information:highlighting, structural:summarization
Characteristics

The skin of the river buffalo is black, but some specimens may have dark, slate-coloured skin. Swamp buffaloes have a grey skin at birth, which becomes slate blue later. Albinoids are present in some populations. River buffaloes have longer faces, smaller girths, and bigger limbs than swamp buffaloes. Their dorsal ridges extend further back and taper off more gradually. Their horns grow downward and backward, then curve upward in a spiral. Swamp buffaloes are heavy-bodied and stockily built, with a short body and large belly. The forehead is flat, the eyes are prominent, the face is short, and the muzzle is wide. The neck is comparatively long, and the withers and croup are prominent. A dorsal ridge extends backward and ends abruptly just before the end of the chest. Their horns grow outward and curve in a semicircle, but always remain more or less on the plane of the forehead. The tail is short, reaching only to the hocks. Size of the body and shape of horns may vary greatly among breeds. Height at the withers is 129–133 cm (51–52 in) for bulls and 120–127 cm (47–50 in) for cows, but large individuals may attain 160 cm (63 in). Head-lump length at maturity typically ranges from 240–300 cm (94–118 in) with a 60–100 cm (24–39 in) long tail. They range in weight from 300–550 kg (660–1,210 lb), but weights of over 1,000 kg (2,200 lb) have also been observed.

Tedong bonga is a piebald water buffalo featuring a unique black and white colouration that is favoured by the Toraja of Sulawesi.

The swamp buffalo has 48 chromosomes, while the river buffalo has 50 chromosomes. The two types do not readily interbreed, but fertile offspring can occur. Water buffalo-cattle hybrids have not been observed to occur, but the embryos of such hybrids reach maturity in laboratory experiments, albeit at lower rates than non-hybrids.

The rumen of the water buffalo differs from the rumen of other ruminants. It contains a larger population of bacteria, particularly the cellulolytic bacteria, lower protozoa, and higher fungi zoospores. In addition, higher levels of the rumen ammonia nitrogen (NH -N) and pH have been found compared to those in cattle.