They have blowholes (modified nostrils) located on top of their heads, through which air is taken in and expelled. Some species, such as the sperm whale, can stay underwater for up to 90 minutes.

Whales evolved from land-living mammals, and must regularly surface to breathe air, although they can remain underwater for long periods of time. Some species, such as sperm whales, are particularly well adapted for diving to great depths to catch squid and other favoured prey. They also have such keen hearing-whether above or below the surface of the water-that some can survive even if they are blind. Toothed whales, in contrast, have conical teeth adapted to catching fish or squid. Baleen whales also have a well-developed sense of smell. Because their heads are enormous-making up as much as 40% of their total body mass-and they have throat pleats that enable them to expand their mouths, they are able to take huge quantities of water into their mouth at a time. Several whale species exhibit sexual dimorphism, in that the females are larger than males.īaleen whales have no teeth instead, they have plates of baleen, fringe-like structures that enable them to expel the huge mouthfuls of water they take in while retaining the krill and plankton they feed on. The sperm whale is the largest toothed predator on Earth. Whales range in size from the 2.6 metres (8.5 ft) and 135 kilograms (298 lb) dwarf sperm whale to the 29.9 metres (98 ft) and 190 tonnes (210 short tons) blue whale, which is the largest known animal that has ever lived. Whales are fully aquatic, open-ocean animals: they can feed, mate, give birth, suckle and raise their young at sea. Odontocetes include the Monodontidae (belugas and narwhals), Physeteridae (the sperm whale), Kogiidae (the dwarf and pygmy sperm whale), and Ziphiidae (the beaked whales), as well as the six families of dolphins and porpoises which are not considered whales in the informal sense. Mysticetes include four extant (living) families: Balaenopteridae (the rorquals), Balaenidae (right whales), Cetotheriidae (the pygmy right whale), and Eschrichtiidae (the grey whale).

The two parvorders of whales, baleen whales (Mysticeti) and toothed whales (Odontoceti), are thought to have had their last common ancestor around 34 million years ago. Their closest non-cetacean living relatives are the hippopotamuses, from which they and other cetaceans diverged about 54 million years ago. Whales, dolphins and porpoises belong to the order Cetartiodactyla, which consists of even-toed ungulates. Dolphins and porpoises may be considered whales from a formal, cladistic perspective. all cetaceans apart from dolphins and porpoises. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. Whales (Balaena) are a widely distributed and diverse group of fully aquatic placental marine mammals. Superfamily Inioidea (South American river dolphins).Superfamily Platanistoidea (Asian river dolphins).Family Delphinidae (dolphins and porpoises).Superfamily Physeteroidea (sperm whales)Ĭladistically included but traditionally excluded taxa.You can follow LiveScience senior writer Stephanie Pappas on Twitter Follow LiveScience for the latest in science news and discoveries on Twitter and on Facebook. 'This finding opens very large perspectives for future investigations on dolphin learning processes and 'mental representations.''

The recordings are 'the first report of mimicries of sounds heard during special events produced by dolphins in a resting/sleeping context,' the researchers wrote in the journal. It's possible the dolphins are even asleep as they make the whale-like noises, meaning they are essentially sleep-talking in 'whale.' This suggests that they could be rehearsing their daily shows in their minds at night, the researchers reported online in the journal Frontiers in Comparative Psychology Dec. The Planète Sauvage dolphins, however, only make the whale sounds at night, most likely when they're sleeping or at least resting. Dolphins, like birds, are known copy-cats, but their mimicry has always been confined to the time right after hearing an odd sound, at least as far as anyone knew.

Whale song sleep