The bighorn sheep ( Ovis canadensis ) is a North American native sheep species called the great horn. This horn can weigh up to 14 kg (30 pounds), while the sheep itself weighs up to 140 kg (300 pounds). Recent genetic testing shows three distinct subspecies of Ovis canadensis , one of which is endangered: O. c. sierrae . Sheep originally crossed into North America via Bering's land bridge from Siberia; populations in North America culminate in millions, and bighorn sheep entering Native American mythology. By 1900, the population had fallen to several thousand, due to the disease introduced through European cattle and babbling.
Video Bighorn sheep
Taksonomi dan genetika
Ovis canadensis is one of three mountain sheep species in North America and Siberia; the other two species are O. dalli , which includes the sheep of Dall and the sheep of the Rock, and Siberian snow sheep, O. nivicola . Wild sheep crossing Bering's Berberian bridge to Alaska during the Pleistocene (about 750,000 years ago) and then spread through western North America as far south as Baja California and the northwestern plains of Mexico. The divergence of their nearest Asian ancestor (sheep snow) occurred about 600,000 years ago. In North America, wild sheep deviate into two extant species - sheep Dall, which occupies Alaska and northwest Canada, and bighorn sheep, which range from southern Canada to Mexico. However, the status of these species is questionable given that hybridization has taken place among them in recent evolutionary history.
Subspecies
Former
In 1940, Ian McTaggart-Cowan divided the species into seven subspecies:
- Badlands bighorn or Audubon bighorn sheep, O. c. audubony , takes place in North Dakota, South Dakota, Montana, Wyoming, and Nebraska. This subspecies has been extinct since 1925.
- California bighorn sheep, O. c. californiana , found from southern British Columbia to California and east to North Dakota. The definition of this subspecies has been updated (see below).
- Nelson's bighorn sheep, O. c. nelsoni , the most common desert bighorn sheep, ranging from California to Arizona.
- Mexican bighorn sheep, O. c. mexicana , ranging from Arizona and southern New Mexico to Sonora and Chihuahua.
- bighorn sheep Peninsular O. c. cremnobates , takes place on the Peninsular Peninsula of California and Baja California
- Rocky Mountain bighorn sheep, O. c. canadensis , found from British Columbia to Arizona.
- Sheep bighorn Weems, O. c. weemsi , found in southern Baja California.
Current
Beginning in 1993, Ramey and colleagues, using DNA tests, have shown this division into seven subspecies that are mostly illusory. Most scientists today recognize three subspecies of bighorn. This taxonomy is supported by the most extensive genetic studies (microsatellite and mitochondrial DNA) to date (2016) which finds a high difference between Rocky Mountain and Sierra Nevada bighorn sheep, and that these two subspecies are separate from bighorn deserts before or during Illinoian. glaciation (about 315-94 thousand years ago). Thus, three subspecies of O. canadensis :
- Rocky bighorn sheep ( O. c. canadensis ) - occupies the US and Canadian Rockies, and the United States Northwestern.
- Sierra Nevada bighorn sheep (formerly O. c. sierrae ) - formerly California bighorn sheep, a genetically distinct subspecies that only occurs in Sierra Nevada in California. However, historical observer records show that bighorn sheep may have explored as far west as the California Coastal Ranges adjacent to the Sierra Nevada via Transversal Ranges. Notes about the "wild sheep" around the San Antonio Mission near Jolon, California, and the mountains around San Francisco Bay around 1769.
- Desert bighorn sheep ( O. c. nelsoni ) - occurs throughout the desert areas of the Southwestern United States and northwestern Mexico. The genetic studies of 2016 show a simpler difference from this desert bighorn sheep to three lineages consistent with Cowan's early work: Nelson ( O. c. Nelsoni ), Mexico ( O. c. Mexicana ), and Peninsular ( O. c. Cremnobates ). These three lineages occupy desert biomes that vary significantly in climates, suggesting exposure to various selection regimens.
In addition, two populations are currently considered threatened by the United States government:
- Sierra Nevada bighorn sheep ( O. c. sierrae ),
- A perinsular bighorn sheep, a different population segment of desert bighorn sheep ( O. c. nelsoni )
Maps Bighorn sheep
Description
The Bighorn Sheep is named for the large and curved horns borne by the ram (male). Ewes (women) also have horns, but they are shorter with less curvature. Starting from light brown to gray or dark, brown brown, with white buttocks and a layer on the backs of all four legs. Men typically weigh 58-143 kg (128-315 Â £), are 90-105 cm high (35-41 inches) across the shoulders, and 1.6 to 1.85 m (63-73 inches) long from the nose to the tail. Women are usually 34-91 kg (75-201 pounds), height 75-90 cm (30-35 inches) long, and length 1.28-1.58 m (50-62 inches). Male bighorn sheep have large horn cores, enlarged cornual and enlarged sinuses, and internal bone marrow. This adaptation serves to protect the brain by absorbing the impact of clashes. Bighorn sheep have a preorbital gland at the anterior angle of each eye, the inguinal glands in the groin, and the pedal glands on each leg. The secretion of this gland can support the behavior of dominance.
