These dolphins are the smallest of all cetaceans. It was only during the 1950s that the separate Indian Ocean population of this species was discovered.
Commerson's dolphins occur relatively close to the shore, often entering coastal inlets, and are very conspicuous. They also accompany boats. The species is named after the French naturalist Dr Philibert Commerson, who recorded them in the Straits of Magellan in 1766. Today, there are about 3400 of these dolphins in the region, while the genetically distinct Kerguelen population lies 8000 km (5000 miles) away.
There are two populations of Commerson's dolphin, one in the Indian Ocean, and a larger population along South America's Atlantic coast, from the Straits of Magellan to Rio Negro province in central Argentina. Commerson's dolphins generally live in small pods of about three individuals. Pods may herd together to form temporary assemblies of over 100 dolphins, probably for breeding or feeding purposes. Commerson's dolphins eats shrimp, fish, squid and invertebrates that live on the seabed.
Distribution: Two distinct populations exist. The largest is off southern South America and the Falkland Islands.
Weight: 35 - 60 kg (77 - 132 lb).
Length: 130 - 170 cm (48 - 68 in).
Maturity: 6 - 9 years.
Gestation Period: About 334 days; young are large - nearly half the size of their mothers at birth.
Breeding: 1; weaning may take over a year.
Food: Feeds on a variety of fish and squid, and also crustaceans.
Lifespan: Up to 18 years; more than 26 years in captivity.
This is long and straight along its upper surface, ending in a curved tip.
The whales have a streamlined, rounded facial shape, with broad jaws.
The tail fin in Commerson's dolphins has a notch in the middle of its outer edge.
There is a clear delineation between the black and white areas, with the white confined to the throat and body.
Females have a black arrowhead marking on their underparts, whereas that of the male resembles a teardrop.
Young are born grey, black and brown, and then become black and grey. The grey areas ultimately become white.