The dusky dolphin (Lagenorhynchus obscurus) is a medium sized dolphin, growing to lengths of 5.5 to 7 feet and weights of 150 to 185 pounds. It has a sloping face with no dominant beak nose. It is dark gray (or dark blue-gray) on its back and white on its belly. A pale gray stripe runs along its side and a forked pale pattern runs from its tail up towards its dorsal fin. The dorsal fin of the dusky dolpin is crescent-shaped.

The dusky dolphin inhabits cool waters ranging in temperature between 50 and 64 degrees F. It prefers waters that are less than 650 feet deep. Though locally common, it faces the threats of fishing bycatch and direct hunting as a human food source. Dusky dolphins often form groups of 6 to 15 individuals. They also are known to form feeding aggregations of several hundred individuals.