yak

Yak
A yak in Nepal
Conservation status
Vulnerable (IUCN 3.1)[1]
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Artiodactyla Family: Bovidae Genus: Bos Species: B. grunniens
Binomial name
Bos grunniens Linnaeus, 1766
Synonyms
Poephagus grunniens

The yak (Bos grunniens)(Tibetan: གཡག་; Wylie: g.yak) is a long-haired bovine found throughout the Himalayan region of south Central Asia, the Qinghai-Tibetan Plateau and as far north as Mongolia. In addition to a large domestic population, there is a small, vulnerable wild yak population. In Tibetan, the word gyag refers only to the male of the species; a female is a dri or nak. In most languages which borrowed the word, including English, yak is usually used for both sexes. The first Yaks were descended from European Ox.^{[citation needed]}

Yaks are herd animals. Wild male yaks stand about 2 to 2.2 metres (6.6 to 7.2 ft) tall at the shoulder and average 1,000 kg (2,200 lb); the females weigh about one third of this.^[2] domesticated yaks are much smaller, males weighing 350 to 580 kg (770 to 1,300 lb) and females 225 to 255 kg (500 to 560 lb).^[3] Both types have long shaggy hair to insulate them from the cold. Wild yaks can be brown or black. Domesticated ones can also be white. Both males and females have horns.

Domestic yaks mate in about September; the females may first conceive at about 3–4 years of age, calving April to June about every other or every third year, apparently depending upon food supply. This gestation period is approximately 9 months. In the absence of more data, wild animals are assumed to mirror this reproductive behavior. Calves will be weaned at one year and become independent shortly thereafter. Yaks may live to somewhat more than 20 years.

Wild yaks

Yak at a zoo in Syracuse, New York.

Wild yaks (Tibetan: འབྲོང་; Wylie: 'brong) can weigh up to 1,200 kg (2,600 lb) and have a head and body length of 3 to 3.4 m (9.8 to 11 ft). They usually form groups of between 10 and 30 animals. Their habitat is treeless uplands such as hills, mountains and plateaus between 3,200 and 5,400 m (10,000 and 18,000 ft). Yak physiology is well adapted to high altitudes, having larger lungs and heart than cattle found at lower altitudes, as well as greater capacity for transporting oxygen through their blood.^[4] Conversely, yaks do not thrive at lower altitudes.^[5] They eat grasses, lichens and other plants.^[6] They are insulated by dense, close, matted under-hair as well as their shaggy outer hair.^[7] Yaks secrete a special sticky substance in their sweat which helps keep their under-hair matted and acts as extra insulation. This secretion is used in traditional Nepalese medicine. Many wild yaks are killed for food by the Tibetans; they are now a vulnerable species.^[8] Historically, the main natural predator of the wild yak has been the Tibetan Wolf (Canis lupus chanco).

Thubten Jigme Norbu, the elder brother of Tenzin Gyatso, the 14th Dalai Lama, reports on his journey from Kumbum in Amdo to Lhasa in 1950 that:

"Before long I was to see the vast herds of drongs with my own eyes. The sight of those beautiful and powerful beasts who from time immemorial have made their home on Tibet's high and barren plateaux never ceased to fascinate me. Somehow these shy creatures manage to sustain themselves on the stunted grass roots which is all that nature provides in those parts. And what a wonderful sight it is to see a great herd of them plunging head down in a wild gallop across the steppes. The earth shakes under their heels and a vast cloud of dust marks their passage. At nights they will protect themselves from the cold by huddling up together, with the calves in the centre. They will stand like this in a snow-storm, pressed so close together that the condensation from their breath rises into the air like a column of steam. The nomad have occasionally tried to bring up young drongs as domestic animals, but they have never entirely succeeded. Somehow once they live together with human beings they seem to lose their astonishing strength and powers of endurance; and they are no use at all as pack animals, because their backs immediately get sore. Their immemorial relationship with humans has therefore remained that of game and hunter, for their flesh is very tasty."^[9]

Domesticated yaks

Woman and yak at Qinghai Lake

Domesticated yaks are kept primarily for their milk, fiber and meat, and as beasts of burden. They transport goods across mountain passes for local farmers and traders as well as for climbing and trekking expeditions. "Only one thing makes it hard to use yaks for long journeys in barren regions. They will not eat grain, which could be carried on the journey. They will starve unless they can be brought to a place where there is grass." ^[10] They also are used to draw ploughs. Yak dung is even burned as fuel. Yak milk is often processed to a cheese called chhurpi in Tibetan and Nepali languages, and byaslag in Mongolia. Butter made of Yaks' milk is an ingredient of the butter tea that Tibetans consume in large quantities,^[11] and is also used in lamps and made into butter sculptures used in religious festivities.^[12]

Often the pack animals are actually crossbreeds of the yak and Bos taurus (common domestic cattle). These are known in Tibetan as dzo or dzopkyo, and in Mongolian as khainag. Yaks grunt, and unlike cattle are not known to produce the characteristic bovine lowing sound.

