The playful spinner dolphin makes itself known with a splash. Skilled acrobats, the small dolphins regularly leap out of the water and perform complicated aerial maneuvers. They can spin multiple times in one leap, which can be nearly 10 feet high.
The leaping and spinning likely serve several purposes, including the removal of irksome remoras, fish that latch on to eat parasites. Biologists also think the dolphins use their moves to communicate, each one signaling something different: “Let’s go” or “Danger!” or “I find you attractive.”
Like other dolphins, spinners also vocalize with whistles, echolocation clicks, and other sounds.
Spinner dolphins live in large pods from a few dozen to a thousand or more in tropical and subtropical zones around the world. They are the most abundant dolphin species in the Indian Ocean. Feeding on small fish, squid, and shrimp mostly at night in the open ocean, they return to the shallows during the day to rest and socialize.
Spinner dolphins sexually mature at around eight years old.
In the eastern tropical Pacific, spinner dolphins frequently swim together with schools of yellowfin tuna. Fishermen look for dolphin pods, knowing they’ll likely be with the tuna they want, and herd them with speedboats into a tight mass before deploying a large net over the pod. The dolphins are ensnared along with the tuna.
When the purse seine fishery first began around 1960, dolphins (not just spinners) trapped as bycatch were killed—a number estimated at around six million. Thanks to protection efforts, the dolphins today are usually released alive from the nets and the death rate is fairly low.