Mating happens within the school with no real mate selection. Adult females give live birth to one calf every 2 or 3 years. Gestation period averages 10.6 months. Behavior Spinner dolphins may occur in schools with as many as 1,000 individuals, but it is common to have 200 or fewer to a school. They are very social with each other and with other species of ocean dwellers.
Spinner dolphins rest in shallow waters, usually inlets.
They tend to go back to the same area each day. When they are done resting, they quickly swim out to the deep area to feed on the vertically migrating fauna. When they are in the deep, darker waters, they are more susceptible to predation. There is a dominance hierarchy within the schools of spinner dolphins. It is sustained by a descending order of threats and by behaviors that involve caresses.