|
The Spinner Dolphin (Stenella longirostris) is a small dolphin found in off-shore tropical waters around the world. It is famous for its acrobatic displays in which they will spin longitudinally along their axis as they leap through the air. Image File history File links Download high resolution version (3601x2351, 567 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Spinner Dolphin ...
Image File history File links This is a lossless scalable vector image. ...
The conservation status of a species is an indicator of the likelihood of that species continuing to survive either in the present day or the future. ...
Image File history File links Status_iucn2. ...
Conservation Dependent (LR/cd) was an IUCN category assigned to species or lower taxa which were dependent on conservation efforts to prevent the taxon becoming threatened with extinction. ...
Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. ...
“Animalia†redirects here. ...
Typical Classes See below Chordates (phylum Chordata) are a group of animals that includes the vertebrates, together with several closely related invertebrates. ...
Subclasses & Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria Mammals (class Mammalia) are warm-blooded, vertebrate animals characterized by the production of milk in female mammary glands and the presence of hair, three middle ear bones used in hearing, and a neocortex region in the...
Orders[1] Magnorder Xenarthra: Cingulata (Armadillos) Pilosa (Sloths, True Anteaters) Magnorder Epitheria: Superorder Afrotheria: Afrosoricida (Tenrecs, etc. ...
Suborders Mysticeti Odontoceti Archaeoceti (extinct) (see text for families) The order Cetacea (IPA: , L. cetus, whale) includes whales, dolphins and porpoises. ...
Families See text The toothed whales (systematic name Odontoceti) form a suborder of the cetaceans. ...
Genera See text Oceanic dolphins are the members of the Delphinidae family of cetaceans. ...
Species Stenella attenuata Stenella frontalis Stenella longirostris Stenella clymene Stenella coeruleoalba Stenella is a genus in the dolphin family. ...
In biology, binomial nomenclature is the formal system of naming species. ...
John Edward Gray. ...
Year 1828 (MDCCCXXVIII) was a leap year starting on Tuesday (link will display the full calendar) of the Gregorian Calendar (or a leap year starting on Thursday of the 12-day slower Julian calendar). ...
Image File history File links Download high resolution version (1357x628, 35 KB) , User:Pcb21 after User:Vardion. ...
Genera See article below. ...
Taxonomy 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 discovered by John Gray in 1828. There are four named subspecies: Binomial name Stenella clymene Clymene Dolphin range The Clymene Dolphin (Stenella clymene), in some texts known as the Short-snouted Spinner Dolphin, is dolphin endemic to the Atlantic Ocean. ...
In zoology, as in other branches of biology, subspecies is the rank immediately subordinate to a species. ...
- Eastern Spinner Dolphin (S. l. orientalis), found in 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), found in the central Pacific around Hawaii but represents a mixed bag of broadly similar subtypes found throughout the world.
- Dwarf Spinner Dolphin (S. l. roseiventris), first found in the Gulf of Thailand.
However the species display a greater variety than these subspecies might indicate. A hybrid form characterized by its white belly is noted in the eastern Pacific. Other less distinct groupings have been identified in other oceans. The Gulf of Thailand is a gulf located in the South China Sea (Pacific Ocean), surrounded by the countries Malaysia, Thailand, Cambodia and Vietnam. ...
In biology, a species is one of the basic units of biodiversity. ...
The specific name comes from the Latin for long-beaked. Latin is an ancient Indo-European language originally spoken in Latium, the region immediately surrounding Rome. ...
Physical description The Spinner Dolphin is dark gray, with darker patches in the tail stock, back and throat. Usually it has creamy-white patch on the belly though this varies considerably. The beak is distinctively long and thin, with a dark tip. The fins too are lengthy for dolphins of this size. The dorsal fin is erect and even leans forward in older males found in the eastern Pacific. However this description has to be described as a little loose - Spinner Dolphins are the most variable in form of all cetaceans. Dorsal fin of an orca A dorsal fin is a fin located on the backs of fishes, whales, dolphins, and porpoises, as well as the (extinct) ichthyosaurs. ...
