Wednesday, 18 July 2012

Bactrian Camel

The Bactrian camel (Camelus bactrianus) is a large, even-toed ungulate native to the steppes of central Asia. It is presently restricted in the wild to remote regions of the Gobi and Taklamakan Deserts of Mongolia and Xinjiang. A small number of wild Bactrian camels still roam the Mangystau Province of southwest Kazakhstan and Nubra Valley in India, and now run wild in Australia. It is one of the two surviving species of camel. The Bactrian camel has two humps on its back, in contrast to the single-humped dromedary camel.
Bactrian camels belong to a fairly small group of animals that regularly eat snow to provide their water needs. Any animals living above the snowline are obliged to do this as snow and ice are the only forms of water during winter, and by doing so their range is greatly enlarged. The latent heat of snow and ice is enormous compared with the heat capacity of water, demanding a large sacrifice in heat energy and forcing animals to eat only small amounts at a time.
Nearly all of the 2 million camels alive today are domesticated. In October 2002, the estimated 800 remaining in the wild in northwest China and Mongolia were classified as critically endangered on the IUCN Red List of Threatened Species.
Some authorities, notably the IUCN, use the binomial name Camelus ferus for the wild Bactrian camel and reserve Camelus bactrianus for the domesticated form.


Subspecies

 


Bactrian camels in Nubra Valley, India


The wild population of Bactrian camels was first described by Nikolai Przhevalsky in the late 19th century. Their name comes from the ancient historical region of Bactria. There is some evidence that the Bactrian camel can be divided into different subspecies. In particular, it has been discovered that a population of wild Bactrian camel lives within a part of the Gashun Gobi region of the Gobi Desert. This population is distinct from domesticated herds both in genetic makeup and in behavior.
As many as three regions in the genetic makeup are distinctly different from domesticated camels, with up to a 3% difference in the base genetic code. However, with so few wild camels, it is unclear what the natural genetic diversity within a population would have been.
Another difference is the ability of these wild camels to drink saltwater slush, although it is not yet certain the camel can extract useful water from it. Domesticated camels do not attempt to drink salt water, though the reason is unknown.


Description

 

The Bactrian camel is the largest mammal in its native range and rivals the Dromedary as the largest living camel. Shoulder height is from 180 to 230 cm (5.9 to 7.5 ft), head-and-body length is 225–350 cm (7.38–11.5 ft) and the tail length is 35–55 cm (14–22 in). At the top of the humps, the average height is 213 cm (6.99 ft). Body mass can range from 300 to 1,000 kg (660 to 2,200 lb), with males often being much larger and heavier than females. Its long, wooly coat varies in colour from dark brown to sandy beige. There is a mane and beard of long hair on the neck and throat, with hairs measuring up to 25 cm (9.8 in) long. The shaggy winter coat is shed extremely rapidly, with huge sections peeling off at once, appearing as if sloppily shorn off. There are two humps on the back, which are composed of fat (not water as is sometimes thought). The face is typical of a camelid, being long and somewhat triangular, with a split upper lip. There are long eyelashes, which, along with the sealable nostrils, which help to keep out dust in the frequent sandstorms which occur in their natural range. The two broad toes on each foot have undivided soles and are able to spread widely as an adaptation to walking on sand. The feet are very tough, as befits an animal of extreme environs.


Natural habitat

 

These camels are migratory, and their habitat ranges from rocky mountain massifs to flat arid desert, stony planes and sand dunes. Conditions are extremely harsh – vegetation is sparse, water sources are limited and temperatures are extreme, ranging from as low as -40°C in winter to 40°C in summer. The camels’ distribution is linked to the availability of water, with large groups congregating near rivers after rain or at the foot of the mountains, where water can be obtained from springs in the summer months, and in the form of snow during the winter.


