Indo-Pacific humpback dolphins are medium-sized dolphins, ranging from 1.8 to 3 m in length and weighing 250 to 285 kg when fully grown. Indo-Pacific humpback dolphins in waters near southern Africa express sexual dimorphism, with males larger than females, but sexual dimorphism is not observed in other areas.
The dorsal fin and hump of Indo-Pacific humpbacked dolphins varies with geographical region. In eastern waters, the dorsal fin is short and sits on a wide base that gradually slopes into the body. The tip of the fin is lightly recurved, and the hump is only 5 to 10% of the total body length. In western waters, the dorsal fin is shorter and more recurved, however it sits atop a much wider and longer base that reaches to about 30% of the body length.
Coloration of Indo-Pacific humpbacked dolphins varies greatly with developmental stage and with geographic region. In general, subadults are a mottled grayish-pink color and calves are dark gray. Individuals found in southern African waters are typically dark gray with a lighter ventral surface. They develop a pinkish-white spot on the dorsal fin as they age. Calves in this region are much lighter than those of other regions. Individuals found in the northern Indian Ocean are more brownish-gray in color. In waters around China and other areas of southeast Asia, individuals are pure white, often with a pinkish tint. White Indo-Pacific humpback dolphins also often have a speckling of dark flecks on their body.
Range mass: 250 to 280 kg.
Range length: 1.8 to 3 m.
Sexual Dimorphism: sexes alike; male larger