Early in the 19th century, a specimen was caught off the Cape of Good Hope and brought to the United Kingdom by a Captain Haviside of the British East India Company. Zoologist John Edward Gray, who described the species in his Spicilegia Zoologica, misidentified Haviside as the surgeon John Heaviside, whose collection was acquired roughly contemporaneously. "Heaviside's Dolphin" is most common in the literature, though some authorities use the originally intended name "Haviside's dolphin".
Population and distribution
Although sightings of the species are not uncommon off the Skeleton Coast of Namibia, Heaviside's dolphins have not been systematically studied by scientists. They have been recorded off the coast of northern Namibia at 17°S and as far south as the southern tip of South Africa. Sightings are often recorded from major population centres such as Cape Town and towns such as Walvis Bay. Sightings are likely from Lambert's Bay either from the shore or from boat trips run from the harbour. No estimates of abundance exist.
Physical description
Heaviside's dolphin is a fairly small dolphin, growing to about in length and weighing up to. Their size and the bluntness of their heads lead these dolphins to often be mistaken for porpoises. The head is coloured a dark grey. The front half of the upper side and the flanks are a much lighter grey. The dorsal fin, and back half of the back are again a darker grey colour. The underbelly is white, with flashes of white on the flanks below the dorsal fin. Males reach sexual maturity around 7 to 9 years old. Females reach breeding age at the same time. The gestation period is probably 10 months. Mating occurs in spring and summer. Females are believed to calve on average once every three years. The maximum known age of a Heaviside's dolphin is 20 years. This relatively short lifespan, coupled with the long calving period, causes a naturally low population growth rate. Therefore, the species is particularly sensitive to being hunted. Heaviside's dolphins are active and social animals. They typically congregate in groups of about five to 10 in number, but sometimes in larger groups. They are able to swim fast. Part of their play and social activity is to jump vertically clear of the water, turn in the air, and fall back into the sea with virtually no splashing or noise.
