountain mahogany), ''

Cercocarpus montanus ''Cercocarpus montanus'' is a North American species of shrub or small tree in the family Rosaceae native to northern Mexico and the western United States. It is known by the common names alder-leaf mountain-mahogany, alder-leaf cercocarpus, and ...

'' (true mountain mahogany), ''

Cowania mexicana ''Purshia mexicana'' is a species of perennial flowering small tree in the rose family known by the common name Mexican cliffrose. It is native to western-northern Mexico, the region of the Sierra Madre Occidental cordillera. '' Purshia stansbur ...

'' (Mexican cliffrose), ''

Populus tremuloides ''Populus tremuloides'' is a deciduous tree native to cooler areas of North America, one of several species referred to by the common name aspen. It is commonly called quaking aspen, trembling aspen, American aspen, mountain or golden aspen, tr ...

'' (quaking aspen), ''

Purshia tridentata ''Purshia tridentata'', with the common name bitterbrush, is a shrub in the genus '' Purshia'' of the family Rosaceae. It is native to mountainous areas of western North America. Common names include antelope bitterbrush, antelope bush, buc ...

'' (antelope bitterbrush), ''

Quercus gambelii ''Quercus gambelii'', with the common name Gambel oak, is a deciduous small tree or large shrub that is widespread in the foothills and lower mountains of western North America. It is also regionally called scrub oak, oak brush, and white oak. ...

'' (Gambel oak), and ''

Rhus trilobata ''Rhus trilobata'' is a shrub in the sumac genus ('' Rhus'') with the common names skunkbush sumac, sourberry, skunkbush, and three-leaf sumac. It is native to the western half of Canada and the Western United States, from the Great Plains to ...

'' (skunkbush sumac). * Among forbs: ''

Achillea millefolium ''Achillea millefolium'', commonly known as yarrow () or common yarrow, is a flowering plant in the family Asteraceae. Other common names include old man's pepper, devil's nettle, sanguinary, milfoil, soldier's woundwort, and thousand seal. The ...

'' (western yarrow), ''

Antennaria ''Antennaria'' is a genus of dioecious perennial herbs in the family Asteraceae, native to temperate regions of the Northern Hemisphere, with a few species (''A. chilensis'', ''A. linearifolia'', ''A. sleumeri'') in temperate southern South A ...

'' (pussytoes) species, ''

Artemisia frigida ''Artemisia frigida'' is a widespread species of flowering plant in the aster family, which is known as the sunflower family. It is native to Europe, Asia, and much of North America. In parts of the north-central and northeastern United States ...

'' (fringed sagebrush), ''

Artemisia ludoviciana ''Artemisia ludoviciana'' is a North American species of flowering plant in the daisy family Asteraceae, known by several common names, including silver wormwood, western mugwort, Louisiana wormwood, white sagebrush, lobed cud-weed, and gray sag ...

'' (Louisiana sagewort), ''

Aster Aster or ASTER may refer to: Biology * ''Aster'' (genus), a genus of flowering plants ** List of ''Aster'' synonyms, other genera formerly included in ''Aster'' and still called asters in English * Aster (cell biology), a cellular structure shap ...

'' species, ''

Astragalus ''Astragalus'' is a large genus of over 3,000 species of herbs and small shrubs, belonging to the legume family Fabaceae and the subfamily Faboideae. It is the largest genus of plants in terms of described species. The genus is native to tempe ...

'' (milkvetch) species, ''

Balsamorhiza sagittata ''Balsamorhiza sagittata'' is a North American species of flowering plant in the tribe Heliantheae of the family Asteraceae known by the common name Arrowleaf Balsamroot. It is widespread across western Canada and much of the western United State ...

'' (arrowleaf balsamroot), ''

Cirsium ''Cirsium'' is a genus of perennial and biennial flowering plants in the Asteraceae, one of several genera known commonly as thistles. They are more precisely known as plume thistles. These differ from other thistle genera ('' Carduus'', ''Silyb ...

