|Bos taurus , the domesticated cow|
|Genus:|| Bos |
| Bos taurus  |
See § Species.
Bos (from Latin bōs : cow, ox, bull) is the genus of wild and domestic cattle. Bos is often divided into four subgenera: Bos, Bibos, Novibos, and Poephagus, but including these last three divisions within the genus Bos without including Bison in the genus is believed to be polyphyletic by many workers on the classification of the genus since the 1980s. The genus as traditionally defined has five extant species  but this rises to eight when the domesticated varieties are counted as separate species, and 10 when the closely related genus Bison is also included.    Most but not all modern breeds of domesticated cattle are believed to have originated from the extinct aurochs.   Many ancient breeds are thought to have originated from other species. Zebus and taurine cattle are thought to descend from ancient Indian and Middle Eastern aurochs, respectively.
The species are grazers, with large teeth to break up the plant material they ingest. They are ruminants, having a four-chambered stomach that allows them to break down plant material. 
There are about 1.3 billion domestic cattle alive today, making them one of the world's most numerous mammals. Members of this genus are currently found in Africa, Asia, Europe, parts of North America, South America and also in Oceania. Their habitats vary greatly depending on the particular species; they can be found in prairies, rain forests, wetlands, savannah and temperate forests.
Most Bos species have a lifespan of 18–25 years in the wild, with up to 36 being recorded in captivity. They have a 9–11 month gestation, depending on the species and birth one or, rarely, two young in the spring.[ citation needed ]
Most species travel in small herds ranging in size from ten to thirty members. Within most herds, there is one bull (male) for all the cows (female). Dominance is important in the herds;  calves will usually inherit their mother's position in the hierarchy.[ citation needed ]
They are generally diurnal, resting in the hot part of the day and being active morning and afternoon. In areas where humans have encroached on the territory of a herd, they may turn nocturnal. Some species are also migratory, moving with food and water availability.[ citation needed ]
In 2003, the International Commission on Zoological Nomenclature resolved a long-standing dispute about the naming of those species (or pairs of species) of Bos that contain both wild and domesticated forms. The commission "conserved the usage of 17 specific names based on wild species, which are pre-dated by or contemporary with those based on domestic forms", confirming Bos primigenius for the aurochs and Bos gaurus for the gaur. If domesticated cattle and gayal are considered separate species, they are to be named Bos taurus and Bos frontalis; however, if they are considered part of the same species as their wild relatives, the common species are to be named Bos primigenius and Bos gaurus. 
During the 2010s, analysis of the complex genetics of the bovine lineages determined that the genus Bison needed to be relegated to a subgenus of Bos in order to retain monophyly within Bos since both extant species of Bison are phylogenetically embedded within Bos.  The specific relationships in these analyses determined that the two living bison species were each other's closest living relatives, with their closest relatives amongst Bos being the yaks based on nuclear DNA. The mitochondrial DNA for the wisent was found to contradict the nuclear DNA result, and was more closely related to those of cattle, while the mitochondrial DNA of the American bison supported the nuclear DNA result of a close relationship with yaks. The discrepancy between the mitochondrial DNA of the American bison and wisent is suggested to be likely due to incomplete lineage sorting or genetic introgression into B. bonasus from other Bos species.   
The following species are known:  
The aurochs is an extinct cattle species, considered to be the wild ancestor of modern domestic cattle. With a shoulder height of up to 180 cm (71 in) in bulls and 155 cm (61 in) in cows, it was one of the largest herbivores in the Holocene; it had massive elongated and broad horns that reached 80 cm (31 in) in length.
Bison are large bovines in the genus Bison within the tribe Bovini. Two extant and numerous extinct species are recognised.
The European bison or the European wood bison, also known as the wisent, the zubr, or sometimes colloquially as the European buffalo, is a European species of bison. It is one of two extant species of bison, alongside the American bison. The European bison is the heaviest wild land animal in Europe, and individuals in the past may have been even larger than their modern-day descendants. During late antiquity and the Middle Ages, bison became extinct in much of Europe and Asia, surviving into the 20th century only in northern-central Europe and the northern Caucasus Mountains. During the early years of the 20th century, bison were hunted to extinction in the wild.
The zebu, sometimes known in the plural as indicine cattle or humped cattle, is a species or subspecies of domestic cattle originating in the Indian sub-continent. Zebu are characterised by a fatty hump on their shoulders, a large dewlap, and sometimes drooping ears. They are well adapted to withstanding high temperatures, and are farmed throughout the tropical countries, both as pure zebu and as hybrids with taurine cattle, the other main type of domestic cattle. Zebu are used as draught and riding animals, dairy cattle, and beef cattle, as well as for byproducts such as hides and dung for fuel and manure. Some small breeds such as the miniature zebu are also kept as pets. In 1999, researchers at Texas A&M University successfully cloned a zebu.
Bovines comprise a diverse group of 10 genera of medium to large-sized ungulates, including cattle, bison, African buffalo, water buffalos, and the four-horned and spiral-horned antelopes. The evolutionary relationship between the members of the group is still debated, and their classification into loose tribes rather than formal subgroups reflects this uncertainty. General characteristics include cloven hooves and usually at least one of the sexes of a species having true horns. The largest extant bovine is the gaur.
