Dolphins are very social organisms. Common dolphins are seldom alone. They travel together, they eat together, they even breathe together! The whole school can all be in the air at one time. Schools can contain as many as 1000 to 100,000 individuals. Common dolphins are the most abundant and wide spread species of dolphins.

In higher latitudes, when the first storms of fall move over the waters, females and their young assemble into large companies to face the vigors of winter. They depend on their large numbers to find food and on their speed and caution for protection. Males live apart from these large herds of females. Although they remain in the same area, they stay a considerable distance away until the warmer spring season approaches. Further separation of the sexes occurs in nursery schools of pregnant and nursing females.