'' (thistle) species, ''

Erigeron ''Erigeron'' () is a large genus of plants in the family Asteraceae. It is closely related to the genus '' Aster'' and the true daisies in the genus '' Bellis''. The genus has a cosmopolitan distribution in dry, mountainous areas and grassland, ...

'' (fleabane) species, ''

Geranium ''Geranium'' is a genus of 422 species of annual, biennial, and perennial plants that are commonly known as geraniums or cranesbills. They are found throughout the temperate regions of the world and the mountains of the tropics, but mostly in ...

'' species, ''

Lactuca serriola ''Lactuca serriola'', also called prickly lettuce, milk thistle (not to be confused with ''Silybum marianum'', also called milk thistle), compass plant, and scarole, is an annual or biennial plant in the tribe Cichorieae within the family Asterac ...

'' (prickly lettuce), ''

Lupinus ''Lupinus'', commonly known as lupin, lupine, or regionally bluebonnet etc., is a genus of plants in the legume family Fabaceae. The genus includes over 199 species, with centers of diversity in North and South America. Smaller centers occur ...

'' (lupine) species,

alfalfa Alfalfa () (''Medicago sativa''), also called lucerne, is a perennial flowering plant in the legume family Fabaceae. It is cultivated as an important forage crop in many countries around the world. It is used for grazing, hay, and silage, as w ...

, ''

Penstemon ''Penstemon'' , the beardtongues, is a large genus of roughly 250 species of flowering plants native mostly to the Nearctic, but with a few species also found in the North American portion of the Neotropics. It is the largest genus of flowering ...

'' species, ''

Phlox ''Phlox'' (; Greek φλόξ "flame"; plural "phlox" or "phloxes", Greek φλόγες ''phlóges'') is a genus of 67 species of perennial and annual plants in the family Polemoniaceae. They are found mostly in North America (one in Siberia) in di ...

'' species, ''

Polygonum ''Polygonum'' is a genus of about 130 species of flowering plant in the buckwheat and knotweed family Polygonaceae. Common names include knotweed and knotgrass (though the common names may refer more broadly to plants from Polygonaceae). In the ...

'' (knotweed/smartweed) species, ''

Potentilla ''Potentilla'' is a genus containing over 300Guillén, A., et al. (2005)Reproductive biology of the Iberian species of ''Potentilla'' L. (Rosaceae).''Anales del Jardín Botánico de Madrid'' 1(62) 9–21. species of annual, biennial and perenni ...

'' (cinquefoil) species, ''

Taraxacum officinale ''Taraxacum officinale'', the dandelion or common dandelion, is a flowering herbaceous perennial plant of the dandelion genus in the family Asteraceae (syn. Compositae). The common dandelion is well known for its yellow flower heads that turn i ...

'' (dandelion), ''

Tragopogon dubius ''Tragopogon dubius'' (yellow salsify, western salsify, western goat's-beard, wild oysterplant, yellow goat's beard, goat's beard, goatsbeard, common salsify, salsify) is a species of salsify native to southern and central Europe and western As ...

'' (western salsify),

clover Clover or trefoil are common names for plants of the genus ''Trifolium'' (from Latin ''tres'' 'three' + ''folium'' 'leaf'), consisting of about 300 species of flowering plants in the legume or pea family Fabaceae originating in Europe. The genus ...

, and ''

Vicia americana ''Vicia americana'' is a species of legume in the vetch genus known by the common names American vetch and purple vetch. It includes a subspecies known as mat vetch. Description It is a climbing perennial forb that grows from both taproot and ...

'' (American vetch). * Among grasses and grasslike species: ''

Agropyron ''Agropyron'' is a genus of Eurasian plants in the Poaceae, grass family), native to Europe and Asia but widely naturalized in North America. Species in the genus are common name, commonly referred to as wheatgrass. ; Species * ''Agropyron bada ...