The gaur, also known as the Indian bison, is a bovine native to South Asia and Southeast Asia, and has been listed as Vulnerable on the IUCN Red List since 1986. The global population was estimated at a maximum of 21,000 mature individuals in 2016, with the majority of those existing in India. It has declined by more than 70% during the last three generations, and is extirpated from Sri Lanka and most likely Bangladesh. Populations in well-protected areas are stable and increasing.
The domestic yak, also known as the Tartary ox, grunting ox or hairy cattle, is a species of long-haired domesticated cattle found throughout the Himalayan region of the Indian subcontinent, the Tibetan Plateau, Gilgit-Baltistan (Kashmir), Tajikistan and as far north as Mongolia and Siberia. It is descended from the wild yak.
The Heck or Munich-Berlin is a German breed or type of domestic cattle. It was bred in the 1920s by Heinz and Lutz Heck in an attempt to breed back the extinct aurochs. Controversy revolves around methodology and success of the programme. There are considerable differences between Heck cattle and the aurochs in build, height, and body proportions. Furthermore, there are other cattle breeds which resemble their wild ancestors at least as much as Heck cattle.
The gayal, also known as the Drung ox or mithun, is a large domestic cattle distributed in Northeast India, Bangladesh, Myanmar and in Yunnan, China.
The kouprey, also known as the forest ox, is a possibly extinct species of forest-dwelling wild bovine native to Southeast Asia. A young male was sent to the Paris Zoological Park in 1937 and was described by the French zoologist Achille Urbain who declared it the holotype. The kouprey has a tall, narrow body, long legs, a humped back and long horns.
The banteng, also known as tembadau, is a species of cattle found in Southeast Asia. The head-and-body length is between 1.9 and 3.68 m. Wild banteng are typically larger and heavier than their domesticated counterparts, but are otherwise similar in appearance. The banteng shows extensive sexual dimorphism; adult bulls are generally dark brown to black, larger and more sturdily built than adult cows, which are thinner and usually pale brown or chestnut red. There is a big white patch on the rump. Horns are present on both sexes, and are typically 60 to 95 cm long. Three subspecies are generally recognised.
A bovid hybrid is the hybrid offspring of members of two different species of the bovid family. There are 143 extant species of bovid, and the widespread domestication of several species has led to an interest in hybridisation for the purpose of encouraging traits useful to humans, and to preserve declining populations. Bovid hybrids may occur naturally through undirected interbreeding, traditional pastoral practices, or may be the result of modern interventions, sometimes bringing together species from different parts of the world.
The tribe Bovini, or wild cattle, are medium to massive bovines that are native to Eurasia, North America, and Africa. These include the enigmatic, antelope-like saola, the African and Asiatic buffalos, and a clade that consists of bison and the wild cattle of the genus Bos. Not only are they the largest members of the subfamily Bovinae, they are the largest species of their family Bovidae. The largest species is the gaur, weighing up to 1,500 kg (3,300 lb).
Sanga cattle is the collective name for indigenous cattle of sub-Saharan Africa. They are sometimes identified as a subspecies with the scientific name Bos taurus africanus. Their history of domestication and their origins in relation to taurine cattle, zebu cattle, and native African varieties of the ancestral aurochs are a matter of debate.
The Indian aurochs is an extinct aurochs subspecies that is considered the wild ancestor of the domestic zebu cattle, which is mainly found in the Indian subcontinent and has been introduced in many other parts of the world, like Africa and South America. In contrast, the domesticated taurine cattle breeds, which are native to Europe, the Near East, and other parts of the world, are descendants of the Eurasian aurochs. According to IUCN, the Indian aurochs disappeared before the 13th century AD, leaving only the Bos primigenius primigenius, whose range was by then restricted to Europe. The wild population of Indian aurochs was likely extinct millennia earlier than that; the most recent skeletal remains, from Uttar Pradesh, date from around 1,800 BC.
The wild yak is a large, wild bovine native to the Himalayas. It is the ancestor of the domestic yak.
The Uruz Project had the goal of breeding back the extinct aurochs. Uruz is the old Germanic word for aurochs. The Uruz Project was initiated in 2013 by the True Nature Foundation and presented at TEDx DeExtinction, a day-long conference organised by the Long Now Foundation with the support of TED and in partnership with National Geographic Society, to showcase the prospects of bringing extinct species back to life. The de-extinction movement itself is spearheaded by the Long Now Foundation.
Milovice Nature Reserve is a nature reserve next to the towns of Milovice and Benátky nad Jizerou in Nymburk District, Central Bohemian Region, Czech Republic. Established in 2015, the area is administered by the Česká krajina o.p.s. organization, as a part of Evropsky významná lokalita Milovice-Mladá CZ0214006 protected area, part of the European Union project Natura 2000. This reserve is a pioneering project of cooperation between several scientific bodies and draws support from many organizations and private sponsors.
Bubalina is a subtribe of wild cattle that includes the various species of true buffalo. Species include the African buffalo, the anoas, and the wild water buffalo. Buffaloes can be found naturally in sub-Saharan Africa, South Asia and Southeast Asia, and domestic and feral populations have been introduced to Europe, the Americas, and Australia. In addition to the living species, bubalinans have an extensive fossil record where remains have been found in much of Afro-Eurasia.
Bovina is a subtribe of the Bovini tribe that generally includes the two living genera, Bison and Bos. However, this dichotomy has been challenged recently by molecular work that suggests that Bison should be regarded as a subgenus of Bos. Wild bovinans can be found naturally in North America and Eurasia.