Beluga whale in the context of "Animal echolocation"

Porpoises (/ˈpɔːrpəsɪz/) are small dolphin-like cetaceans classified under the family Phocoenidae. Although similar in appearance to dolphins, they are more closely related to narwhals and belugas. There are eight extant species of porpoise, all among the smallest of the toothed whales. Porpoises are distinguished from dolphins by their flattened, spade-shaped teeth distinct from the conical teeth of dolphins, and lack of a pronounced beak, although some dolphins (e.g. Hector's dolphin) also lack a pronounced beak. Porpoises, and other cetaceans, belong to the clade Cetartiodactyla with even-toed ungulates.

Porpoises range in size from the vaquita, at 1.4 metres (4 feet 7 inches) in length and 54 kilograms (119 pounds) in weight, to the Dall's porpoise, at 2.3 m (7 ft 7 in) and 220 kg (490 lb). Several species exhibit sexual dimorphism in that the females are larger than males. They have streamlined bodies and two limbs that are modified into flippers. Porpoises use echolocation as their primary sensory system. Some species are well adapted for diving to great depths. As all cetaceans, they have a layer of fat, or blubber, under the skin to keep them warm in cold water.

Oceanic dolphins or Delphinidae are a widely distributed family of dolphins that live in the sea. Close to forty extant species are recognised. They include several big species whose common names contain "whale" rather than "dolphin", such as the Globicephalinae (round-headed whales, which include the false killer whale and pilot whale). Delphinidae is a family within the superfamily Delphinoidea, which also includes the porpoises (Phocoenidae) and the Monodontidae (beluga whale and narwhal). River dolphins are relatives of the Delphinoidea.

Oceanic dolphins range in size from the 1.7-metre-long (5 ft 7 in) and 50-kilogram (110-pound) Maui's dolphin to the 9.4-metre (31 ft) and 10-metric-ton (11-short-ton) orca, the largest known dolphin. Several species exhibit sexual dimorphism; the males are larger than females. They have streamlined muscular bodies and two limbs that are modified into flippers. Though not quite as flexible as seals, some dolphins can travel at speeds 29 km/h (18 mph) for short distances. Most delphinids primarily eat fish, along with a smaller number of squid and small crustaceans, but some species specialise in eating squid, or, in the case of the orca, also eat marine mammals and birds. All, however, are purely carnivorous. They typically have between 100 and 200 teeth, although a few species have considerably fewer. Delphinids travel in large pods, which may number a thousand individuals in some species. Each pod forages over a range of tens to hundreds of square kilometres. Some pods have a loose social structure, with individuals frequently joining or leaving, but others seem to be more permanent, perhaps dominated by a male and a harem of females. Individuals communicate by sound, producing low-frequency whistles, and also produce high-frequency broadband clicks of 80–220 kHz, which are primarily used for echolocation. Gestation lasts from 10 to 18 months, and results in the birth of a single calf. Some species are well adapted for diving to great depths. They have a layer of fat, or blubber, under the skin to keep warm in the cold water.

The polar bear (Ursus maritimus) is a large bear native to the Arctic and nearby areas. It is closely related to the brown bear, and the two species can interbreed. The polar bear is the largest extant species of bear and land carnivore by body mass, with adult males weighing 300–800 kg (660–1,760 lb). The species is sexually dimorphic, as adult females are much smaller. The polar bear is white- or yellowish-furred with black skin and a thick layer of fat. It is more slender than the brown bear, with a narrower skull, longer neck and lower shoulder hump. Its teeth are sharper and more adapted to cutting meat. The paws are large and allow the bear to walk on ice and paddle in the water.

Polar bears are both terrestrial and pagophilic (ice-living) and are considered marine mammals because of their dependence on marine ecosystems. They prefer the annual sea ice but live on land when the ice melts in the summer. They are mostly carnivorous and specialized for preying on seals, particularly ringed seals. Such prey is typically taken by ambush; the bear may stalk its prey on the ice or in the water, but also will stay at a breathing hole or ice edge to wait for prey to swim by. The bear primarily feeds on the seal's energy-rich blubber. Other prey include walruses, beluga whales and some terrestrial animals. Polar bears are usually solitary but can be found in groups when on land. During the breeding season, male bears guard females and defend them from rivals. Mothers give birth to cubs in maternity dens during the winter. Young stay with their mother for up to two and a half years.

