About Bubalus bubalis arnee (Kerr, 1792)
This subspecies includes two main types of water buffalo: river buffalo and swamp buffalo, which differ in physical traits, genetics, and ecology. River buffalo typically have black skin, though some individuals have dark slate-colored skin. They have longer faces, smaller girths, and larger limbs than swamp buffalo. Their dorsal ridges extend further back and taper off more gradually. Their horns grow downward and backward, then curve upward in a spiral. Their chromosome count is 50. River buffalo prefer deep water. Swamp buffalo are born with grey skin that darkens to slate blue as they mature. They are heavy-bodied and stockily built, with a short body, large belly, flat forehead, prominent eyes, short face, and wide muzzle. Their neck is comparatively long, with prominent withers and croup. A dorsal ridge extends backward and ends abruptly just before the end of the chest. Their horns grow outward and curve in a semicircle, staying roughly on the plane of the forehead. They have 48 chromosomes. Swamp buffalo prefer to wallow in mudholes that they make with their horns, and gain a thick coating of mud during this activity. Albinoid individuals occur in some populations of water buffalo. Overall, body size and horn shape vary greatly between breeds. Mature bulls have a withers height of 129–133 cm (51–52 in), while mature cows have a withers height of 120–127 cm (47–50 in); exceptionally large individuals can reach 160 cm (63 in) at the withers. Mature head to rump length ranges from 240–300 cm (94–118 in), with a tail length of 60–100 cm (24–39 in). Body weight ranges from 300–550 kg (660–1,210 lb), but individuals weighing over 1,000 kg (2,200 lb) have been recorded. The short tail reaches only to the hocks. Tedong bonga is a piebald water buffalo with unique black and white coloration that is favoured by the Toraja people of Sulawesi. The two types do not interbreed readily, but can produce fertile offspring when they do. No naturally occurring water buffalo-cattle hybrids have been observed, but embryos of such hybrids can reach maturity in laboratory experiments, though at lower rates than non-hybrid embryos. The water buffalo rumen differs from that of other ruminants: it holds a larger population of bacteria, particularly cellulolytic bacteria, fewer protozoa, and more fungal zoospores. It also has higher levels of rumen ammonia nitrogen (NH4-N) and a higher pH than the rumen of cattle. Both types are well-adapted to hot and humid climates, with winter temperatures as low as 0 °C (32 °F) and summer temperatures of 30 °C (86 °F) or higher. Access to water is important in hot weather, as they use wallows, rivers, or splashing water for thermoregulation. Some breeds are adapted to saline seaside shores and saline sandy terrain. Swamp buffalo generally reach reproductive maturity at an older age than river buffalo breeds. Young males in Egypt, India, and Pakistan are first mated around 3.0–3.5 years of age, but in Italy, males may be used for breeding as early as 2 years of age. Successful mating can continue until the animal is 12 years old or even older. A healthy mature river buffalo male can impregnate 100 females in a single year. Mating is strongly influenced by season, and heat stress reduces male libido. While water buffalo are polyoestrous, their reproductive efficiency varies widely throughout the year. Cows show clear seasonal changes in oestrus activity, conception rate, and calving rate. The age of first oestrus in heifers ranges from 13 to 33 months across breeds, but mating at first oestrus is often infertile, so breeding is usually deferred until heifers are 3 years old. Gestation lasts between 281 and 334 days, with most reports placing the typical range between 300 and 320 days. Swamp buffalo have a gestation period one to two weeks longer than river buffalo. It is not uncommon to find water buffalo that still work well at 30 years of age, and working lifespans of 40 years have been recorded.
