Maximum length of 2.3 metres

Backside is black, sides are striped light and dark gray, belly is white

Dorsal fin is very curved towards the back, located in the middle of the back

Dorsal fin is bicoloured, dark grey and white

Very surface active, often leap clear of the water

Often move quickly in large groups

Will approach boats to bow ride

Very surface active, often leap clear of the water.

Pacific white-sided dolphins are a gregarious species, often seen in large groups. Group sizes range from 1 to 1000 (mean: 62, median: 15, mode: 6).

Will approach boats to bow ride.

In British Columbia, Pacific white-sided dolphins can be seen year-round and move inshore/offshore throughout the year. 

Pacific white-sided dolphins are opportunistic predators feeding on over 60 species of fish and 20 species of cephalopod. In BC, they feed on at least 13 different prey species, including salmon, herring, Pollock, shrimp, sablefish, smelt, and squid.  They forage cooperatively, though large groups may separate into smaller sub-groups for foraging purposes.  These feeding groups have been observed corralling and herding fish in a coordinated fashion.

Life expectancy is in the range of 37 to 46 years. Females have a gestation period of approximately 12 months and reach sexual maturity between 7 to 9 years.  Males reach sexual maturity around 10 years of age.  Most neonates are observed in the spring/summer season and are nursed for 8-10 months.  Females appear to have a slow calving interval of 4.67 years.

Pacific white-sided dolphins are often reported associating with other species.  One study in Monterey Bay, California reported half of all recorded sightings of Pacific white-sided dolphins were in association with another species.  In British Columbia’s inshore waters they are seen with resident killer whales, Steller sea lions, Dall’s porpoise and humpback whales, among other species.  Offshore they are often reported with northern right whale dolphins, Risso’s dolphins, common dolphins and short-finned pilot whales.

Pacific white-sided dolphins are preyed upon by transient (mammal-eating) killer whales and in some parts of their range by large sharks.