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. There could however, be more subspecies currently undescribed, and more research is needed in this topic. A hybrid form between the '''Gray's Spinner and Eastern Spinner''' called the White-Bellied Spinner lives in the eastern Pacific, characterized by its white belly. The species name comes from the Latin word for long-beaked. ==Description==

Spinner dolphins are small cetaceans with a slim build. Adults are typically 129–235 cm long and reach a body mass of 23–79 kg. This species has an elongated rostrum and a triangular or subtriangular dorsal fin. Spinner dolphins generally have tripartite color patterns. The dorsal area is dark gray, the sides light gray, and the underside pale gray or white. Also, a dark band runs from the eye to the flipper, bordered above by a thin, light line. However, the spinner dolphin has more geographic variation in form and coloration than other cetaceans. In the open waters of eastern Pacific, dolphins have relatively small skulls with short rostra. In these same subspecies, a dark dorsal cape dims their tripartite color patterns. In certain subspecies, some males may have upright fins that slant forward. Some populations of spinner dolphin found in the eastern Pacific have backwards-facing dorsal fins, and males can have dorsal humps and upturned caudal flukes. ==Ecology==

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. ==Behavior and life history==

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. 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. ==Conservation status==

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. ==Images==

A_spinner_dolphin_in_the_Red_Sea.jpg|in the Red Sea 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:Stenella longirostris Lanai Hawaii.jpg|Spinner dolphin at Lanai Hawaii File:twist tail spin.jpg|Hawaiian spinner dolphin spinning File:Spinner dolphins video.wmv.OGG|Spinner dolphins video taken at Midway Atoll File:Spinner dolphins (6741930935).jpg|Porpoising in Papahānaumokuākea Marine National Monument ==See also==