Cetaceans are an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel themselves through the water with powerful up-and-down movement of their tail which ends in a paddle-like fluke, using their flipper-shaped forelimbs to maneuver.
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and porpoises. Dolphins and porpoises may be considered whales from a formal, cladistic perspective. Whales, dolphins and porpoises belong to the order Cetartiodactyla, which consists of even-toed ungulates. Their closest non-cetacean living relatives are the hippopotamuses, from which they and other cetaceans diverged about 54 million years ago. 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. Mysticetes include four extant (living) families: Balaenopteridae, Balaenidae, Cetotheriidae, and Eschrichtiidae. Odontocetes include the Monodontidae, Physeteridae, Kogiidae, and Ziphiidae, as well as the six families of dolphins and porpoises which are not considered whales in the informal sense.
The sperm whale or cachalot is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus Physeter and one of three extant species in the sperm whale family, along with the pygmy sperm whale and dwarf sperm whale of the genus Kogia.
Spermaceti is a waxy substance found in the head cavities of the sperm whale. Spermaceti is created in the spermaceti organ inside the whale's head. This organ may contain as much as 1,900 litres (500 US gal) of spermaceti. It has been extracted by whalers since the 17th century for human use in cosmetics, textiles, and candles.
The toothed whales are a parvorder of cetaceans that includes dolphins, porpoises, and all other whales possessing teeth, such as the beaked whales and sperm whales. Seventy-three species of toothed whales are described. They are one of two living groups of cetaceans, the other being the baleen whales (Mysticeti), which have baleen instead of teeth. The two groups are thought to have diverged around 34 million years ago (mya).
The pygmy sperm whale is one of two extant species in the family Kogiidae in the sperm whale superfamily. They are not often sighted at sea, and most of what is known about them comes from the examination of stranded specimens.
Bioacoustics is a cross-disciplinary science that combines biology and acoustics. Usually it refers to the investigation of sound production, dispersion and reception in animals. This involves neurophysiological and anatomical basis of sound production and detection, and relation of acoustic signals to the medium they disperse through. The findings provide clues about the evolution of acoustic mechanisms, and from that, the evolution of animals that employ them.
Whales use a variety of sounds for communication and sensation. The mechanisms used to produce sound vary from one family of cetaceans to another. Marine mammals, including whales, dolphins, and porpoises, are much more dependent on sound than land mammals due to the limited effectiveness of other senses in water. Sight is less effective for marine mammals because of the particulate way in which the ocean scatters light. Smell is also limited, as molecules diffuse more slowly in water than in air, which makes smelling less effective. However, the speed of sound is roughly four times greater in water than in the atmosphere at sea level. As sea mammals are so dependent on hearing to communicate and feed, environmentalists and cetologists are concerned that they are being harmed by the increased ambient noise in the world's oceans caused by ships, sonar and marine seismic surveys.
Cetacean stranding, commonly known as beaching, is a phenomenon in which whales and dolphins strand themselves on land, usually on a beach. Beached whales often die due to dehydration, collapsing under their own weight, or drowning when high tide covers the blowhole. Cetacean stranding has occurred since before recorded history.
This article discusses the history of whaling from prehistoric times up to the commencement of the International Whaling Commission (IWC) moratorium on commercial whaling in 1986. Whaling has been an important subsistence and economic activity in multiple regions throughout human history. Commercial whaling dramatically reduced in importance during the 19th century due to the development of alternatives to whale oil for lighting, and the collapse in whale populations. Nevertheless, some nations continue to hunt whales even today.
Scrimshaw is scrollwork, engravings, and carvings done in bone or ivory. Typically it refers to the artwork created by whalers, engraved on the byproducts of whales, such as bones or cartilage. It is most commonly made out of the bones and teeth of sperm whales, the baleen of other whales, and the tusks of walruses.
Whale oil is oil obtained from the blubber of whales. Whale oil from the bowhead whale was sometimes known as train oil, which comes from the Dutch word traan.
Whitlow W. L. Au was a leading expert in bioacoustics specializing in biosonar of odontocetes. He is author of the widely known book The Sonar of Dolphins (1993) and, with Mardi Hastings, Principles of Marine Bioacoustics (2008). Au was honored as a Fellow of the Acoustical Society of America in 1990 and awarded the ASA's first Silver Medal in Animal Bioacoustics in 1998. He was graduate advisor to MacArthur Fellow Kelly Benoit-Bird, who credits Au for discovering how sophisticated dolphin sonar is, developing dolphin-inspired machine sonars to separate different species of fish with the goal of protecting sensitive species, and for making numerous contributions to the description of Humpback whale song, which helped protect these whales from ship noise and ship traffic.
Nantucket shipbuilding began in the late 1700s and culminated in the construction of notable whaling ships during the early 19th century. Shipbuilding was predominantly sited at Brant Point. Whaling ship construction concluded in 1838.
Sperm whaling is the human practice of hunting sperm whales, the largest toothed whale and the deepest-diving marine mammal species, for the oil, meat and bone that can be extracted from the cetaceans' bodies.
The interactions between marine mammals and sonar have been a subject of debate since the invention of the technology.
Commercial whaling in Britain began late in the 16th century and continued after the 1801 formation of the United Kingdom and intermittently until the middle of the 20th century.
A drift whale is a cetacean mammal that has died at sea and floated into shore. This is in contrast to a beached or stranded whale, which reaches land alive and may die there or regain safety in the ocean. Most cetaceans that die, from natural causes or predators, do not wind up on land; most die far offshore and sink deep to become novel ecological zones known as whale falls. Some species that wash ashore are scientifically dolphins, i.e. members of the family Delphinidae, but for ease of use, this article treats them all as "drift whales". For example, one species notorious for mass strandings is the pilot whale, also known as "blackfish", which is taxonomically a dolphin.
Lord Hawkesbury was launched in the United States in 1781, probably under another name. She entered Lloyd's Register in 1787. She made six voyages as a whaler. On her second whaling voyage she "the first parcel of ambergris 'by any English whaler'". She was lost on the seventh after a squadron of French naval vessels had captured her. One of her original, British crew succeeded in regaining sufficient control from her prize crew to enable him to run her aground, wrecking her.
Bertel Møhl was a Danish marine zoologist and physiologist. He contributed significantly to the understanding of auditory physiology and bioacoustics of bats and marine mammals.