The narwhal (Monodon monoceros) is a species of toothed whale native to the Arctic. It is the only member of the genus Monodon and one of two living representatives of the family Monodontidae. The narwhal is a stocky cetacean with a relatively blunt snout, a large melon, and a shallow ridge in place of a dorsal fin. Males of this species have a large (1.5–3.0 m (4 ft 11 in – 9 ft 10 in)) long tusk, which is a protruding left canine thought to function as a weapon, a tool for feeding, in attracting mates or sensing water salinity. Specially adapted slow-twitch muscles, along with the jointed neck vertebrae and shallow dorsal ridge allow for easy movement through the Arctic environment, where the narwhal spends extended periods at great depths. The narwhal's geographic range overlaps with that of the similarly built and closely related beluga whale, and the animals are known to interbreed.

Narwhals inhabit the Arctic waters of Canada, Greenland and Russia. Every year, they migrate to ice-free summering grounds, usually in shallow waters, and often return to the same sites in subsequent years. Their diet mainly consists of polar and Arctic cod, Greenland halibut, cuttlefish, shrimp, and armhook squid. Diving to depths of up to 2,370 m (7,780 ft), the narwhal is among the deepest-diving cetaceans. The animals typically travel in groups of three to eight, with aggregations of up to 1,000 occurring in the summer months. Narwhals mate among the offshore pack ice from March to May, and the young are born between July and August of the following year. When communicating amongst themselves, narwhals use a variety of clicks, whistles and knocks.

The cetacean family Monodontidae comprises two living whale species, the narwhal and the beluga whale and at least four extinct species, known from the fossil record. Beluga and narwhal are native to coastal regions and pack ice around the Arctic Ocean. Both species are relatively small whales, 3–5 m (9.8–16.4 ft) in length, with a forehead melon, and a short or absent snout. Premaxillary teeth are absent. They do not have a true dorsal fin, but do have a narrow ridge running along the back, which is much more pronounced in the narwhal. They are highly vocal animals, communicating with a wide range of sounds. Like other whales, they also use echolocation to navigate. Belugas can be found in the far north of the Atlantic and Pacific Oceans; the distribution of narwhals is restricted to the Arctic and Atlantic Oceans.

Monodontids have a wide-ranging carnivorous diet, feeding on fish, molluscs, and small crustaceans. They have reduced teeth, with the beluga having numerous simple teeth, and the narwhal having only two teeth, one of which forms the tusks in males. Gestation lasts 14–15 months in both species, and almost always results in a single calf. The young are not weaned for a full two years, and do not reach sexual maturity until they are five to eight years of age. Family groups travel as part of herds, or 'pods', which may contain several hundred individuals.

Aboriginal whaling or indigenous whaling is the hunting of whales by indigenous peoples recognised by either IWC (International Whaling Commission) or the hunting is considered as part of indigenous activity by the country. It is permitted under international regulation, but in some countries remains a contentious issue. (The hunting of smaller cetaceans is covered at Dolphin drive hunting.) It is usually considered part of the subsistence economy. In some places, whaling has been superseded by whale watching instead. This article deals with communities that continue to hunt; details about communities that have ended the practice may be found in History of whaling.

Whapmagoostui (Cree: ᐙᐱᒫᑯᔥᑐᐃ/Wâpimâkuštui, "place of the beluga") is the northernmost Cree village in Quebec, Canada, located at the mouth of the Great Whale River (French: Grande Rivière de la Baleine) on the coast of Hudson Bay in Nunavik. About 906 Cree with about 650 Inuit, living in the neighbouring village of Kuujjuarapik. The community is accessible only by air (Kuujjuarapik Airport) and, in late summer, by boat. Whapmagoostui is about 250 km (160 mi) north of the nearest Cree village, Chisasibi.

Although the permanent cohabitation of Inuit and Cree at the mouth of the Great Whale River goes back only 1950, the two nations were rubbing shoulders in the area for a very long time, with the Inuit close to the coast and the Cree more in the interior.