Physeter is a genus of toothed whales containing a single living species, the sperm whale (Physeter macrocephalus).[2] Two fossil species are currently known that are placed in the same genus: Physeter antiquus (5.3 – 2.6 mya) from the Pliocene of France,[3] and Physeter vetus (2.6 mya – 12 ka) from the Quaternary of Georgia.[4]

Temporal range: Zanclean – Recent
Physeter macrocephalus - skeleton
Skeleton of a sperm whale, the only extant member of the genus
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Infraorder: Cetacea
Family: Physeteridae
Subfamily: Physeterinae
Genus: Physeter
Linnaeus, 1758


  1. ^ "Physeter macrocephalus Linnaeus 1758 (sperm whale)". Fossilworks: Gateway to the Paleobiology Database. Retrieved 12 August 2018.
  2. ^ "Physeter Linnaeus 1758 (sperm whale)". Fossilworks.
  3. ^ "Physeter antiquus Gervais 1849". Fossilworks.
  4. ^ "Physeter vetus Leidy 1869". Fossilworks.

Acrophyseter is a genus of extinct sperm whales that lived in the Late Miocene off the coast of Peru comprising two species: A. deinodon and A. robustus. It is part of a group of macroraptorial sperm whales which all shared several features for the purpose of hunting large prey, such as deeply-rooted and thick teeth. Acrophyseter measured 3.9–4.3 metres (13–14 ft), making it the smallest raptorial sperm whale. Because of its short pointed snout, and its strong curved front teeth, it probably fed on the large marine vertebrates of its time, such as seals and other whales


In biodiversity informatics, a chresonym is the cited use of a taxon name, usually a species name, within a publication. The term is derived from the Greek χρῆσις chresis meaning "a use" and refers to published usage of a name.

The technical meaning of the related term synonym is for different names that refer to the same object or concept. As noted by Hobart and Rozella Smith, zoological systematists had been using "the term (synonymy) in another sense as well, namely in reference to all occurrences of any name or set of names (usually synonyms) in the literature." Such a "synonymy" could include multiple listings, one for each place the author found a name used, rather than a summarized list of different synonyms. The term "chresonym" was created to distinguish this second sense of the term "synonym." The concept of synonymy is furthermore different in the zoological and botanical codes of nomenclature.

A name that correctly refers to a taxon is further termed an orthochresonym while one that is applied incorrectly for a given taxon may be termed a heterochresonym.


Cryptozoology is a pseudoscience and subculture that aims to prove the existence of entities from the folklore record, such as Bigfoot, the chupacabra, or Mokele-mbembe. Cryptozoologists refer to these entities as cryptids, a term coined by the subculture. Because it does not follow the scientific method, cryptozoology is considered a pseudoscience by the academic world: it is neither a branch of zoology nor folkloristics. It was originally founded in the 1950s by zoologists Bernard Heuvelmans and Ivan T. Sanderson.

Scholars have noted that the pseudoscience rejected mainstream approaches from an early date, and that adherents often express hostility to mainstream science. Scholars have studied cryptozoologists and their influence (including the pseudoscience's association with Young Earth creationism), and have noted parallels in cryptozoology and other pseudosciences such as ghost hunting and ufology.

Dwarf sperm whale

The dwarf sperm whale (Kogia sima) is a sperm whale that inhabits temperate and tropical oceans worldwide, in particular continental shelves and slopes. It was first described by biologist Richard Owen in 1866, based on illustrations by naturalist Sir Walter Elliot. The species was considered to be synonymous with the pygmy sperm whale (Kogia breviceps) from 1878 until 1998. The dwarf sperm whale is a small whale, 2 to 2.7 m (6 ft 7 in to 8 ft 10 in) and 136 to 272 kg (300 to 600 lb), that has a gray coloration, square head, small jaw, and robust body. Its appearance is very similar to the pygmy sperm whale, distinguished mainly by the position of the dorsal fin on the body–nearer the middle in the dwarf sperm whale and nearer the back in the other.

The dwarf sperm whale is a suction feeder that mainly eats squid, and does this in small pods of typically 1 to 4 members. It is preyed upon by the killer whale (Orcinus orca) and large sharks such as the great white shark (Carcharodon carcharius). When startled, the whale can eject a cloud of red-brown fluid, similar to a squid. Most of what is known of the whale comes from beached individuals, as sightings in the ocean are rare. Many of these stranded whales died from parasitic infestations or heart failure.

The dwarf sperm whale is hunted in small numbers around Asia. It is more threatened by ingesting or getting entangled by marine debris. No global population estimate has been made, and so its conservation status by the International Union for Conservation of Nature (IUCN) is data deficient.

Hal Whitehead

Hal Whitehead is a biologist specializing in the study of the sperm whale (Physeter macrocephalus). Whitehead is professor at Dalhousie University. The primary field research vessel of his laboratory is the Balaena, a Valiant 40 ocean-going cruising boat, which normally does its work off the coast of Nova Scotia. Other marine mammals studied by Whitehead's laboratory include beluga whales, pilot whales, northern bottlenose whales, and bottlenose dolphins.

List of Arctic cetaceans

This is a list of Arctic cetaceans.

List of mammals of Madeira

This is a list of mammals of Madeira, concerning the indigenous mammals of the Portuguese archipelago of Madeira in the North Atlantic ocean. Besides the mammals on the islands, the coastal waters are host to at least nine species of dolphins and ten species of migrating cetaceans. These are protected in the 430,000 km2 Madeiran Marine Mammal Sanctuary.


