Spinner Dolphin

The spinner dolphin is sometimes referred to as the long-snouted dolphin, particularly in older texts, to distinguish it from the similar Clymene dolphin, which is often called the short-snouted spinner dolphin. The species was described by John Gray in 1828. The four named "subspecies" are: *Eastern spinner dolphin (S. l. orientalis), from the tropical eastern Pacific. *Central American or Costa Rican spinner dolphin (S. l. centroamericana), also found in the tropical eastern Pacific. *Gray's or Hawaiian spinner dolphin (S. l. longirostris), from the central Pacific Ocean around Hawaii but represents a mixture of broadly similar subtypes found worldwide. *Dwarf spinner dolphin (S. l. roseiventris), first found in the Gulf of Thailand. The species, though, displays greater variety than these subspecies might indicate. A hybrid form characterized by its white belly inhabits the eastern Pacific. Other less distinct groupings inhabit other oceans. The species name comes from the Latin word for long-beaked.

The spinner dolphin lives in nearly all tropical and subtropical waters between 40°N and 40°S. The species primarily inhabits coastal waters, islands, or banks. However, in the eastern tropical Pacific, spinner dolphins live far from shore. Spinner dolphins may use different habitats depending on the season. The spinner dolphin feeds mainly on small mesopelagic fish, squids, and sergestid shrimps, and will dive 200–300 m to feed on them. Spinner dolphins of Hawaii are nocturnal feeders and forage in deep scattering layers, which contain many species. The dwarf spinner dolphin may feed mostly on benthic fish in reefs and shallow water. They swim around the prey in a circle and a pair may swim through the circle to make a catch. They are susceptible to parasites, and are known to exhibit both external ones like barnacles and remoras, and internal ones, like nematodes, trematodes, cestodes and acanthocephalans.

Due to the spinner dolphin foraging and feeding at night, in certain regions, such as Hawaii and northern Brazil, dolphins spend the daytime resting in shallow bays near deep water. Spinner dolphins rest as a single unit, moving back and forth slowly in a tight formation but just out of contact with one another. These resting behaviors are observed for about four to five hours daily. During rest periods, spinner dolphins rely on vision rather than echolocation. Some individual dolphins do not always go to a bay to rest; however, in Hawaii, dolphins do seem to return to the same site each trip. Spinner dolphins live in an open and loose social organization. The spinner dolphins of Hawaii live in family groups, but also have associations with others beyond their groups. The spinner dolphin has a 10-month gestation period, and mothers nurse their young for one to two years. Females are sexually mature at four to seven years, with three-year calving intervals, while males are sexually mature at seven to 10 years. Spinner dolphins live for about 20-25 years. Breeding is seasonal, more so in certain regions than others. Although most spinner dolphins are found in the deeper waters offshore of the islands, the rest of the Hawaiʻi population has a more coastal distribution. During daytime hours, the island-associated stocks of Hawaiian spinner dolphins seek sanctuary in nearshore waters, where they return to certain areas to socialize, rest, and nurture their young.

Spinner dolphins are known for their acrobatics and aerial behaviors. A spinner dolphin comes out of the water front first and twists its body as it rises into the air. When it reaches its maximum height, the dolphin descends back into the water, landing on its side. A dolphin can make two to seven spins in one leap; the swimming and rotational speed of the dolphin as it spins underwater affects the number of spins it can do while airborne.

The protected status of spinner dolphins are CITES Appendix II and Marine Mammal Protection Act (MMPA) protected throughout its range as well as MMPA depleted in its eastern stock. of the Convention on the Conservation of Migratory Species of Wild Animals (CMS), since they have an unfavourable conservation status or would benefit significantly from international co-operation organized by tailored agreements. In addition, the spinner dolphin is covered by Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MoU) and the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia (Western African Aquatic Mammals MoU). Spinner dolphins are susceptible to disease and two of the recorded diseases within them are toxoplasmosis and cetacean morbillivirus. The number of cases reported however is fairly low in the species. and efforts are being made both to educate the public in order to minimise human impact on the dolphins, and to bring in regulations to govern these activities. In 2023, 33 swimmers were arrested for reportedly harassing dolphins off the coast of the Big Island of Hawaii. The swimmers reportedly broke federal law by swimming within 45 meters (50 yards) of the dolphins. The ban went into effect in 2021 due to dolphins not getting enough rest during the day to forage for food at night. The swimmers were caught by drone footage pursuing the dolphins as they tried to escape.

File:Spinners.png|Spinner dolphins at Ras Samadai File:A_pod_of_spinner_dolphins_in_the_Red_Sea.jpg|A pod of spinner dolphins in the Red Sea File:Spinner_Dolphin_Indian_Ocean_07-2017.jpg|Spinner Dolphin in the Indian Ocean File:Spinner_Dolphin_Alphonse_Atoll_07-2017.jpg|Spinner Dolphin at Alphonse Atoll File:SpinnerDolphinsoffKauai 1999-03-15.jpg|A pod of spinner dolphins in Kauai, Hawaii File:Stenella longirostris Lanai Hawaii.jpg|Spinner dolphin at Lanai Hawaii File:twist tail spin.jpg|Hawaiian spinner dolphin spinning File:Spinner Dolphin at midway.jpg|Spinner dolphin at Midway Atoll File:Spinner dolphins video.wmv.OGG|Spinner dolphins video taken at Midway Atoll File:Spinner dolphins (6741930935).jpg|Porpoising in Papahānaumokuākea Marine National Monument File:Spinner dolphins Kauai Hawaii (31339186057).jpg|Spinner dolphins next to Kauai, Hawaii