Despite the controversial nature of the hunt resulting in international criticism, and the possible health risk that the often polluted meat causes, thousands of dolphins are caught in drive hunts each year.

Like every mammal, dolphins are warm blooded.

Dolphins can, however, establish strong social bonds; they will stay with injured or ill individuals, even helping them to breathe by bringing them to the surface if needed. The blowhole seals using strong muscles after an inhale to ensure no water gets in to the animals’ lungs when it is underwater. These conical teeth are used to catch swift prey such as fish, squid or large mammals, such as seal. [179][180] Four countries – Chile, Costa Rica, Hungary, and India – have declared dolphins to be "non-human persons" and have banned the capture and import of live dolphins for entertainment. Dolphin is a common name of aquatic mammals within the infraorder Cetacea. Dolphins range in size from the 1.7 m (5 ft 7 in) long and 50 kg (110 lb) Maui's dolphin to the 9.5 m (31 ft 2 in) and 10 t (11 short tons) killer whale. [6][7] Living in water with strong currents and potentially dangerous floating debris, it must swim continuously to avoid injury. [167] Captives occasionally act aggressively towards themselves, their tankmates, or humans, which critics say is a result of stress.

Unlike fish, who breathe through gills, dolphins breathe air using lungs. Compared to many other species, however, dolphin behavior has been studied extensively, both in captivity and in the wild. How Many Types Of River Dolphins Live In The World Today? A 2006 survey found no individuals of the Yangtze river dolphin, which now appears to be functionally extinct.[137]. [115], Some disagree with these findings, arguing that the results of these tests are open to human interpretation and susceptible to the Clever Hans effect. [61], Dolphins also display culture, something long believed to be unique to humans (and possibly other primate species).

Dolphins are fast swimmers in comparison to seals which typically cruise at 9–28 km/h (5.6–17.4 mph); the killer whale (orca), in comparison, can travel at speeds up to 55.5 km/h (34.5 mph).

[66] The Cornwall Wildlife Trust records about one such death a year. The earliest campaigns with "dolphin safe" labels were initiated in the 1980s as a result of cooperation between marine activists and the major tuna companies, and involved decreasing incidental dolphin kills by up to 50% by changing the type of nets used to catch tuna. Overall, however, they tend to be dwarfed by other Cetartiodactyls.

[152] The Ancient Greeks welcomed dolphins; spotting dolphins riding in a ship's wake was considered a good omen.

Dolphin meat is consumed in a small number of countries worldwide, which include Japan[190] and Peru (where it is referred to as chancho marino, or "sea pork"). All mammals give birth to live young.

[107] The neocortex of many species is home to elongated spindle neurons that, prior to 2007, were known only in hominids. Dolphins have rather small, unidentifiable spouts. Dolphins are sometimes hunted in places such as Japan, in an activity known as dolphin drive hunting. All fish, including sharks, have tail fins that are aligned vertically. [116] They showed dolphins real-time footage of themselves, recorded footage, and another dolphin. [5], The term 'dolphin' can be used to refer to, under the parvorder Odontoceti, all the species in the family Delphinidae (oceanic dolphins) and the river dolphin families Iniidae (South American river dolphins), Pontoporiidae (La Plata dolphin), Lipotidae (Yangtze river dolphin) and Platanistidae (Ganges river dolphin and Indus river dolphin). [193], The Faroe Islands population was exposed to methylmercury largely from contaminated pilot whale meat, which contained very high levels of about 2 mg methylmercury/kg. From 1976 to 1997, 55 whales were taken from the wild in Iceland, 19 from Japan, and three from Argentina. Dolphin is a common name of aquatic mammals within the infraorder Cetacea. An area of Florida Keys National Marine Sanctuary is home to a resident group of bottlenose dolphins. The main difference between water mammals and land mammals, is that many, like dolphins, breath through blowholes instead of taking air through their mouths. [23], Archaeoceti is a parvorder comprising ancient whales. The behavior spreads mainly within generations, rather than being passed from mother to offspring. Conversely they are not fish as they lack gills, have horizontally aligned tails, and possess only one dorsal fin. These ancient whales are the predecessors of modern whales, stretching back to their first ancestor that spent their lives near (rarely in) the water. For other uses, see, marine mammals, closely related to whales and porpoises, CS1 maint: DOI inactive as of November 2020 (. Dolphins are common in Greek mythology, and many coins from ancient Greece have been found which feature a man, a boy or a deity riding on the back of a dolphin. [122] The Indus river dolphin has a sleep method that is different from that of other dolphin species. Porpoises belong to the family Phocoenidae and share a common ancestry with the Delphinidae. Here, dolphins drive fish towards fishermen waiting along the shore and signal the men to cast their nets. [140][141] In some parts of the world, such as Taiji in Japan and the Faroe Islands, dolphins are traditionally considered food and are killed in harpoon or drive hunts. Research in this field has suggested that cetaceans, among others, possess self-awareness.

Dolphins feed largely on fish and squid, but a few, like the killer whale, feed on large mammals, like seals. [181][182][183], A number of militaries have employed dolphins for various purposes from finding mines to rescuing lost or trapped humans. Though both sharks and dolphins have distinct back fins, sharks and other fish have additional, usually smaller dorsal fins as well. Reptiles, amphibians, fish … This consists of an experience with other dolphins that modifies the signal structure of an existing whistle sound. Dolphins are warm blooded, and have mammary glands. [112] The brain to body mass ratio in some is second only to humans. [41][42][43], Dolphins have two pectoral flippers, containing four digits, a boneless dorsal fin for stability, and a tail fin for propulsion.