Livyatan is an extinct genus of sperm whale containing one species: L. melvillei. Its name was inspired by the biblical sea monster Leviathan, and the author of the book Moby-Dick, Herman Melville, where the antagonist is a large sperm whale. It was found in the Pisco Formation of Peru and lived during the Tortonian stage of the Miocene epoch, about 9.9–8.9 million years ago (mya); however, a large tooth from Australia implies that either it or a close relative survived into the Pliocene, around 5 mya. It was a member of a group of hyper-predatory macroraptorial sperm whales (or "raptorial sperm whales") and was likely an apex predator, preying on whales, seals, and so forth. Characteristic of raptorial sperm whales, Livyatan had functional, enamel-coated teeth on the upper and lower jaws, as well as several adaptations for hunting large prey.

Its total length has been estimated to be about 13.5–17.5 m (44–57 ft), similar to the modern sperm whale (Physeter macrocephalus), making it one of the largest predators to have ever existed. The tallest tooth measured 36.2 cm (14.3 in), and is the largest tooth of any known animal, excluding tusks. It is distinguished from the other raptorial sperm whales by the basin on the skull, and how it spans the entire length of the snout. The spermaceti organ, contained in that basin, is thought to have been used in echolocation and communication, or for ramming prey and other sperm whales. The whale may have interacted with the large extinct shark megalodon (Carcharocles megalodon), competing with it for a similar food source. Its extinction was likely caused by a cooling event at the end of the Miocene which resulted in a drop in food populations. The formation where the whale has been found has also preserved a large assemblage of marine life, such as sharks and marine mammals.


Mosasaurus (; "lizard of the Meuse River") is a genus of mosasaurs, extinct carnivorous aquatic squamates. It existed during the Maastrichtian age of the late Cretaceous period, between about 70 and 66 million years ago, in western Europe and North America. The name means "Meuse lizard", as the first specimen was found near the Meuse River (Latin Mosa + Greek sauros lizard).

Physeter Rocks

Physeter Rocks (63°31′S 60°9′W) is a small group of rocks lying west of Ohlin Island, Palmer Archipelago, Antarctica. The rocks were photographed by Falkland Islands and Dependencies Aerial Survey Expedition (FIDASE), 1956–57, and mapped from these photos. They are named by the United Kingdom Antarctic Place-Names Committee (UK-APC) in 1960 after the sperm whale, Physeter catodon.

This article incorporates public domain material from the United States Geological Survey document "Physeter Rocks" (content from the Geographic Names Information System).


Physeterida is a rank that contains both Kogiidae and modern sperm whales and some extinct species. It was named by J. Grey in 1821. It is an unranked classification.


Physeteroidea is a superfamily that, today, includes three extant species of whales: the sperm whale, in the genus Physeter, and the pygmy sperm whale and dwarf sperm whale, in the genus Kogia. In the past, these genera have sometimes been united in a single family, the Physeteridae, with the two Kogia species in the subfamily Kogiinae; however, recent practice is to allocate the genus Kogia to its own family, the Kogiidae, leaving the Physeteridae as a monotypic (single extant species) family, although additional fossil representatives of both families are known.

Sperm whale

The sperm whale (Physeter macrocephalus) or cachalot is the largest of the toothed whales and the largest toothed predator. It is the only living member of 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.

The sperm whale is a pelagic mammal with a worldwide range, and will migrate seasonally for feeding and breeding. Females and young males live together in groups, while mature males (bulls) live solitary lives outside of the mating season. The females cooperate to protect and nurse their young. Females give birth every four to twenty years, and care for the calves for more than a decade. A mature sperm whale has few natural predators, although calves and weakened adults are sometimes killed by pods of orcas (killer whales).

Mature males average 16 metres (52 ft) in length but some may reach 20.5 metres (67 ft), with the head representing up to one-third of the animal's length. Plunging to 2,250 metres (7,382 ft), it is the second deepest diving mammal, following only the Cuvier's beaked whale.The sperm whale uses echolocation and vocalization as loud as 230 decibels (re 1 µPa m) underwater. It has the largest brain on Earth, more than five times heavier than a human's. Sperm whales can live for more than 60 years.Spermaceti (sperm oil), from which the whale derives its name, was a prime target of the whaling industry, and was sought after for use in oil lamps, lubricants, and candles. Ambergris, a solid waxy waste product sometimes present in its digestive system, is still highly valued as a fixative in perfumes, among other uses. Beachcombers look out for ambergris as flotsam. Sperm whaling was a major industry in the nineteenth century, immortalised in the novel Moby Dick. The species is protected by the International Whaling Commission moratorium, and is listed as vulnerable by the International Union for Conservation of Nature.


Tetrameridae is a family of spirurian nematodes. It is the smallest of the large genera making up the bulk of the superfamily Habronematoidea. Like all nematodes, they have neither a circulatory nor a respiratory system. They are parasites, chiefly of birds and cetaceans.

This family contains the largest known nematode: Placentonema gigantissima is several meters long and has been found in the placenta of the sperm whale (Physeter catodon).


Zygophyseter varolai is an extinct cetacean that lived during the Tortonian Age of the Late Miocene 11.2 to 7.6 million years ago, and was similar to the modern day sperm whale (Physeter macrocephalus). It is known from a single specimen from the Pietra Leccese Formation in Italy. It was a member of a stem group of fossil macroraptorial sperm whales (often shortened to "raptorial") Brygmophyseter, Acrophyseter, and Livyatan. It grew to be around 6.5 to 7 meters (21 to 23 ft) in length and shared some characteristics with other raptorials, such as large teeth with tooth enamel that were functional in both the upper and lower jaws. It also had a beak, the ability to echolocate prey, and could have probably swum faster than the modern day sperm whale which goes 4 kilometers per hour (2.5 mph). These were probably used in the capture of large prey, such as large fish, seals, and whales. In fact, its common name, killer sperm whale, refers to its feeding habits that would have had a resemblance to the modern day killer whale (Orcinus orca).


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