Otters are carnivorous

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur ...

s in the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus Genus ( plural genera ) is a taxonomic rank used in the biological classifica ...

Lutrinae. The 13 extant otter

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

are all semiaquatic, aquatic, or

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military ...

, with diets based on

fish Fish are Aquatic animal, aquatic, craniate, gill-bearing animals that lack Limb (anatomy), limbs with Digit (anatomy), digits. Included in this definition are the living hagfish, lampreys, and Chondrichthyes, cartilaginous and bony fish as we ...

and

invertebrates Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordat ...

. Lutrinae is a branch of the Mustelidae

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

, which also includes

weasel Weasels are mammals of the genus ''Mustela'' of the family Mustelidae. The genus ''Mustela'' includes the least weasels, polecats, stoats, ferrets and European mink. Members of this genus are small, active predators, with long and slend ...

s, badgers,

mink Mink are dark-colored, semiaquatic, carnivorous mammals of the genera '' Neogale'' and '' Mustela'' and part of the family Mustelidae, which also includes weasels, otters, and ferrets. There are two extant species referred to as "mink": ...

, and

wolverine The wolverine (), (''Gulo gulo''; ''Gulo'' is Latin for " glutton"), also referred to as the glutton, carcajou, or quickhatch (from East Cree, ''kwiihkwahaacheew''), is the largest land-dwelling species of the family Mustelidae. It is a musc ...

s, among other animals.

Etymology

The word ''otter'' derives from the

Old English Old English (, ), or Anglo-Saxon, is the earliest recorded form of the English language, spoken in England and southern and eastern Scotland in the early Middle Ages. It was brought to Great Britain by Anglo-Saxon settlers in the mid-5th ...

word or . This, and cognate words in other

Indo-European languages The Indo-European languages are a language family native to the overwhelming majority of Europe, the Iranian plateau, and the northern Indian subcontinent. Some European languages of this family, English, French, Portuguese, Russian, D ...

, ultimately stem from the

Proto-Indo-European language Proto-Indo-European (PIE) is the reconstructed common ancestor of the Indo-European language family. Its proposed features have been derived by linguistic reconstruction from documented Indo-European languages. No direct record of Proto-Indo-E ...

root , which also gave rise to the English word "water".

Terminology

An otter's den is called a holt or couch. Male otters are called dogs or boars, females are called bitches or sows, and their offspring are called pups or cubs. The collective nouns for otters are bevy, family, lodge, romp (being descriptive of their often playful nature) or, when in water, raft. The

feces Feces ( or faeces), known colloquially and in slang as poo and poop, are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a rela ...

of otters are typically identified by their distinctive aroma, the smell of which has been described as ranging from freshly mown hay to putrefied fish; these are known as

spraint Spraint is the dung of the otter. Spraints are typically identified by smell and are known for their distinct odors, the smell of which has been described as ranging from freshly mown hay to putrefied fish. The Eurasian otter The Eurasian ott ...

Life cycle

The gestation period in otters is about 60 to 86 days. The newborn pup is cared for by the bitch, dog, and older offspring. Bitch otters reach sexual maturity at approximately two years of age and males at approximately three years. The holt is built under tree roots or a rocky cairn, more common in Scotland. It is lined with moss and grass. After one month, the pup can leave the holt and after two months, it is able to swim. The pup lives with its family for approximately one year. Otters live up to 16 years; they are by nature playful, and frolic in the water with their pups. Its usual source of food is fish, and further downriver, eels, but it may sample frogs and birds.

Description

Otters have long, slim bodies and relatively short limbs. Their most striking anatomical features are the powerful webbed feet used to swim, and their seal-like abilities holding breath underwater. Most have sharp claws on their feet and all except the sea otter have long, muscular tails. The 13 species range in adult size from in length and in weight. The Asian small-clawed otter is the smallest otter species and the giant otter and

sea otter The sea otter (''Enhydra lutris'') is a marine mammal native to the coasts of the northern and eastern North Pacific Ocean. Adult sea otters typically weigh between , making them the heaviest members of the weasel family, but among the smal ...

are the largest. They have very soft, insulated underfur, which is protected by an outer layer of long guard hairs. This traps a layer of air which keeps them dry, warm, and somewhat buoyant under water. Several otter species live in cold waters and have high

metabolic rate Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...

s to help keep them warm. European otters must eat 15% of their body weight each day, and

s 20 to 25%, depending on the temperature. In water as warm as , an otter needs to catch of fish per hour to survive. Most

hunt for three to five hours each day and

nursing Nursing is a profession within the health care sector focused on the care of individuals, families, and communities so they may attain, maintain, or recover optimal health and quality of life. Nurses may be differentiated from other health ...

mothers up to eight hours each day.

