California mule deer

Last updated

California mule deer
Odocoileus hemionus 08482.JPG
A young buck in Yosemite National Park
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Family: Cervidae
Subfamily: Capreolinae
Genus: Odocoileus
Species:
Subspecies:
O. h. californicus
Trinomial name
Odocoileus hemionus californicus
(Caton, 1876)
A mature buck in Yosemite National Park Mule deer in Yosemite Valley.jpg
A mature buck in Yosemite National Park

The California mule deer (Odocoileus hemionus californicus) is a subspecies of mule deer whose range covers much of the state of California. [1]

Contents

Anatomy

A typical mature male mule deer stands at around 40 inches in height at the shoulder and measures approximately 57 inches in total length, weighing in around 150 pounds in females and 200 pounds in males. The name "California Mule Deer" comes from their large, mule-like ears which, along with their black-tipped tail, make them easily distinguishable from other deer species. With a lifespan that can reach up to 22 years, these deer are built for endurance and adaptability, showcasing an impressive ability to navigate the diverse terrains of California, from coastal prairies to the Sierra Nevada mountains. [2]

The coat color of the California mule deer undergoes seasonal changes, allowing it to adapt to different environmental conditions. In the warmer months, their coat tends to be a lighter, reddish-brown shade, which helps them blend into the dry, sunlit landscapes. Conversely, during the colder months, the coat becomes a darker, more muted brown, offering better camouflage in the denser, shadowed terrains and against the backdrop of leafless trees or snow. These seasonal changes in coat color are essential for evading predators and for overall survival. These color changes are a process called molting, driven by a complex interplay of hormonal changes, photoperiod (length of daylight), and temperature. In most deer species, the timing of coat changes is regulated by melatonin, a hormone whose production is influenced by the photoperiod. As the days lengthen in spring and shorten in fall, the pineal gland in the brain alters its melatonin production, signaling the body to initiate the molting process. In warmer months, a lighter, thinner coat that have shorter and more thinly spaced hairs allows deer to reflect the increased solar radiation and provides less thermal insulation, allowing the deer to dissipate heat more efficiently. This lighter, thinner coat is known as the "summer pelage," and it's often a reddish-brown color that blends in with the drier landscapes. Conversely, as the days shorten and temperatures drop, signaling the approach of winter, the deer molts into its "winter pelage." This coat is characterized by longer, denser, and darker hairs that have a hollow structure, trapping air and providing better thermal insulation against the cold. The darker brown coloration also aids in camouflage against the backdrop of leafless forests and snowy landscapes. [3]

One of the principal means of distinguishing the closely related black-tailed deer and white-tailed deer is the growth habit of the buck's antlers. In the case of the Black Tail and California mule deer, the antlers fork in an upward growth, whereas the other species' antlers grow in a forward direction. These antlers consist of two main beams that then each fork into two tines. Further forking is dependent upon age, genetics, and nutrition. They will shed these antlers around mid-February and regrow them throughout the Spring.

Distribution

This subspecies, O. h. californicus, is widespread throughout northern and central California in the California coastal prairie, as well as inner coastal ranges and interior mountains, especially the Sierra Nevada. This deer is much less frequently found on the floor of the interior valleys, and then mostly frequently in riparian zones. [4] Additionally, mule deer are migratory mammals. In northern areas including Inyo and Mono counties, their summer ranges are typically located at higher elevations and are characterized by a higher plant density for foraging and fawning areas. They will migrate to lower elevations with more limited food during the winter as the higher elevations become covered with snow. In more southern areas of California including the San Bernardino mountains this migratory shift consists of seasonal elevations migrations rather than a complete shift in ranges. [5]

Habitat

The California Mule deer's habitat generally consists of hilly terrain in oak woodlands. [6] They are abundant throughout Sequoia, King's Canyon, and Yosemite national parks as well as their surrounding areas. [7]

Diet and behavior

California Mule deer are herbivorous and often browse for food within a 1-2 mile radius of a water source (including rivers and lakes) which creates a feeding area that is often located in or around shaded grassy areas upon which they will make their beds.

