Maximum reported length for African specimens is 1.93 m for females and 1.81 m for males. Adult weights range from 40 to 80 kg, though birth weight is not known for the African population. Reported birth length ranges from 55 to 70 cm in other areas. African specimens tend to be larger than specimens from New Zealand, but smaller than those from Peru. The largest measured female from New Zealand is 1.78 m in length while the largest female specimen from Peru is 1.93 m.
Males are slightly smaller, but heavier.
This meso-pelagic species can be found in coastal or continental shelf areas associated with cool currents of the Southern Hemisphere. Other disjunct populations of duskies can be found around New Zealand, both the east and west coasts of South America, especially off Peru and Argentina, and around several oceanic islands including Tristan de Cunha and Amsterdam Islands. Spectacular leaps, somersaults and side slaps are common, and are often repeated many times in succession by an individual animal. Duskies also readily approach boats to bowride. These dolphins can be found in groups of over 1500 animals, though group sizes of 6-300 are more common.