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Risso's dolphin
Risso's dolphin (Grampus griseus) is the only species of the genus Grampus in the family Delphinidae (dolphins). Some of the most closely related species to these dolphins include: pilot whales (Globicephala spp.), pygmy killer whales (Feresa attenuata), melon-headed whales (Peponocephala electra), and false killer whales (Pseudorca crassidens). These dolphins grow to be about 10 ft in length and can be identified by heavy scarring that appears white. They are located worldwide in cold to temperate waters, but most typically found along continental shelves due to their eating habits. Risso's dolphins have a diet that contains primarily cephalopods. They are able to search for prey at various depths due to their ability to reach depths of almost 600 m (2,000 ft). Individuals typically travel in pods ranging from 10 to 50 dolphins, with which they form tight social bonds.
Like most marine species, Risso's dolphins suffer from anthropogenic disruptions to the environment. Pollution, both from noise and plastics, is a common cause of higher mortality rates. Many can be, or have been, affected by entanglement in fishing nets and whaling. Risso's dolphins are currently protected in the United States, but they are still hunted in other parts of the world.
Risso's dolphin is named after Antoine Risso, whose study of the animal formed the basis of the recognized description by Georges Cuvier in 1812. The holotype referred to a specimen at the Muséum national d'histoire naturelle, an exhibit using preserved skin and skull obtained at Brest, France.
The type and sole species of the genus Grampus refers to Delphinus griseus Cuvier 1812. A proposition to name this genus Grampidelphis in 1933, when the taxonomic status of "blackfish" was uncertain, and conserving the extensive use of "Grampus" for the "killer" Orcinus orca", also suggested renaming this species (Grampidelphis exilis Iredale, T. & Troughton, E. le G. 1933). These were recognised as synonyms after publication of the Catalog of Whales (Hershkovitz, 1966).
Another common name for Risso's dolphin is grampus (also the species' genus), although this common name was more often used for the orca. The etymology of the word "grampus" is unclear. It may be an agglomeration of the Latin grandis piscis or French grand poisson, both meaning big fish. The specific epithet griseus refers to the mottled (almost scarred) grey colour of its body.
Risso's dolphin has a relatively large anterior body and dorsal fin, while the posterior tapers to a relatively narrow tail. The bulbous shape of the head has a vertical crease in front.
Infants are dorsally grey to brown and ventrally cream-colored, with a white, anchor-shaped area between the pectorals and around the mouth. In older calves, the nonwhite areas darken to nearly black, and then lighten (except for the always dark dorsal fin). Linear scars mostly from social interaction eventually cover the bulk of the body; scarring is a common feature of male-to-male competition in toothed whales, but Risso's dolphin tend to be unusually heavily scarred. The pronounced appearance of these scars results from the lack of repigmentation, which may be advantageous, as a display that reduces further challenges from other males. Older individuals appear mostly white. Most individuals have two to seven pairs of teeth, all in the lower jaw.
Length is typically 10 ft (3.0 m), although specimens may reach 13 ft (4.0 m). Like most dolphins, males are typically slightly larger than females. This species weighs 300–500 kg (660–1,100 lb), making it the largest species called "dolphin".
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Risso's dolphin AI simulator
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Risso's dolphin
Risso's dolphin (Grampus griseus) is the only species of the genus Grampus in the family Delphinidae (dolphins). Some of the most closely related species to these dolphins include: pilot whales (Globicephala spp.), pygmy killer whales (Feresa attenuata), melon-headed whales (Peponocephala electra), and false killer whales (Pseudorca crassidens). These dolphins grow to be about 10 ft in length and can be identified by heavy scarring that appears white. They are located worldwide in cold to temperate waters, but most typically found along continental shelves due to their eating habits. Risso's dolphins have a diet that contains primarily cephalopods. They are able to search for prey at various depths due to their ability to reach depths of almost 600 m (2,000 ft). Individuals typically travel in pods ranging from 10 to 50 dolphins, with which they form tight social bonds.
Like most marine species, Risso's dolphins suffer from anthropogenic disruptions to the environment. Pollution, both from noise and plastics, is a common cause of higher mortality rates. Many can be, or have been, affected by entanglement in fishing nets and whaling. Risso's dolphins are currently protected in the United States, but they are still hunted in other parts of the world.
Risso's dolphin is named after Antoine Risso, whose study of the animal formed the basis of the recognized description by Georges Cuvier in 1812. The holotype referred to a specimen at the Muséum national d'histoire naturelle, an exhibit using preserved skin and skull obtained at Brest, France.
The type and sole species of the genus Grampus refers to Delphinus griseus Cuvier 1812. A proposition to name this genus Grampidelphis in 1933, when the taxonomic status of "blackfish" was uncertain, and conserving the extensive use of "Grampus" for the "killer" Orcinus orca", also suggested renaming this species (Grampidelphis exilis Iredale, T. & Troughton, E. le G. 1933). These were recognised as synonyms after publication of the Catalog of Whales (Hershkovitz, 1966).
Another common name for Risso's dolphin is grampus (also the species' genus), although this common name was more often used for the orca. The etymology of the word "grampus" is unclear. It may be an agglomeration of the Latin grandis piscis or French grand poisson, both meaning big fish. The specific epithet griseus refers to the mottled (almost scarred) grey colour of its body.
Risso's dolphin has a relatively large anterior body and dorsal fin, while the posterior tapers to a relatively narrow tail. The bulbous shape of the head has a vertical crease in front.
Infants are dorsally grey to brown and ventrally cream-colored, with a white, anchor-shaped area between the pectorals and around the mouth. In older calves, the nonwhite areas darken to nearly black, and then lighten (except for the always dark dorsal fin). Linear scars mostly from social interaction eventually cover the bulk of the body; scarring is a common feature of male-to-male competition in toothed whales, but Risso's dolphin tend to be unusually heavily scarred. The pronounced appearance of these scars results from the lack of repigmentation, which may be advantageous, as a display that reduces further challenges from other males. Older individuals appear mostly white. Most individuals have two to seven pairs of teeth, all in the lower jaw.
Length is typically 10 ft (3.0 m), although specimens may reach 13 ft (4.0 m). Like most dolphins, males are typically slightly larger than females. This species weighs 300–500 kg (660–1,100 lb), making it the largest species called "dolphin".