ORCA

Dusky dolphin

Lagenoryhnchus obscurus

1.5 - 2.2m

Dark grey

Teeth

Dorsal fin

Dusky dolphins are medium-sized grey and white dolphins with tall, curved dorsal fins. The sweeping white blaze on their flanks gives them a beautiful pattern that can be seen when they breach. They have dark 'lips', beak tip and patch around each eye. These patterns stand out on the lighter face. A dusky dolphins dorsal fin has a darker leading edge and a lighted coloured trailing edge. 

Key Features:

  • Sloped melon and short dark-coloured beak 

  • Tall, curved, two-toned dorsal fin 

  • Dark grey back, white undersides and grey patterning on the flank 

  • Fast swimmers, highly social energetic and acrobatic 

Behaviour

Dusky dolphins are incredibly social, fast-swimming and agile. They are regularly seen breaching, and are inquisitive, often approaching boats to bow ride. They are typically found in groups of no more than 20 individuals, but occasionally groups of 500-1000 are seen. Large groups of over 2000 animals have been sighted feeding off the coast of New Zealand, at times when their prey is plentiful between April-May. Adaptable in their feeding strategies and preferred prey, dusky dolphins will feed on a variety of prey including lantern fish, small schooling fish and squid. Dusky dolphins will work together, using a cooperative feeding technique to catch their prey. Breaching, leaping and acrobatic chasing are thought to help synchronise their cooperative movements.

Threats

The major threats facing the Dusky dolphin include entanglement in fishing gear, being caught as bycatch and the overfishing of their prey. The most significant bycatch occurs in Peruvian fisheries, and historically Peru and Chile have hunted this species for human consumption but also for use as shark bait. These hunts caused a severe decline in population numbers and have been banned since 1994. Like other dolphin species they are also threatened by the effects of pollution and climate change throughout their range. 

Distribution

Limited to the Southern Hemisphere, the dusky dolphin lives in cool coastal and temperate waters. They appear to prefer the continental shelf, but are also found in areas close to shore where there is deeper water close by. 

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