Feeding

For most otters, fish is the staple of their diet. This is often supplemented by frogs, crayfish and crabs. Some otters are experts at opening shellfish, and others will feed on available small mammals or birds. Prey-dependence leaves otters very vulnerable to prey depletion. Sea otters are hunters of

clams Clam is a common name for several kinds of bivalve molluscs. The word is often applied only to those that are edible and live as infauna, spending most of their lives halfway buried in the sand of the seafloor or riverbeds. Clams have two she ...

sea urchins Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of ...

and other shelled creatures. They are notable for their ability to use stones to break open shellfish on their stomachs. This skill must be learned by the young. Otters are active hunters, chasing prey in the water or searching the beds of rivers, lakes or the seas. Most species live beside water, but river otters usually enter it only to hunt or travel, otherwise spending much of their time on land to prevent their fur becoming waterlogged. Sea otters are considerably more aquatic and live in the ocean for most of their lives. Otters are playful animals and appear to engage in various behaviors for sheer enjoyment, such as making waterslides and then sliding on them into the water. They may also find and play with small stones. Different species vary in their social structure, some being largely solitary, while others live in groups – in a few species these groups may be fairly large.

Species

Extant species

Extinct species

Subfamily Lutrinae * Genus '' Lutra '' ** †'' Lutra castiglionis'' –

Corsica Corsica ( , Upper , Southern ; it, Corsica; ; french: Corse ; lij, Còrsega; sc, Còssiga) is an island in the Mediterranean Sea and one of the 18 regions of France. It is the fourth-largest island in the Mediterranean and lies southeast of ...

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

** †'' Lutra euxena'' –

Malta Malta ( , , ), officially the Republic of Malta ( mt, Repubblika ta' Malta ), is an island country in the Mediterranean Sea. It consists of an archipelago, between Italy and Libya, and is often considered a part of Southern Europe. It lies ...

, Pleistocene ** †'' Lutra nippon'' – Japan, extinct c. 1979'' * Genus '' Lutrogale'' ** †'' Lutrogale cretensis'' * Genus '' Enhydra'' ** †''

Enhydra reevei ''Enhydra'' is a genus of mustelid that contains the sea otter and two extinct relatives. It is the only extant genus of the bunodont otters group, referring to otters with non-blade carnassials with rounded cusps. Sea otters probably diverged f ...

'' * Genus †'' Algarolutra'' – Corsica and

Sardinia Sardinia ( ; it, Sardegna, label=Italian, Corsican and Tabarchino ; sc, Sardigna , sdc, Sardhigna; french: Sardaigne; sdn, Saldigna; ca, Sardenya, label= Algherese and Catalan) is the second-largest island in the Mediterranean Sea, aft ...

, Pleistocene * Genus †'' Cyrnaonyx'' – Europe, Pleistocene * Genus †'' Enhydriodon'' – Ethiopia, Late

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Enhydritherium'' – North America, Late Miocene to Early Pliocene * Genus †'' Limnonyx'' – Germany, Late Miocene * Genus †'' Megalenhydris'' – Sardinia, Pleistocene * Genus †'' Paludolutra'' – Italy, Late Miocene * Genus †'' Sardolutra'' – Sardinia, Pleistocene * Genus †''

Siamogale ''Siamogale'' is an extinct genus of giant otter from the late Miocene-early Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58

'' – eastern Asia, Late Miocene to Early Pliocene * Genus †'' Sivaonyx'' – Asia and Africa, Late Miocene to Early Pliocene * Genus †'' Teruelictis'' – Spain, Late Miocene * Genus †'' Torolutra'' – Africa, Pliocene * Genus †'' Tyrrhenolutra'' – Italy, Late Miocene * Genus †'' Vishnuonyx'' – Europe, Asia and Africa, Late Miocene to Early Pliocene

European otter

The European otter (''Lutra lutra''), also called the Eurasian otter, inhabits Europe, most of Asia and parts of North Africa. In the

British Isles The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isl ...

