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Whales and Dolphins
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Whales, dolphins and porpoises are marine mammals. They are found throughout the world's seas, and in some tropical and subtropical rivers. They breathe air with lungs, are warm-blooded, and give birth to live young. They are threatened by hunting, fishing and other human activities.
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| Baleen whales |
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| Baleen whales have several hundred baleen plates instead of teeth. The plates filter food from sea water, including shrimps, other small crustaceans and small fish. Several baleen whale species are endangered, including the fin whale, sei whale and blue whale.
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|  | Grey whale
Grey whales are now restricted to the North Pacific ocean (along east and west coasts). The North Atlantic population is extinct.
They migrate in groups of up to 10, north to the Arctic for summer feeding and south to warm water lagoons to rest and produce calves in winter. It's thought that they may make the longest migrations of any mammal, up to 20,000km a year. Populations in the east pacific have risen since legal protection was introduced in 1946, however west pacific numbers are still low. According to the 2006 IUCN Red List, the Western Pacific stock is critically endangered. Numbers have been dramatically reduced by illegal hunting, ship collisions, entanglement in fishing gear as well as major off-shore developments of gas and oil fields. For more information about grey whales, see ARKive. |
| | North Pacific right whale
The North Pacific right whale is the most endangered of the large whales. This massive whale is at risk from collisions with ships and from fishing equipment because it swims slowly, dives for only a few minutes and feeds near the surface. North Pacific right whales are classified as endangered in the 2006 IUCN Red List. They were hunted to near extinction in the 1800s - they were called right whales because whalers considered them the right whales to hunt. They have been protected since 1937. However, large unreported kills by whalers in the 1950s and 1960s may have destroyed any chance of the right whale's recovery in the eastern and central North Pacific. |
| | Blue Whale
Blue whales are the largest animals to ever live on the planet. Antarctic whaling killed around 95% of the total population in the space of 60 years. Blue whales have been protected since 1967.Their almost exclusive dependance on food sources such as krill in the Antarctic makes blue whales vulnerable to large-scale changes in ocean productivity, which is likely to be the result of climate change. For more information about blue whales, see ARKive. |
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| Toothed whales |
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| The term toothed whale is used to describe several species, include the sperm whale, the narwhal, the beluga whale, dolphins and porpoises. Several smaller toothed whales are at risk.
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| | Ganges river dolphin
The Ganges river dolphin is endangered. Both sub species are extremely rare and they face numerous threats from humans.
This dolphin is effectively blind. It navigates and feeds using a sophisticated echolocation system. For more information about the Ganges river dolphin, see ARKive.
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| | Chinese river dolphin
The Chinese river dolphin is probably the most endangered cetacean in the world and is classed by the 2006 IUCN Red List as being critically endangered.
It faces a multitude of threats. Its prey is depleted by over-fishing, its migratory travel routes are blocked by dams. Other problems include collision with boats, pollution by chemicals and waste and engine noises that interfere with echolocation. It also has been hunted illegally for meat and for body parts that are used in traditional medicines.
For more information about the Chinese river dolphin, see ARKive.
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| | Gulf porpoise
The Gulf porpoise (vaquita) is critically endangered and one of the most vulnerable of all sea mammals. This small porpoise has a very restricted range in shallow waters less than 40m deep at the northern end of the gulf of California.
Entanglement in gill and trawl fishing nets is the principal threat to this mammal. Its habitat has also been drastically altered by the damming of the Colorado River in the United States.
For more information about the Gulf porpoise, see Wildfacts.
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| | Maui's dolphin
The Maui's dolphin (the North Island subspecies of the New Zealand Hector's dolphin) is the rarest and smallest marine dolphin. There are thought to be fewer than 100 left. Because they live in shallow waters and near harbours and river mouths, they are at particular risk from entanglement in fishing nets. For more information about the Maui's dolphin, see Wildfacts.
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