[4][5] The Pacific white-sided dolphin was named by Smithsonian mammalogist Theodore Nicholas Gill in 1865.

[6] Genetic analysis by Frank Cipriano suggests the two species diverged around two million years ago.

From 1990 to 1991, a study conducted by Richard C. Ferrero and William A. Walker revealed the vast majority of Pacific white-sided dolphins that fell victim to the drift nets were between the ages of 8.3 and 11 when they sexually matured.

The dolphins appear to follow some sort of migratory pattern – on the eastern side they are most abundant in the Southern California Bight in winter, but further north (Oregon, Washington) in summer.

[6] However, the tendency of Pacific white-sided dolphins to approach boats complicates precise estimates via sampling.

[6][18] Members form a close-knit group and will often care for a sick or injured dolphin.

Animals that live in such large social groups develop ways to keep in touch, with each dolphin identifying itself by a unique name-whistle.

The studies also revealed that the different types of echolocations do vary based on the geographical locations; the first population of Pacific white-sided dolphins that were observed, inhabiting the waters near the Pacific United States seemed to more activity during the night while the second population of Pacific white-sided dolphins, that were also observed, inhabiting areas near Baja California, were observed to be more active during the day, possibly due the seasons and the dolphins' search for prey.

[21][22] The first sighting of the species on Commander Islands involved a single dolphin to travel along with a pod of killer whales in 2013.

In captivity, they tend to consume less amounts of food when compared to their wild counterparts, this could be the case due to the fact of temperatures changing in the water based on the seasons.