Taxonomic history

Carl Linnaeus first described the genus Bos and the water buffalo under the binomial Bubalis bubalus in 1758; the latter was known to occur in Asia and as a domestic form in Italy.^[15] Ellerman and Morrison-Scott treated the wild and domestic forms of the water buffalo as conspecifics^[16] whereas others treated them as different species.^[17] The nomenclatorial treatment of wild and domestic forms has been inconsistent and varies between authors and even within the works of single authors.^[18]
In March 2003, the International Commission on Zoological Nomenclature achieved consistency in the naming of wild and domestic water buffalo by ruling that the scientific name Bubalus arnee is valid for the wild form.^[19] B. bubalis continues to be valid for the domestic form and applies also to feral populations.^[20]

Domestication and breeding

Murrah buffalo at the Philippine Carabao Center

Water buffalo were domesticated in Indian subcontinent about 5000 years ago, and in China about 4000 years ago. Two types are recognized, based on morphological and behavioural criteria – the river buffalo of the Indian subcontinent and further west to the Balkans and Italy, and the swamp buffalo, found from Assam in the west through Southeast Asia to the Yangtze valley of China in the east.^[3] The present-day river buffalo is the result of complex domestication processes involving more than one maternal lineage and a significant maternal gene flow from wild populations after the initial domestication events.^[21] Twenty-two breeds of the river type water buffalo are known, including Murrah, NiliRavi, Surti, Jafarabadi, Anatolian, Mediterranean, and Egyptian buffalo.^[22] China has a huge variety of buffalo genetic resources, comprising 16 local swamp buffalo breeds in various regions.^[13]
Results of mitochondrial DNA analyses indicate that the two types were domesticated independently.^[23] Sequencing of cytochrome b genes of Bubalus species implies that the domestic buffalo originated from at least two populations, and that the river and the swamp types have differentiated at the full species level. The genetic distance between the two types is so large that a divergence time of about 1.7 million years has been suggested. The swamp type was noticed to have the closest relationship with the tamaraw.^[24]