'', '' Elymus'' (wheatgrasses), ''

Elytrigia ''Elytrigia'' is a genus of about 20–40 species of grasses, native to temperate regions of the Old World, in Europe, Asia, and northwest Africa. The species are sometimes included in the related genera ''Agropyron'' or '' Elymus'', while spec ...

'', ''

Pascopyrum ''Pascopyrum'' is a monotypic genus of grass containing the sole species ''Pascopyrum smithii'', which is known by the common names western wheatgrass and red-joint wheatgrass, after the red coloration of the nodes. It is native to North America. ...

'' species (

wheatgrass Wheatgrass is the freshly sprouted first leaves of the common wheat plant (''Triticum aestivum''), used as a food, drink, or dietary supplement. Wheatgrass is served freeze dried or fresh, and so it differs from wheat malt, which is convecti ...

es), '' Pseudoroegneria spicatum'' (bluebunch wheatgrass), ''

Bromus tectorum ''Bromus tectorum'', known as downy brome, drooping brome or cheatgrass, is a winter annual grass native to Europe, southwestern Asia, and northern Africa, but has become invasive in many other areas. It now is present in most of Europe, southe ...

'' (cheatgrass), ''

Carex ''Carex'' is a vast genus of more than 2,000 species of grass-like plants in the family Cyperaceae, commonly known as sedges (or seg, in older books). Other members of the family Cyperaceae are also called sedges, however those of genus ''Carex'' ...

'' (sedge) species, ''

Festuca idahoensis ''Festuca idahoensis'' is a species of grass known by the common names Idaho fescue and blue bunchgrass. It is native to western North America, where it is widespread and common. It can be found in many ecosystems, from shady forests to open plai ...

'' (Idaho fescue), '' Poa fendleriana'' ( muttongrass), ''

Poa pratensis ''Poa pratensis'', commonly known as Kentucky bluegrass (or blue grass), smooth meadow-grass, or common meadow-grass, is a perennial species of grass native to practically all of Europe, North Asia and the mountains of Algeria and Morocco. Altho ...

'' (Kentucky bluegrass), and other '' Poa'' (bluegrass) species. Mule deer have also been known to eat

ricegrass ''Oryzopsis'' is a genus of Chinese and North American plants in the grass family. Species from this genus are commonly called ricegrass.gramagrass, and

needlegrass The term needlegrass may refer to any of several genera of grasses, including: *'' Achnatherum'' *''Aristida'' (three-awns) *'' Hesperostipa'' *''Nassella'' *''Stipa'' *''Triraphis'' See also * Spear grass (disambiguation) * Wiregrass (disambigua ...

, as well as

bearberry Bearberries (indigenous kinnickinnick) are three species of dwarf shrubs in the genus ''Arctostaphylos''. Unlike the other species of ''Arctostaphylos'' (see manzanita), they are adapted to Arctic and Subarctic climates, and have a circumpolar d ...

bitter cherry ''Prunus emarginata'', the bitter cherry or Oregon cherry, is a species of ''Prunus'' native to western North America, from British Columbia south to Baja California, and east as far as western Wyoming and New Mexico. It is often found in recentl ...

black oak Black Oak may refer to: Places in the United States * Black Oak, Arkansas * Black Oak, Daviess County, Indiana * Black Oak, Lake County, Indiana, a neighborhood of Gary, Indiana * Black Oak, Missouri Other * Black Oak Arkansas Black Oak Ar ...

California buckeye ''Aesculus californica'', commonly known as the California buckeye or California horse-chestnut, is a species of buckeye native to California and southwestern Oregon. Description It is a large deciduous shrub or small tree, up to tall, with ...

ceanothus ''Ceanothus'' is a genus of about 50–60 species of Actinorhizal plant, nitrogen-fixing shrubs and small trees in the buckthorn family (Rhamnaceae). Common names for members of this genus are buckbrush, California lilac, soap bush, or just ceano ...

cedar Cedar may refer to: Trees and plants *''Cedrus'', common English name cedar, an Old-World genus of coniferous trees in the plant family Pinaceae *Cedar (plant), a list of trees and plants known as cedar Places United States * Cedar, Arizona * ...

cliffrose ''Purshia'' (bitterbrush or cliff-rose) is a small genus of 5–8 species of flowering plants in the family Rosaceae which are native to western North America. Description ''Purshia'' species form deciduous or evergreen shrubs, typically reach ...

