Narwhal in the context of "Unicorn"

Cabinets of curiosities (German: Kunstkammer [ˈkʊnstˌkamɐ] and Kunstkabinett [ˈkʊnstkabiˌnɛt]), also known as wonder-rooms (German: Wunderkammer [ˈvʊndɐˌkamɐ] ), were encyclopedic collections of objects whose categorical boundaries were, in Renaissance Europe, yet to be defined. Although more rudimentary collections had preceded them, the classic cabinets of curiosities emerged in the sixteenth century. The term cabinet originally described a room rather than a piece of furniture. Modern terminology would categorize the objects included as belonging to natural history (sometimes faked), geology, ethnography, archaeology, religious or historical relics, works of art (including cabinet paintings), and antiquities. In addition to the most famous and best documented cabinets of rulers and aristocrats, members of the merchant class and early practitioners of science in Europe formed collections that were precursors to museums.

Cabinets of curiosities served not only as collections to reflect the particular interests of their curators but also as social devices to establish and uphold rank in society. There are said to be two main types of cabinets. As R. J. W. Evans notes, there could be "the princely cabinet, serving a largely representational function, and dominated by aesthetic concerns and a marked predilection for the exotic," or the less grandiose, "the more modest collection of the humanist scholar or virtuoso, which served more practical and scientific purposes." Evans goes on to explain that "no clear distinction existed between the two categories: all collecting was marked by curiosity, shading into credulity, and by some sort of universal underlying design".

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.

Tusks are elongated, continuously growing front teeth that protrude well beyond the mouth of certain mammal species. They are most commonly canine teeth, as with narwhals, chevrotains, musk deer, water deer, muntjac, pigs, peccaries, hippopotamuses and walruses, or, in the case of elephants, elongated incisors. Tusks share common features such as extra-oral position, growth pattern, composition and structure, and lack of contribution to ingestion. In most tusked species both the males and the females have tusks although the males' are larger. Most mammals with tusks have a pair of them growing out from either side of the mouth. Tusks are generally curved and have a smooth, continuous surface. The male narwhal's straight single helical tusk, which usually grows out from the left of the mouth, is an exception to the typical features of tusks described above. Continuous growth of tusks is enabled by formative tissues in the apical openings of the roots of the teeth.

Other than mammals, dicynodonts are the only known vertebrates to have true tusks.

The ivory trade is the commercial, often illegal trade in the ivory tusks of the hippopotamus, walrus, narwhal, black and white rhinos, mammoth, and most commonly, African and Asian elephants.

Ivory has been traded for hundreds of years by people in Africa and Asia, resulting in restrictions and bans. Ivory was formerly used to make piano keys and other decorative items because of the white color it presents when processed but the piano industry abandoned ivory as a key covering material in the 1980s in favor of other materials such as plastic. Also, synthetic ivory has been developed which can be used as an alternative material for making piano keys.

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.