Bighorns of the Rocky Mountains are relatively large, with men sometimes over 230 kg (500 pounds) and women over 90 kg (Â £ 200). On the other hand, the Sierra Nevada male bighorn weighs only 90 kg (200 pounds) and females up to 60 kg (140 pounds). The male horn can weigh up to 14 kg (30 pounds), as much as the remaining bone in the male body.
Natural history
Ecology
The Rocky Mountains and the Sierra Nevada bighorn sheep occupy the cold mountain regions of Canada and the United States. In contrast, the subspecies of desert bighorn sheep originated from hot desert ecosystems in the Southwest of the United States and Mexico. Bighorn sheep generally inhabit alpine grasslands, grassy mountain slopes, and hilly terrain near rocky and rocky cliffs. Because bighorn sheep can not move even in snow, they prefer drier slopes, where annual snowfall is less than about 150 cm (60 inches) per year. The bighorn winter range is usually located at a lower altitude than its summer range.
Bighorn sheep are particularly susceptible to certain diseases carried by domestic sheep, such as scabies and pneumonia; supplemental deaths occur as a result of accidents involving falling or falling rocks from cliffs (the dangers of living on steep and heavy terrain). Bighorn also adapt well to climb steep terrain, where they seek protection from predators. Predation mainly occurs in sheep, which are hunted by coyotes, bobcats, lynxes, and golden eagles.
Bighorn sheep of all ages are threatened by bears, wolves, and especially puma, who may be best equipped with agility to prey on uneven and rocky habitats. They are considered good land health indicators because they are sensitive to many human-caused environmental problems. In addition to their aesthetic value, bighorn sheep are considered hunted animals desired by hunters.
Bighorn sheep graze on the grass and look for bushes, especially in autumn and winter, and look for minerals in natural salt licks. Women tend to eat and walk, perhaps to avoid predators and protect lambs, while men tend to eat and then rest and reflect, which aids in more effective digestion and greater body size improvement.
Structure and social reproduction
Bighorn sheep live in large herds, and usually do not follow single leader's ram, unlike mouflons, the ancestors of domestic sheep, who have a strict hierarchy of domination. Before the breeding season or "habit", the ram is trying to build a hierarchy of dominance to determine access to the mothership to mate. During the preratal period, most typical horn clashes occur between rams, although this behavior may occur to some extent throughout the year. Bighorn sheep show agonistic behavior: two competitors walk away from each other and then turn to face each other before jumping and crashing into the head. Rams Horns often show damage due to repeated clashes. Women show a stable, nonlinear hierarchy that correlates with age. Women can struggle for high social status when they are integrated into the hierarchy at the age of one to two years.
Rocky Mountain bighorn rams employ at least three different courting strategies. The most common and successful is a maintenance strategy, in which a sheep follows and defends a female parent. Tend to take on considerable strength and dominance, so women are more willing to care for men, feeling they are most suitable. Another tactic is flowing, that is, when a ram fights for a preserved parent. Ewes usually avoids the man who follows him, so his strategy is ineffective. Rams also use blocking strategies. They prevented a mother from accessing tense areas even before he got into estrus.
Baby Bighorn has six months' gestation. In temperate climates, the peak of the habit occurs in November with one, or rarely two, lambs born in May. Most births occur within the first two weeks of childbirth. Pregnant mothers of the Rocky Mountains migrate to the mountains in spring, presumably to deliver in safer areas of predation, but away from areas of good quality forage. Lambs born at the beginning of the season are more likely to survive than the lambs born later. Late born sheep may not have access to adequate milk, because their mothers breastfeed when the quality of food is lower. The newborn lamb weighs 3.6-4.5 kg (8 to 10 pounds) and can run within hours. The lambs are then weaned when they reach the age of four to six months. The lifespan of rams is usually 9-12 years old, and 10-14 years for female mothers.
Infectious diseases
Many bighorn sheep populations in the United States have regular epidemics of infectious pneumonia, possibly caused by the introduction of pathogenic bacteria (specifically, Mycoplasma ovipneumoniae), and several strains of Mannheimia haemolytica () are carried without symptoms in domestic sheep. Once introduced, pathogens can be transmitted rapidly through bighorn populations, resulting in deaths of all ages that sometimes kill up to 90% of the population. In the years after the introduction of pathogens, bighorn populations often experience several years of pneumonia outbreaks of sheep. This epidemic can severely limit recruitment and may play a strong role in slowing population growth.