, cottonwood,

creek dogwood ''Cornus sericea'', the red osier or red-osier dogwood, is a species of flowering plant in the family (biology), family Cornaceae, native to much of North America. It has sometimes been considered a synonym of the Asian species ''Cornus alba''. ...

, creeping barberry,

dogwood ''Cornus'' is a genus of about 30–60 species of woody plants in the family Cornaceae, commonly known as dogwoods, which can generally be distinguished by their blossoms, berries, and distinctive bark. Most are deciduous trees or shrub ...

Douglas fir The Douglas fir (''Pseudotsuga menziesii'') is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Oregon pine, and Columbian pine. There are three va ...

elderberry ''Sambucus'' is a genus of flowering plants in the family Adoxaceae. The various species are commonly called elder or elderberry. The genus was formerly placed in the honeysuckle family, Caprifoliaceae, but was reclassified as Adoxaceae due to ge ...

, ''

Fendlera ''Fendlera'' is a genus of shrubs in the Hydrangeaceae. They are most commonly known as fendlerbush. The name fendlerbush is also used for the closely related genus ''Fendlerella''. The genus was named for Augustus Fendler Augustus Fendler (Ja ...

'' species,

goldeneye ''GoldenEye'' is a 1995 spy film, the seventeenth in the ''James Bond'' series produced by Eon Productions, and the first to star Pierce Brosnan as the fictional MI6 agent James Bond. Directed by Martin Campbell, it was the first in the ser ...

, holly-leaf buckthorn,

jack pine Jack pine (''Pinus banksiana'') is an eastern North American pine. Its native range in Canada is east of the Rocky Mountains from the Mackenzie River in the Northwest Territories to Cape Breton Island in Nova Scotia, and the north-central and ...

knotweed Knotweed is a common name for plants in several genera in the family Polygonaceae. Knotweed may refer to: * ''Fallopia'' * ''Persicaria'' * ''Polygonum'' * ''Reynoutria japonica ''Reynoutria japonica'', synonyms ''Fallopia japonica'' and ''Poly ...

, ''

Kohleria ''Kohleria'' is a New World genus of the flowering plant family Gesneriaceae. The plants are generally tropical herbs or subshrubs with velvety stems and foliage and brightly colored flowers with spots or markings in contrasting colors. They are ...

'' species,

manzanita Manzanita is a common name for many species of the genus ''Arctostaphylos''. They are evergreen shrubs or small trees present in the chaparral biome of western North America, where they occur from Southern British Columbia and Washington to Or ...

mesquite Mesquite is a common name for several plants in the genus ''Prosopis'', which contains over 40 species of small leguminous trees. They are native to dry areas in the Americas. They have extremely long roots to seek water from very far under grou ...

pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accep ...

rabbitbrush Rabbitbrush is a common name for shrubs, principally of the western United States, in three related genera of the family Asteraceae: * '' Chrysothamnus'' — about seven species in the United States, including Greene's rabbitbrush * ''Ericame ...

ragweed Ragweeds are flowering plants in the genus ''Ambrosia'' in the aster family, Asteraceae. They are distributed in the tropical and subtropical regions of the Americas, especially North America,redberry,

scrub oak Scrub oak is a common name for several species of small, shrubby oaks. It may refer to: *the Chaparral plant community in California, or to one of the following species. In California *California scrub oak (''Quercus berberidifolia''), a widespr ...

serviceberry ''Amelanchier'' ( ), also known as shadbush, shadwood or shadblow, serviceberry or sarvisberry (or just sarvis), juneberry, saskatoon, sugarplum, wild-plum or chuckley pear,A Digital Flora of Newfoundland and Labrador Vascular Plants/ref> is a g ...

