The water buffalo or domestic Asian water buffalo (Bubalus bubalis) is a large bovid originating in South Asia, Southeast Asia, and China.
The origins of the domestic water buffalo types are debated, although results of a phylogenetic study indicate that the swamp type may have originated in China and was domesticated about 4,000 years ago, while the river type may have originated from India and was domesticated about 5,000 years ago.
At least 130 million domestic water buffalo exist, and more human beings depend on them than on any other domestic animal. They are especially suitable for tilling rice fields [though largely supplanted by tractors today], and their milk is richer in fat and protein than that of dairy cattle.
The swamp buffalo has 48 chromosomes; the river buffalo has 50 chromosomes. The two types do not readily interbreed, but fertile offspring can occur. Buffalo-cattle hybrids have not been observed to occur, and the embryos of such hybrids do not reach maturity in laboratory experiments.