Life History

 

Bactrian camels are exceptionally adept at withstanding wide variations in temperature - ranging from freezing cold to blistering heat. They have a remarkable ability to go without water for months at a time, but when water is available they may drink up to 57 liters at once. When well fed, the humps are plump and erect, but as resources decline the humps shrink and lean to the side. The rolling gait of the camel is accomplished by stepping forwards with both legs on the same side, much like the giraffe. Speeds of up to 65 kmph (40 mph) have been recorded under extreme pressure but they rarely move this fast. Bactrian camels are also said to be good swimmers. The sense of sight is well developed and the sense of smell is extremely good.
Bactrian Camels are diurnal, sleeping in the open at night and foraging for food during the day. They are primarily herbivorous. They are able to eat plants that are dry, prickly, salty and/or bitter and can ingest virtually any kind of vegetation. When other nutrient sources are not available, these camels may feed on carcasses, gnawing on bones, skin, or various different kinds of flesh. In more extreme conditions, they may eat any material they find, which has included rope, sandals, and even tents. Their ability to feed on a wide range of foods allows them to live in areas with sparse vegetation. With tough mouths that can withstand sharp objects such as thorns, the digestion process begins. The first time food is swallowed it is not fully chewed. The partly masticated food (called cud) goes into the stomach and later is brought back up for further chewing.
The population density of wild Bactrian camels is calculated to be 5 animals per 100 square kilometers. Wild camels generally appear to live in groups of up to 30 individuals, though most groups contain 6 to 20 individuals. A mature male acts as the leader of the group. Typically Bactrian camels seen alone are post-disperal young individuals who have just reached sexual maturity.
The mating season occurs in the fall. Males during this time are often quite violent and may bite, spit, or attempt to sit on other male camels. The age of sexual maturity varies, but is usually reached at 3 to 5 years. Gestation lasts around 13 months, with most young being born from March through April. One or occasionally two calves are produced and the female can give birth to a new calf every other year. Young bactrian camels are precocial, being able to stand and run shortly after birth, and are fairly large at an average birth weight of 36 kg (79 lb). They are nursed for about 1.5 years. The young calf stays with its mother for three to five years, until it reaches sexual maturity, and often serves to help raise subsequent generations for those years. Wild camels sometimes breed with domesticated or feral camels as well.
The lifespan of Bactrian camels is estimated at up to 50 years, often 20 to 40 in captivity. The only regular predators of wild Bactrian camels are gray wolves, which have been seen to target weaker and weather-battered camels as they try to reach oases.


History

 


Front and side of Bactrian camel head


The Bactrian camel is thought to have been domesticated (independently of the dromedary) sometime before 2500 BCE, probably in northern Iran, Northeast Afghanistan, or southwestern Turkestan. The dromedary camel is believed to have been domesticated between 4000 BCE and 2000 BCE in Arabia. As pack animals, these ungulates are virtually unsurpassed, able to carry 170–250 kg (370–550 lb) at a rate of 47 km per day, or 4 kmph over a period of four days.
Bactrian camels have been the focus of artwork throughout history. For example, western foreigners from the Tarim Basin and elsewhere were depicted in numerous ceramic figurines of the Chinese Tang dynasty (618–907).


Evolutionary history

 

As of the 1980s, a complete range of fossils suggests the first camelids appeared in North America about 30 million years ago, had a relatively small body mass and were adapted to warm climates. By the early Pleistocene (about 2 million years ago), they had already evolved into a form similar to the current Bactrian camel, and many individuals permanently migrated to the opposite end of the Bering Strait in an abrupt fashion, probably as a response to the advancing ice age. The remaining related types of American camelids are now only in South America.


Documentaries

 

  • The Story of the Weeping Camel is a 2003 Mongolian documentary/story about a family of nomadic shepherds trying to get a white colt accepted by his mother, who rejected him after a difficult birth.
  • Planet Earth: "Deserts" shows footage of wild camels from a two-month trek in the Gobi desert. It includes a "diary" section, explaining the difficulties in obtaining the footage.


Conservation

 

The Bactrian camel was identified as one of the top ten "focal species" in 2007 by the Evolutionarily Distinct and Globally Endangered (EDGE) project, which prioritises unique and threatened species for conservation. Fewer than a thousand (approximately 600 individuals) are thought to survive in the wild and the population is decreasing. The immediate threats faced by the species are all human related. Firstly, habitat loss has been high to development for mining and industrial complexes. Due to increasing human populations, wild camels are forced to share food and water sources with introduced domestic stock and are thus sometimes shot by farmers. Included in this stock is domesticated Bactrians, who freely mate with wild individuals. This has led to a concern of a loss of genetically distinct wild Bactrian camel.
Facilitated by the Wild Camel Protection Foundation (WCPF), two wildlife preserves were founded by the governments of Mongolia of China to protect the Gobi desert, the ‘Great Gobi Reserve A’ in Mongolia in 1982, and the Arjin Shan Lop Nur Nature Reserve in China in 2000. A small captive breeding program has also been started, with the ultimate goal of reintroduction.