(including Pacific serviceberry), Sierra juniper, silktassel,

snowberry ''Symphoricarpos'', commonly known as the snowberry, waxberry, or ghostberry, is a small genus of about 15 species of deciduous shrubs in the honeysuckle family, Caprifoliaceae. With the exception of the Chinese coralberry, '' S. sinensis'', whi ...

, stonecrop,

sunflower The common sunflower (''Helianthus annuus'') is a large annual forb of the genus ''Helianthus'' grown as a crop for its edible oily seeds. Apart from cooking oil production, it is also used as livestock forage (as a meal or a silage plant), as ...

, tesota,

thimbleberry ''Rubus parviflorus'', commonly called thimbleberry, (also known as redcaps) is a species of ''Rubus'' native to northern temperate regions of North America. The plant has large hairy leaves and no thorns. It bears edible red fruit similar in a ...

, turbinella oak, velvet elder, western chokecherry, wild cherry, and wild oats. Where available, mule deer also eat a variety of wild

mushroom A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans. The standard for the name "mushroom" is t ...

s, which are most abundant in late summer and fall in the southern Rocky Mountains; mushrooms provide moisture, protein, phosphorus, and potassium. Humans sometimes engage in supplemental feeding efforts in severe winters in an attempt to avoid mule deer starvation. Wildlife agencies discourage such efforts, which cause harm to mule deer populations by spreading disease (such as

tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in ...

and

chronic wasting disease Chronic wasting disease (CWD), sometimes called zombie deer disease, is a transmissible spongiform encephalopathy (TSE) affecting deer. TSEs are a family of diseases thought to be caused by misfolded proteins called prions and include similar dis ...

) when deer congregate for feed, disrupting migratory patterns, causing

overpopulation Overpopulation or overabundance is a phenomenon in which a species' population becomes larger than the carrying capacity of its environment. This may be caused by increased birth rates, lowered mortality rates, reduced predation or large scale m ...

of local mule deer populations, and cause

habitat destruction Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

overbrowsing of shrubs and forbs. Supplemental feeding efforts might be appropriate when carefully conducted under limited circumstances, but to be successful, the feeding must begin early in the severe winter (before poor range conditions and severe weather cause malnourishment or starvation) and must be continued until range conditions can support the herd. Mule deer are variably gregarious, with a large proportion of solitary individuals (35 to 64%) and small groups (groups with ≤5 deer, 50 to 78%). Reported mean

group size Many animals, including humans, tend to live in groups, herds, flocks, bands, packs, shoals, or colonies (hereafter: groups) of conspecific individuals. The size of these groups, as expressed by the number of people/etc in a group such as eight g ...

measurements are three to five and typical group size (i.e. crowding) is about seven. File:Mule Deer foraging at Okanagan Mountain Provincial Park.webm, Mule deer foraging on a late winter morning at

Okanagan Mountain Provincial Park Okanagan Mountain Provincial Park is a provincial park within the Okanagan-Similkameen Regional District of British Columbia, Canada, focused on the mountain of the same name and located on the east side of Okanagan Lake, opposite Peachland and ...

File:Mule Deer in Zion Canyon.jpeg, Male Rocky Mountain mule deer (''O. h. hemionus'') in

Zion National Park Zion National Park is an American national park located in southwestern Utah near the town of Springdale. Located at the junction of the Colorado Plateau, Great Basin, and Mojave Desert regions, the park has a unique geography and a variety ...

File:muledeerleavenworth.jpg, Male ''O. h. hemionus'' near

Leavenworth, Washington Leavenworth is a city in Chelan County, Washington, Chelan County, Washington (state), Washington, United States. It is part of the Wenatchee, Washington, Wenatchee−East Wenatchee, Washington, East Wenatchee Wenatchee-East Wenatchee metropolit ...