Relationships with humans
Two hundred years ago, bighorn sheep were widespread throughout the western United States, Canada, and northern Mexico. Some estimates put their population at more than 2 million. Around 1900, hunting, competition from livestock, and disease have reduced the population to several thousand. Reintroduction programs, nature parks, and reduced hunting, along with the decline of pet sheep towards the end of World War II, allowed the bighorn sheep to return. In 2009, the California Department of Fish and Game issued 21 permits to hunt bighorn sheep, and 19 permits for the 2010-11 hunting season.
Scouting
In 1936, Arizona Boy Scouts set up a statewide campaign to save bighorn sheep. The scouts were first attracted to the sheep through the efforts of Major Frederick Russell Burnham, a known environmentalist called the "Boy Scout". Burnham observes that less than 150 sheep still live in the Arizona mountains. He called George F. Miller, then searched for executives from the Scout board headquartered in Phoenix, with plans to save the sheep. Burnham says it like this, "I want you to save this great animal, not only because it is endangered, but more importantly, someday it may provide domestic sheep with the burden of saving them from disasters in the hands of an unknown virus."
Several other prominent Arizonans joined the movement, and the "save the bighorn" poster contest started in schools across the state. Burnham rewarded and appeared in store windows in Arizona. The bighorn emblem that won the contest was made into a neck cover for 10,000 Scouts, and talks and dramatizations were given in the school assemblies and on the radio. The National Wildlife Federation, the Izaak Walton League, and the National Audubon Society also joined in this effort.
This effort led to the formation of two ranges of bighorn games in Arizona: Kofa National Wildlife Reserve and Cabeza Prieta National Wildlife Reserve. On January 18, 1939, more than 6,000 square kilometers (1,500,000 hectares) of land was set aside and a sidewalk camp of civilian conservation corps was set up to develop a high mountain hole for the sheep. Desert bighorn sheep is now the official mascot for the Boy Scouts of Arizona.
In culture
The Bighorn Sheep is one of the most admired animals of the Apsaalooka (Crow), and what today is called the Bighorn Mountains is the center of the land of the Apsaalooka tribe. In the book Bighorn Canyon National Recreation Area, Old Coyote storytellers describe the legends associated with bighorn sheep. One possessed by an evil spirit attempted to kill his heir by pushing the young man over the cliff, but the victim was saved by being trapped in the trees. Saved by a bighorn sheep, the man takes the name of their leader, Big Metal. Other sheep give him strength, wisdom, sharp eyes, definite agility, sharp ears, great strength, and a strong heart. Big Metal returns to its people with the message that the Apsaalooka people will survive only as long as the winding river out of the mountains is known as the Bighorn River.
Bighorn sheep are hunted for their meat and horns, used in ceremonies, as food, and as hunting trophies. They also serve as a source of ecotourism, as tourists come to see bighorn sheep in their natural habitat.
Rocky Mountain bighorn sheep are provincial mammals of Alberta and Colorado state animals and are thus incorporated into the emblem for the Colorado Parks and Wildlife Division.
Bighorn sheep were formerly known by scientific identification of "argali" or "argalia" because of the assumption that they are the same animal as the Asiatic argument ( Ovis ammon ). Lewis and Clark recorded many sightings of O. canadensis in their exploratory journal - sometimes using name argalia. In addition, they noted the use of bighorn sheep by Shoshone in making bows. William Clark's Track Map produced after an expedition in 1814 shows the Yellowstone tributary called Argalia Creek and a tributary of the Missouri River called the Argalia River, both in what is now Montana. None of these tributaries defend these names, however. The Bighorn River, another tributary of Yellowstone, and its streams, the Little Bighorn River are both indicated on the map of Clark and retain their names, the last of which is the name of the Bighorn Little Battle.
References
External links
- US. Fish & amp; Profile of Wildlife Services Species
- Photos & amp; Information on Wild Rocky Mountain Bighorn Sheep in Nevada.
- Animal Diversity Site
- The NatureServe website
- BIGHORN-SHEEP.com
- Texas Bighorn WebCam
- BIGHORN.org
- Rocky Mountain bighorn research
- Yellowstone Resource Guide - Bighorn Sheep
- Bighorn Desert Facts The California Sheep Department of Fish and Game
- Smithsonian Institution - North American mammal: Ovis canadensis
Source of the article : Wikipedia
0 Comments