Suborders Mysticeti Odontoceti (see text) The order Cetacea includes whales, dolphins and porpoises. ...
Adults have varied in size from 129 cm to 235 cm and weight from 23 kg to 78 kg. The gestation period is 10 months. Individuals reach maturity at 4-7 years (females) and 7-10 years (males). Longevity is unknown.
Spinners congregate in groups that vary from just a few dolphins to great schools numbering in the thousands. They are consistently acrobatic and keen bow-riders. The reason for the creature's spinning is not known. One suggestion is that the great cauldron of bubbles created on exit and re-entry may act as a target for echolocation by other individuals in the school. It may also be simply play-acting. Individuals have been spotted completing at least 14 spinning jumps in quick succession.
In the Atlantic the Spinner may be mistaken for the Clymene Dolphin which also spins, but not to such a regular and dramatic extent. They may occasionally hybridize with other species such as Bottlenose Dolphin and both varieties of Spotted Dolphin. Sometimes male Bottlenoses may even chase and "gang-rape" a female Spinner. Binomial name Stenella clymene Clymene Dolphin range The Clymene Dolphin (Stenella clymene), in some texts known as the Short-snouted Spinner Dolphin, is dolphin endemic to the Atlantic Ocean. ...
Binomial name Tursiops truncatus Montagu, 1821 Bottlenose Dolphin range (in blue) The Bottlenose Dolphin is the most common and well-known dolphin, recent molecular studies showing it is in fact two species, Common Bottlenose Dolphin (Tursiops truncatus), and Indo-Pacific Bottlenose Dolphin (). It inhabits warm and temperate seas worldwide and...
Population and distribution Spinner Dolphins occur in pelagic tropical waters in all the world's major oceans. Although they mainly live in the open ocean, they are sometimes found near the shores of tropical island chains such as in the waters off Hawaii. Their greatest population density occurs between the Tropics of Cancer and Capricorn. Although described as pantropical the species roughly divides up into geographical areas corresponding to subspecies. The total population is unknown and was certainly dramatically reduced by fishing activity in the eastern Pacific, but is still regarded as endangered. The population is currently unknown. The pelagic zone is the part of the open sea or ocean comprising the water column, i. ...
The tropics are the geographic region of the Earth centered on the equator and limited in latitude by the two tropics: the Tropic of Cancer in the north and the Tropic of Capricorn in the southern hemisphere. ...
Capital Honolulu Largest city Honolulu Area Ranked 43rd - Total 10,931 sq mi (29,311 km²) - Width n/a miles (n/a km) - Length 1,522 miles (2,450 km) - % water 41. ...
Communication Dolphin sounds appear to be in the form of click-whistles and pulse sounds which are a mix of echolocation and communication. Echolocation sounds enable dolphins to track objects in dim or dark water and to, in effect, see much further than their eyes will allow. Their complex array of whistle sounds are the way that dolphins talk to one another. The spinners can even identify themselves with sounds they make while trailing bubbles from their blowholes -- sounds called signature whistles.
These spinner dolphins also communicate by slapping the water with various body parts. For instance, “nose-outs” occur when beak is thrust from the surface. This action is commonly used when the pod is emerging from a rest period. “Tail slaps” are often used to indicate impending danger or to signal a dive. Head slaps, side slaps, and back slaps are most frequently seen as the school begins to pick up speed. Last, and most spectacular, are the spins themselves. Many animals spin repeatedly, with each spin tending to get smaller and smaller, finally finishing up with an emphatic side slap.
The power of the spin comes from the tremendous acceleration under the water and the torque of the tail as the dolphin breaks the surface. The aftermath of the spin -- the sound of the slap, the splash on the surface, and the dense bubble cloud underwater, which even distant dolphins can pick up through their echolocation -- may be the real purpose of the spin.
