Cetacea is an infraorder of aquatic mammals belonging to the order Artiodactyla 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(Balaena) 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.
Beaked whales are a family of cetaceans noted as being one of the least-known groups of mammals because of their deep-sea habitat, reclusive behavior and apparent low abundance. Only three or four of the 24 existing species are reasonably well-known. Baird's beaked whales and Cuvier's beaked whales were subject to commercial exploitation, off the coast of Japan, while the northern bottlenose whale was extensively hunted in the northern part of the North Atlantic in the late 19th and early 20th centuries.
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. 73 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).
True's beaked whale is a medium-sized whale in the genus Mesoplodon. It is native to the northern Atlantic Ocean. The common name is in reference to Frederick W. True, a curator at the United States National Museum.
The common dolphin is the most abundant cetacean in the world, with a global population of about six million. Despite this fact and its vernacular name, the common dolphin is not thought of as the archetypal dolphin, with that distinction belonging to the bottlenose dolphin due to its popular appearances in aquaria and the media. However, the common dolphin is often depicted in Ancient Greek and Roman art and culture, most notably in a mural painted by the Greek Minoan civilization.
The long-finned pilot whale is a large species of oceanic dolphin. It shares the genus Globicephala with the short-finned pilot whale. Long-finned pilot whales are known as such because of their unusually long pectoral fins.
The Cuvier's beaked whale, goose-beaked whale, or ziphius is the most widely distributed of all beaked whales in the family Ziphiidae. It is smaller than most baleen whales yet large among beaked whales. Cuvier's beaked whale is pelagic, inhabiting waters deeper than 300 m (1,000 ft). It has the deepest and longest recorded dives among whales at 2,992 m (9,816 ft) and 222 minutes, though the frequency and reasons for these extraordinary dives are unclear. Despite its deep-water habitat, it is one of the most frequently spotted beaked whales.
The four-toothed whales or giant beaked whales are beaked whales in the genus Berardius. They include Arnoux's beaked whale in cold Southern Hemispheric waters, and Baird's beaked whale in the cold temperate waters of the North Pacific. A third species, Sato's beaked whale, was distinguished from B. bairdii in the 2010s.
The melon-headed whale, also known less commonly as the electra dolphin, little killer whale, or many-toothed blackfish, is a toothed whale of the oceanic dolphin family (Delphinidae). The common name is derived from the head shape. Melon-headed whales are widely distributed throughout deep tropical and subtropical waters worldwide, but they are rarely encountered at sea. They are found near shore mostly around oceanic islands, such as Hawaii, French Polynesia, and the Philippines.
Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, often abbreviated to ASCOBANS, is a regional agreement on the protection of small cetaceans that was concluded as the Agreement on the Conservation of Small Cetaceans of the Baltic and North Seas under the auspices of the UNEP Convention on Migratory Species, or Bonn Convention, in September 1991 and came into force in March 1994. In February 2008, an extension of the agreement area came into force which changed the name to “Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas”. ASCOBANS covers all species of toothed whales (Odontoceti) in the Agreement Area, with the exception of the sperm whale.
The Húsavík Whale Museum is a non-profit organization established in 1997. The Húsavík Whale Museum is situated in Húsavík, a small town in north east Iceland, on the shores of Skjálfandi Bay, just below the Arctic Circle at 66° N. It began as a small exhibit on whales in the town's hotel in summer 1997. Shortly after that, the exhibition was moved into the newly renovated part of the baiting shed at the harbor and the shareholding business “Húsavík Whale Centre ehf” was established. Due to the growing popularity, it was obvious that a larger and more suitable building was needed after only 3 years. In 2000, the town's old slaughterhouse was purchased, remodeled, and officially opened in June 2002. In 2004, the shareholding business turned into a non-profit organization and was renamed “The Húsavík Whale Museum.” By 2005, a comprehensive exhibition on the ecology of whales was added.
The southern bottlenose whale is a species of whale, in the Ziphiid family, one of two members of the genus Hyperoodon. Seldom observed, the southern bottlenose whale is resident in Antarctic waters. The species was first described by English zoologist William Henry Flower in 1882, based on a water-worn skull from Lewis Island, in the Dampier Archipelago, Western Australia. They live in deep ocean waters over 1000 meters.
Cetaceans form an infra-order of marine mammals. In 2020, approximately 86 species of cetaceans had been identified worldwide. Among these species, at least 35 have been sighted in the wider Caribbean region with very widespread distribution and density variations between areas. Caribbean waters are a preferred breeding site for several species of mysticeti, who live further north the rest of the year. The tucuxi and the boto live at the southern periphery of the Caribbean region in the freshwaters of the Amazon river and surrounding drainage basins.
Natacha Aguilar de Soto is a Spanish marine biologist at the University of La Laguna (ULL), Tenerife, Canary Islands. She is a Ramón y Cajal research and teaching fellow at ULL and has been a Marie Skłodowska-Curie Research Fellow at ULL and at the Center for Research in Ecological Modeling (CREEM) of the University of St. Andrews (SMRU). She is the director of cetacean research within ULL's BIOECOMAC.