They will participate in a behavior where they create beds to sleep on. These beds are roughly 2 meters in diameter and often appear as flatted grassy areas. However frequently used and re-used beds may appear significantly more level and decomposed compared to their surrounding environment. [6] This behavior is often observed among bucks during the later fall season as temperatures drop. They will choose a sunny spot, remove any rocks or branches, and take a nap. These beds are often located on grasses or dry leaves under a tree or a rock, or on flattened areas of snow if there is nothing else available. [7]

Mule deer are often opportunistic and will consume a large variety of vegetation mainly consisting of whatever is available and easily digestible including stalks, flowers, fruits, seeds of grasses, forbs, buds, seeds (particularly acorns), stems, leaves, the bark of trees, shrubs, fungi, lichens, algae, mosses, and ferns. Because of their opportunistic nature, they will adjust their diet in accordance to what is available given various factors including snow and fire. In summer, California mule deer mainly browse on leaves of small trees, shrubs, and herbaceous plants, but also consume many types of berries (including blackberry, huckleberry, salal, and thimbleberry). In winter, they may expand their forage to conifers (particularly twigs of Douglas fir), aspen, willow, dogwood, juniper, and sage. Year-round, they feed on acorns; grasses are a secondary food source. Where humans have encroached on historic deer habitat by suburban development or orchards, California mule deer diversify their diet with garden plant material, tree fruit, and occasionally, pet food. [6] [8]

Fawns and does tend to browse together in familial groupings, while bucks tend to travel singly or with other bucks. California mule deer browse most actively near dawn and dusk, but also forage at night in open agricultural areas or when experiencing hunting pressure. [6]

Mule deer will often form family groups made up of 2 or more generations of females and their fawns. Grown bucks leave these groups and will occasionally form groups with other adult bucks but are more often observed living solitarily. Females will spend their summers isolated in fawning areas after their young have sufficiently grown, where they will remain until the breeding season begins again in the fall. [8]

A doe and her fawns in Auburn, California Doe and fawns July 2006.jpg
A doe and her fawns in Auburn, California

Breeding

Mule deer have been classified as occasionally polygamous and occasionally polygynous. The average lifespan of the California Mule Deer is a robust twenty-two years, making it one of the longer-lived deer species.The males have sometimes been observed wandering extensively, seeking out females, and occasionally does will seek out a dominant buck who will tend to them until breeding. In either system, larger bucks with large antlers tend to be the most dominant individuals in a community. Rutting season occurs in autumn starting as early as September and lasting occasionally until March. During this time, the does will come into estrus for a period lasting only several days. Males exhibit aggressive behavior in competing for mates. Does begin estrus again if they do not become pregnant in a process that will be repeated up to 5 times with intervals of 22–29 days between estrous periods. The gestation period for these deer is about 200 days, culminating in the birth of fawns during the spring season. [9]

Reproductively, mothers usually give birth to one to two fawns per season. Notably, first-time mothers or those in their 2nd year of birthing tend to have singleton births, contributing to an average litter size of approximately 1.5. [10]

After birth in the spring, the young fawns are highly dependent on their mothers, staying close to them throughout the summer months. They gradually become more independent as they are weaned in the autumn, usually at the age of about six months. The familial structure during this period is typically a mother-and-fawn unit, while mature bucks generally keep to themselves or form small bachelor groups. Since young fawns are more susceptible to predators like mountain lions, bobcats, and coyotes, does care for the fawns by teaching them how to forage and avoid dangers, key survival skills that they will carry into their adulthood. [11]

The buck's antlers fall off in the winter, and commence growing once more in spring in anticipation of next autumn's rut. [9]

Predation

Bobcats, mountain lions, coyotes, and American black bears are all common predators of California Mule Deer. The largest predator of the California Mule deer is the Mountain Lion. Occasionally, these predators will hunt large healthy deer; however, these predators most often prey on weak, sick, or young deer or scavenge remains of dead deer. [6]

Disease and Parasites

The California mule deer often falls victim to the woodtick, which is extremely common throughout its habitat. Additionally lungworms and the nasal botfly will enter and parasitize the deer's lungs and nasal passageways. Parasitic eye worms of the genus Thelisa or Thelazia have also been found parasitizing the deer. [7]

A buck during the rut in rural Auburn Buck Fall 2005.jpg
A buck during the rut in rural Auburn

Human interactions

Since prehistoric times, the Native American indigenous peoples of California are known to have hunted California mule deer. Thus, since about 12,000 BCE, Gage suggests that human populations have served as a control to the numbers of California mule deer. [12]

In the modern era, since European colonists and Euro-Americans settled in California, hunting pressure intensified as the human population expanded and hunting became an activity not just associated with food supply. In addition, human population growth (through urban development) in California has consumed large amounts of natural habitat of the California mule deer starting in the late 19th century and continuing through the present.