Spinner dolphins maximize the effect of this splash by twisting around to land in a belly-flop, or back-flop. Spins are most frequently performed while the school is spread out across the water. A spinning dolphin may be signaling to the others: "here I am. . . . here is where I am going. . . " The effect of many dolphins spinning and leaping at once, defines what scientists call the envelope of the school -- that is, its size, direction, and speed of travel.That how dolphins communicate with each other.
Feeding Dolphins tend to do most of their hunting at night as the “scattering layer” of marine life, which has spent the day at depths of 3000 feet, rises toward the surface to feed on microscopic plant material. It is composed of fish, jellyfish, euphausiids (or krill), squid, shell-less snails, as well as copepods. Before diving into layer, the pod of dolphins gathers together in a kind of rally as if realizing that they are about to embark on a dangerous journey. Indeed, these dolphins are taking a great risk because other predators have gathered as well, such as sharks, which are natural predators of dolphins. The spinners form small subgroups and spread out across the sea. Time after time, the dolphins dive down into the utter darkness at 800 feet, or more. They do not use their teeth to chew but rather to grasp and immobilize their prey.
Despite being separated by several miles of water, the school still coordinates its activities through sound -- -and through spinning -- which reaches an explosive crescendo in the darkness of night. Using their echolocation, the spinners scan the darkness and, using their whistles, they call members of the school back together and can unite for defense. By dawn, the spinners regroup. Well-fed, they likely will move once again towards the shelter of nearby islands.
Human interaction Spinner Dolphins have been studied both in the wild and in captivity in Hawaii. Up to two million Spinner Dolphins, mostly eastern and white-bellied varieties, were killed in the thirty years after purse seine fishing for tuna was introduced in the 1950s. The process killed probably half of all Eastern Spinner Dolphins. See Pantropical Spotted Dolphin for a discussion. A seine is a large fishing net that hangs vertically in the water by attaching weights along the bottom edge and floats along the top. ...
A shoal of skipjack tuna Tuna are several species of ocean-dwelling fish in the family Scombridae, mostly in the genus Thunnus. ...
Binomial name Stenella attenuata (Gray, 1846) Pantropical Spotted Dolphin range The Pantropical Spotted Dolphin (Stenella attenuata) is a species of dolphin found in all the worlds temperate and tropical oceans. ...
Although not caught in purse seine nets, spinner dolphins in Hawaii can be subjected to multiple daily visits to their nearshore resting grounds. If continued without strong regulations, the magnitude of people desiring wild dolphin encounters and some not-so-ethical tour operators exploiting the proximity of nearshore dolphin habitats while guaranteeing up-close interactions may result in the "loving nature to death" syndrome as found in similar areas, e.g. the Orcas of the Pacific Northwest.
References - Cetacean Specialist Group (1996). Stenella longirostris. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 11 May 2006. Database entry includes a lengthy justification of why this species is dependent on conservation
- Spinner Dolphin by William F. Perrin in Encyclopedia of Marine Mammals pp. 1173-1175. ISBN 978-0-12-551340-1
- Whales Dolphins and Porpoises, Mark Carwardine, Dorling Kindersley Handbooks, ISBN 0-7513-2781-6
- National Audubon Society Guide to Marine Mammals of the World, Reeves, Stewart, Clapham and Powell, ISBN 0-375-41141-0
- Variation of spotted and spinner porpoise (genus Stenella) in the Eastern Pacific and Hawaii William F. Perrin
The IUCN Red List of Threatened Species (also known as the IUCN Red List and Red Data List), created in 1963, is the worlds most comprehensive inventory of the global conservation status of plant and animal species and can be found here. ...
The World Conservation Union or International Union for the Conservation of Nature and Natural Resources (IUCN) is an international organization dedicated to natural resource conservation. ...
External links |
Feeds |
Contact