Yak fiber

Each yak produces around 2.5 kg (5.5 lb) annually of a mixture of hair and fine downy fiber; high-yielding types may produce as much as 25 kg (55 lb).^[13] The fiber is combed or shed from the yak, and the hair separated from the down. The hair is used to make ropes, rugs and various other products. The down is soft and smooth and about 3 cm (1.2 in) 1.2 inches long, and it can be spun into yarn for knitting. The average fineness of down from an adult yak is 18-20 microns, while the length is around 30 to 40 mm (1.2 to 1.6 in). Yaks that live in higher altitudes have finer fiber. The most common natural color of the yak is a dark chocolate brown, but can also be found in white, tan, and grey. Unlike wool, the scales of yak fiber are in a waved mosaic pattern, resulting in a very smooth fiber that does not itch.

Yak hide is used to make shoes and bags and in the construction of coracle-like boats.

In sport

In parts of Tibet, yak racing is considered a high source of entertainment at traditional Tibetan festivals.

More recently, sports involving domesticated yaks, such as yak skiing, or yak polo, are being marketed as tourist attractions in Central Asian countries.

Gallery

Yaks in Manali, India saddled for riding	A train of pack yaks at Litang monastery in Sichuan, China	Yaks plowing fields in Tibet.	In Tibet, yaks are sometimes decorated.
Explorers riding yaks. 1870s.	Baggage Yak, 1870s	Yaks with loads. 1870s	Farmer with decorated yaks near Shigatse. 1938.

References

1. ^ Harris, R.B. & Leslie, D. (2008). Bos mutus. 2008 IUCN Red List of Threatened Species. IUCN 2008. Retrieved on 29 March 2009. Database entry includes a brief justification of why this species is of vulnerable.
2. ^ Nowak, R. 1999. Walker's Mammals of the World, 6th Edition, Volume II. Baltimore: Johns Hopkins University Press (quoted in Oliphant, M. 2003. "Bos grunniens" (On-line), Animal Diversity Web. Accessed April 04, 2009)
3. ^ Buchholtz, C. 1990. True Cattle (Genus Bos). Pp. 386-397 in S. Parker, ed. Grzimek's Encyclopedia of Mammals, Volume 5. New York: McGraw-Hill Publishing Company. (quoted in Oliphant, M. 2003. "Bos grunniens" (On-line), Animal Diversity Web. Accessed April 04, 2009)
4. ^ Wiener, Gerald, Han Jianlin, and Long Ruijun. "4 The Yak in Relation to Its Environment", The Yak, Second Edition. Bangkok: Regional Office for Asia and the Pacific Food and Agriculture Organization of the United Nations, 2003. ISBN 92-5-104965-3. Accessed 8 August 2008.
5. ^ Yak, Animal genetics training resources version II: Breed Information. Adopted from: Bonnemaire, J. "Yak". In: Mason, Ian L. (ed), Evolution of Domesticated Animals. London: Longman, 1984, pp. 39–45. ISBN 0582460468. Accessed 8 August 2008.
6. ^ http://science.jrank.org/pages/7436/Yak.html
7. ^ Paul Massicot, Animal Info - Wild Yak, March 5, 2005. Accessed 8 August 2008.
8. ^ Yak, Alaska Zoo.
9. ^ Tibet is My Country: Autobiography of Thubten Jigme Norbu, Brother of the Dalai Lama as told to Heinrich Harrer, p. 151. First published in German in 1960. English translation by Edward Fitzgerald, published 1960. Reprint, with updated new chapter, (1986): Wisdom Publications, London. ISBN 0-86171-045-2.
10. ^ Golden Book Encyclopedia, Vol. 16 p 1505b (Rockefeller Center, NY: Golden Press, 1959.)
11. ^ Tibet and Tibetan Foods
12. ^ Yaks, butter & lamps in Tibet, webexhibits.org
13. ^ Cai Li et al., 1980, The good meat-purpose yak - the investigation and study of Jiulong Yak. Journal of China Yak, 1: 14-33. (quoted in The Yak, Second Edition, 2003, FAO: Chapter 6: Production Characteristics of Yak; Section: Fibre production and hides [1])

External links

Wikimedia Commons has media related to: Yak

Wikispecies has information related to: Yak

• ARKive - images and movies of the wild yak (Bos grunniens)
• h2g2 Yaks Edited Guide Entry
• International Yak Association (IYAK)
• European Yak Association (EYAK)
• Article on Yak breeds in FAO archives
• Yaks: The Official Animal of Tibet
• AnimalInfo.Org: Animal Info - Wild Yak