File:Odocoileus hemionus 5432.JPG, Female Columbian black-tailed deer (''O. h. columbianus'') in

Olympic National Park Olympic National Park is a United States national park located in the State of Washington, on the Olympic Peninsula. The park has four regions: the Pacific coastline, alpine areas, the west-side temperate rainforest, and the forests of the drier ...

File:Female mule deer in Garden of the Gods, Colorado Springs, Colorado, USA.jpg, Female mule deer in Garden of the Gods, Colorado Springs, Colorado, USA.

Nutrition

Mule deer are

ruminants Ruminants ( suborder Ruminantia) are hoofed herbivorous grazing or browsing mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial actions. The ...

, meaning they employ a nutrient acquisition strategy of fermenting plant material before digesting it. Deer consuming high-fiber, low-starch diets require less food than those consuming high-starch, low-fiber diets. Rumination time also increases when deer consume high-fiber, low-starch diets, which allows for increased nutrient acquisition due to greater length of fermentation. Because some of the subspecies of mule deer are migratory, they encounter variable habitats and forage quality throughout the year. Forages consumed in the summer are higher in digestible components (i.e. proteins, starches, sugars, and

hemicellulose A hemicellulose (also known as polyose) is one of a number of heteropolymer, heteropolymers (matrix polysaccharides), such as arabinoxylans, present along with cellulose in almost all embryophyte, terrestrial plant cell walls.Scheller HV, Ulvskov H ...

) than those consumed in the winter. The average gross energy content of the consumed forage material is 4.5kcal/g. Due to fluctuations in forage quality and availability, mule deer fat storage varies throughout the year, with the most fat stored in October, which is depleted throughout the winter to the lowest levels of fat storage in March. Changes in hormone levels are indications of physiological adjustments to the changes in the habitat. Total body fat is a measure of the individual's energy reserves, while

thyroid hormone File:Thyroid_system.svg, upright=1.5, The thyroid system of the thyroid hormones T3 and T4 rect 376 268 820 433 Thyroid-stimulating hormone rect 411 200 849 266 Thyrotropin-releasing hormone rect 297 168 502 200 Hypothalamus rect 66 216 386 25 ...

concentrations are a metric to determine the deer's ability to use the fat reserves.

Triiodothyronine Triiodothyronine, also known as T3, is a thyroid hormone. It affects almost every physiological process in the body, including growth and development, metabolism, body temperature, and heart rate. Production of T3 and its prohormone thyroxine ( ...

(T3) hormone is directly involved with

basal metabolic rate Basal metabolic rate (BMR) is the rate of food energy, energy expenditure per unit time by endotherm, endothermic animals at rest. It is reported in energy units per unit time ranging from watt (joule/second) to ml O2/min or joule per hour per kg b ...

and thermoregulation.

Migration

Mule deer migrate from low elevation winter ranges to high elevations summer ranges. Although not all individuals in populations migrate, some will travel long distances between summer and winter ranges. Researchers discovered the longest mule deer migration in Wyoming spanning 150 miles from winter to summer range Multiple US states track mule deer migrations. Mule deer migrate in fall to avoid harsh winter conditions like deep snow that covers up food resources, and in spring follow the emergence of new growth northwards. There is evidence to suggest that mule deer migrate based on cognitive memory, meaning they use the same path year after year even if the availability of resources has changed. This contradicts the idea that animals will go to the areas with the best available resources, which makes migratory paths crucial for survival.

Risks

There are many risks that mule deer face during migration including climate change and human disturbance. Climate change impacts on seasonal growth patterns constitute a risk for migrating mule deer by invalidating historic or learned migration paths. Human activities such as natural resource extraction, highways, fencing, and urban development all have an impact on mule deer populations and migrations through habitat degradation and fragmentation. Natural gas extraction has been found to have varying negative effects on mule deer behavior and can even cause them to avoid areas they use to migrate. Highways not only cause injury and death to mule deer, but they can also serve as a barrier to migration. As traffic volumes increase, the more mule deer tend to avoid those areas and abandon their typical migration routes. It has also been found that fencing can alter deer behavior, acting as a barrier, and potentially changing mule deer migration patterns. In addition, urban development has replaced mule deer habitat with subdivisions, and human activity has increased. As a result of this, researchers have seen a decline in mule deer populations. This is especially prominent in Colorado where the population has grown by over 2.2 million since 1980.