Related Research Articles

<span class="mw-page-title-main">Deer</span> Family of mammals

A deer or true deer is a hoofed ruminant ungulate of the family Cervidae. It is divided into subfamilies Cervinae and Capreolinae. Male deer of almost all species, as well as female reindeer, grow and shed new antlers each year. These antlers are bony extensions of the skull and are often used for combat between males.

<span class="mw-page-title-main">European fallow deer</span> Species of hooved mammal

The European fallow deer, also known as the common fallow deer or simply fallow deer, is a species of ruminant mammal belonging to the family Cervidae. It is historically native to Turkey and possibly the Italian Peninsula, Balkan Peninsula, and the island of Rhodes near Anatolia. Prehistorically native to and introduced into a larger portion of Europe, it has also been introduced to other regions in the world. It is one of two living species of fallow deer (Dama) alongside the Persian fallow deer.

<span class="mw-page-title-main">Sika deer</span> Species of deer native to much of East Asia

The sika deer, also known as the Northernspotted deer or the Japanese deer, is a species of deer native to much of East Asia and introduced to other parts of the world. Previously found from northern Vietnam in the south to the Russian Far East in the north, it is an uncommon species that has been extirpated in most areas of its native range, except in Japan, where it is overabundant and present in very large numbers.

<span class="mw-page-title-main">White-tailed deer</span> Species of hooved mammal

The white-tailed deer, also known commonly as the whitetail and the Virginia deer, is a medium-sized species of deer native to North America, Central America, and South America as far south as Peru and Bolivia, where it predominately inhabits high mountain terrains of the Andes. It has also been introduced to New Zealand, all the Greater Antilles in the Caribbean, and some countries in Europe, such as the Czech Republic, Finland, France, Germany, Romania and Serbia. In the Americas, it is the most widely distributed wild ungulate.

<span class="mw-page-title-main">Mule deer</span> Deer indigenous to western North America

The mule deer 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.

<span class="mw-page-title-main">Black-tailed deer</span> Subspecies of 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. They have sometimes been treated as a species, but virtually all recent authorities maintain they are subspecies.

<span class="mw-page-title-main">Sitka deer</span> Subspecies of deer

The Sitka deer or Sitka black-tailed deer is a subspecies of mule deer, similar to the Columbian black-tailed subspecies. Their name originates from Sitka, Alaska, and it is not to be confused with the similarly named sika deer. Weighing in on average between 48 and 90 kg, Sitka deer are characteristically smaller than other subspecies of mule deer. Reddish-brown in the summer, their coats darken to a gray-brown in mid- to late August. They are also good swimmers, and can occasionally be seen crossing deep channels between islands. Their average lifespan is about 10 years, but a few are known to have attained an age of 15.

<span class="mw-page-title-main">Gemsbok</span> Species of mammal

The gemsbok, or South African oryx, is a large antelope in the genus Oryx. It is endemic to the dry and barren regions of Botswana, Namibia, South Africa and Zimbabwe, mainly inhabiting the Kalahari and Namib Deserts, areas in which it is supremely adapted for survival. Previously, some sources classified the related East African oryx, or beisa oryx, as a subspecies.

<span class="mw-page-title-main">Pampas deer</span> Species of mammals belonging to the deer, muntjac, roe deer, reindeer, and moose family of ruminants

The Pampas deer is a species of deer that live in the grasslands of South America at low elevations. They are known as veado-campeiro in Portuguese and as venado or gama in Spanish. It is the only species in the genus Ozotoceros.

<span class="mw-page-title-main">Columbian white-tailed deer</span> Subspecies of deer

The Columbian white-tailed deer is one of the several subspecies of white-tailed deer in North America. It is a member of the Cervidae (deer) family, which includes mule deer, elk, moose, caribou, and the black-tailed deer that live nearby.

<span class="mw-page-title-main">Elk</span> Large antlered species of Cervid from North America and East Asia

The elk, or wapiti, is the second largest species within the deer family, Cervidae, and one of the largest terrestrial mammals in its native range of North America and Central and East Asia. The word "elk" originally referred to the European variety of the moose, Alces alces, but was transferred to Cervus canadensis by North American colonists. The name "wapiti" derives from a Shawnee and Cree word meaning "white rump" for the distinctive light fur in the rear region, just like the Bighorn Sheep.

