This dolphin is named for its unique behavior of launching itself nose-first out of the water and spinning in the air up to five times before splashing down on its side. These acrobatics have been enjoyed by people for centuries. Sailors generally considered the presence of dolphins near their ships to be a good luck sign.
Spinner Dolphins are small compared to other cetaceans, with adults reaching up to 7.5 feet (2.3 m) in length. They can be identified by their triangular-shaped dorsal fin and sleek bodies. Most Spinner Dolphins display three colors, including a dark gray back, light grey sides and a pale belly. A dark band bordered by two pale stripes runs lengthwise down the body from the eye to the flippers. These patterns can change dramatically within the species depending on where they are located geographically.
Like most cetaceans, Spinner Dolphins live out their lives in family groups known as pods. They are highly social and work cooperatively when hunting or defending themselves from predators such as sharks. This species is well-known for its friendliness and curiosity and will often approach boats and swimmers. In areas such as Hawaii, snorkeling with Spinner Dolphins is a popular recreational activity.
The Spinner Dolphin is a warm-water species found in tropical and subtropical waters throughout the world. Most populations are open sea and deep-water hunters, although those in the Hawaiian Islands tend to prefer more coastal areas and will often rest during the day in bays and coves, returning to the open sea at night.
As with many cetaceans, the Spinner Dolphin saw huge declines in its numbers prior to worldwide whaling bans imposed in the mid-twentieth century. It’s likely that some populations of this species were reduced as much as 50% due to over-harvesting or accidental by-catch in tuna purse seine fishing nets. This changed after the tuna industry introduced its Dolphin-Safe Program. Additional threats to the animal’s survival include waterborne toxins such as DDT and polychlorinated biphenyl. Entanglement in marine debris is an ongoing issue for this marine mammal.
Today, the Spinner Dolphin is protected by both U.S. and international law and treaties. It is considered common in most of its range.