Management

Protecting migration corridors

Protecting migrations corridors is essential to maintain healthy mule deer populations. One thing everyone can do is help slow the increase in climate change by using greener energy sources and reducing the amount of waste in our households. In addition, managers and researchers can assess the risks listed above and take the proper steps to mitigate any adverse impacts those risk have on mule deer populations. Not only will populations benefit from these efforts but so will many other wildlife species.

Highways

One way to help protect deer from getting hit on roadways is to install high fence wildlife fencing with escape routes. This helps keep deer off the road, preventing vehicle collisions and allowing animals that are trapped between the road and the fence a way to escape to safety. However, to maintain migration routes that cross busy highways, managers have also implemented natural, vegetated, overpasses and underpasses to allow animals, like mule deer, to migrate and move safely across highways.

Natural resource extraction

Approaches to mitigating the impact of drilling and mining operations include regulating the time of year when active drilling and heavy traffic to sites are taking place, and using well-informed planning to protect critical deer habitat and using barriers to mitigate the activity, noise, light at the extraction sites.

Urban development

The increase in urbanization has impacted mule deer migrations and there is evidence to show it also disrupts gene flow among mule deer populations. One clear option is to not build houses in critical mule deer habitat; however, build near mule deer habitat has resulted in some deer becoming accustom to humans and the resources, such as food and water. Rather than migrate through urban areas some deer tend to stay close to those urban developments, potentially for resources and to avoid the obstacles in urban areas. Suggested measures by property owners to protect mule deer genetic diversity and migration paths include planting deer-resistant plants, placing scare devices such as noise-makers, and desisting from feeding deer.

Disease

Wildlife officials in

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...

announced that a November–December 2021 field study had detected the first case of SARS-CoV-2 in mule deer. Several deer possessed apparent SARS-CoV-2 antibodies, however a female deer in Morgan County had an active

Delta variant The Delta variant (B.1.617.2) was a variant of SARS-CoV-2, the virus that causes COVID-19. It was first detected in India in late 2020. The Delta variant was named on 31 May 2021 and had spread to over 179 countries by 22 November 2021. The ...

infection.

White-tailed deer The white-tailed deer (''Odocoileus virginianus''), also known as the whitetail or Virginia deer, is a medium-sized deer native to North America, Central America, and South America as far south as Peru and Bolivia. It has also been introduced t ...

, which are able to hybridize with mule deer and which have shown high rates of SARS-CoV-2 infection, have migrated into Morgan County and other traditional mule deer habitats since at least the early 2000s.

References

External links

Mule Deer ''Odocoileus hemionus'' (Rafinesque 1817)
at the ''

Encyclopedia of Life The ''Encyclopedia of Life'' (''EOL'') is a free, online encyclopedia intended to document all of the 1.9 million living species known to science. It is compiled from existing trusted databases curated by experts and with the assistance of non ...

'' {{Taxonbar, from=Q338831 Odocoileus Mammals of North America

mule deer The mule deer (''Odocoileus hemionus'') is a deer indigenous to western North America; it is named for its ears, which are large like those of the mule. Two subspecies of mule deer are grouped into the black-tailed deer. Unlike the related whit ...

Articles containing video clips Taxa named by Constantine Samuel Rafinesque

Taxonomy

Subspecies

Description

Seasonal behaviors

Diet and foraging behaviors

Nutrition

Migration

Risks

Management

Protecting migration corridors

Highways

Natural resource extraction

Urban development

Disease

References

Further reading

External links