<span class="mw-page-title-main">Deer hunting</span> Practice/activity of hunting deer

Deer hunting is hunting deer for meat and sport, an activity which dates back tens of thousands of years. Venison, the name for deer meat, is a nutritious and natural food source of animal protein that can be obtained through deer hunting. There are many different types of deer around the world that are hunted for their meat. For sport, often hunters try to kill deer with the largest and most antlers to score them using inches. There are two different categories of antlers. They are typical and nontypical. They measure tine length, beam length, and beam mass by each tine. They will add all these measurements up to get a score. This score is the score without deductions. Deductions occur when the opposite tine is not the same length as it is opposite. That score is the deducted score.

<span class="mw-page-title-main">American mountain deer</span> Extinct species of deer

Odocoileus lucasi, known commonly as the American mountain deer, is an extinct species of North American deer.

The Cedros Island mule deer is a subspecies of mule deer found only on Cedros Island off the coast of Baja California. Only about 50 individuals remain, with no captive population. Its behavior is similar to that of other subspecies of mule deer. The subspecies is threatened by feral dogs and poaching.

<span class="mw-page-title-main">Mammals of Glacier National Park (U.S.)</span>

There are at least 14 large mammal and 50 small mammal species known to occur in Glacier National Park.

<span class="mw-page-title-main">Alberta Mountain forests</span> Temperate coniferous forests ecoregion of Alberta and British Columbia, Canada

The Alberta Mountain forests are a temperate coniferous forests ecoregion of Western Canada, as defined by the World Wildlife Fund (WWF) categorization system.

<span class="mw-page-title-main">Mammals of Olympic National Park</span>

There are at least 9 large terrestrial mammals, 50 small mammals, and 14 marine mammal species known to occur in Olympic National Park.

<span class="mw-page-title-main">Deer cutaneous fibroma</span> Disease of deer

Cutaneous fibromas are common neoplasms occurring in wild and domestic deer of many species and are caused by host-specific viral infections. The fibromas occur most frequently in animals under 2 years of age, with cases in older deer reported occasionally or rarely.

References

  1. U.S. Forest Service distribution Map — Odocoileus hemionus (Mule Deer) — including subspecies californicus . accessed 3.39.2013.
  2. "NPS.gov Homepage (U.S. National Park Service)". www.nps.gov. Retrieved 2023-11-01.
  3. Halliday, Karen J.; Whitelam, Garry C. (2003-04-01). "Changes in Photoperiod or Temperature Alter the Functional Relationships between Phytochromes and Reveal Roles for phyD and phyE". Plant Physiology. 131 (4): 1913–1920. doi: 10.1104/pp.102.018135 . hdl: 20.500.11820/8a16dbb3-ef9e-4062-bfd3-5fde25f5c5b9 . ISSN   1532-2548.
  4. Clark, Howard (2004). "Occurrence of California Mule Deer in the Southern San Joaquin Valley, California" (PDF). Transactions of the Western Section of the Wildlife Society. 40: 127–128.
  5. "Mule Deer (Odocoileus hemionus)". wildlife.ca.gov. Retrieved 2023-10-10.
  6. 1 2 3 4 5 "California Mule Deer - OVLC". OVLC - Protecting your views, trails, water and wildlife. 2014-07-10. Retrieved 2023-10-25.
  7. 1 2 3 "Wildlife Portfolio of the Western National Parks (California Mule Deer)". www.nps.gov. Retrieved 2023-10-25.
  8. 1 2 "Odocoileus hemionus". www.fs.usda.gov. Retrieved 2023-10-25.
  9. 1 2 Monteith, Kevin L.; Bleich, Vernon C.; Stephenson, Thomas R.; Pierce, Becky M.; Conner, Mary M.; Kie, John G.; Bowyer, R. Terry (April 2014). "Life-history characteristics of mule deer: Effects of nutrition in a variable environment". Wildlife Monographs. 186 (1): 1–62. doi:10.1002/wmon.1011. ISSN   0084-0173.
  10. Gibb, Heather M. Anatomical refitting using metric comparison on white tailed deer (odocoileus virginianus) and mule deer (odocoileus hemionus) (Thesis). University of Missouri Libraries.
  11. Misuraca, Michael. "Odocoileus hemionus (mule deer)". Animal Diversity Web. Retrieved 2023-11-01.
  12. Gage, Timothy (1979). "The competitive interactions of man and deer in prehistoric California". Human Ecology . 7 (3): 253–268. doi:10.1007/BF00889494. S2CID   89106860.