, they were common as recently as the 1950s, but became rare in many areas due to the use of chlorinated hydrocarbon

pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and ...

habitat loss Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

and water pollution (they remained relatively common in parts of Scotland and Ireland). Population levels reached a low point in the 1980s, but are now recovering strongly. The UK Biodiversity Action Plan envisages the re-establishment of otters by 2010 in all the UK rivers and coastal areas they inhabited in 1960. Roadkill deaths have become one of the significant threats to the success of their re-establishment.

North American river otter

The North American river otter (''Lontra canadensis'') became one of the major animals hunted and trapped for fur in North America after European contact. River otters eat a variety of fish and shellfish, as well as small land mammals and birds. They grow to one meter (3 to 4 ft) in length and weigh from five to 15 kilograms (10 to 30 lb). In some areas, the North American river otter is a protected species, and some places have otter sanctuaries that help sick and injured otters to recover.

Sea otter

Sea otters (''Enhydra lutris'') are classified as

marine mammal Marine mammals are aquatic mammals that rely on the ocean and other marine ecosystems for their existence. They include animals such as seals, whales, manatees, sea otters and polar bears. They are an informal group, unified only by their ...

s and live along the Pacific coast of North America. Their historic range included shallow waters of the Bering Strait and Kamchatka, and as far south as Japan. Sea otters have about 26,000 to 165,000 hairs per square centimeters of skin, a rich fur for which humans hunted them almost to extinction. By the time the 1911 Fur Seal Treaty gave them protection, so few sea otters remained that the fur trade had become unprofitable. Sea otters eat shellfish and other

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chorda ...

s (especially clams,

abalone Abalone ( or ; via Spanish , from Rumsen ''aulón'') is a common name for any of a group of small to very large marine gastropod molluscs in the family Haliotidae. Other common names are ear shells, sea ears, and, rarely, muttonfish or mutto ...

, and sea urchins). Otter populations are affected by the density of prey they hunt. Because the otter food source is easier to excavate from rocky-bottom habitats, as opposed to soft-bottom habitats, more otters tend to live in waters with rocky bottoms with access to shallow-burrowing prey. They frequently carry a rock in a pouch under their forearm and use this to smash open shells, making them one of the relatively small number of animals that use tools. They grow to in length and weigh . Although once near extinction, they have begun to spread again, from remnant populations in California and

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U ...

. Unlike most marine mammals (such as

seals Seals may refer to: * Pinniped, a diverse group of semi-aquatic marine mammals, many of which are commonly called seals, particularly: ** Earless seal, or "true seal" ** Fur seal * Seal (emblem), a device to impress an emblem, used as a means of a ...

or whales), sea otters do not have a layer of insulating blubber. As with other species of otter, they rely on a layer of air trapped in their fur, which they keep topped up by blowing into the fur from their mouths. They spend most of their time in the water, whereas other otters spend much of their time on land.

Giant otter

The giant otter (''Pteronura brasiliensis'') inhabits South America, especially the Amazon river basin, but is becoming increasingly rare due to poaching, habitat loss, and the use of mercury and other toxins in illegal alluvial gold mining. This gregarious animal grows to a length of up to , and is more aquatic than most other otters.

Relation with humans

Hunting

Otters have been hunted for their pelts from at least the 1700s, although it may have begun well before then. Early hunting methods included darts, arrows, nets and snares but later, traps were set on land and guns used. There has been a long history of otter pelts being worn around the world. In China it was standard for the royalty to wear robes made from them. People that were financially high in status also wore them. The tails of otters were often made into items for men to wear. These included hats and belts. Even some types of mittens for children have been made from the fur of otters. Otters have also been hunted using dogs, specifically the otterhound. From 1958 to 1963, the 11 otter hunts in England and Wales killed 1,065 otters between them. In such hunts, the hunters notched their poles after every kill. The prized trophy that hunters would take from the otters was the penis bone, which would be worn as a tie-pin.

Traffic Traffic comprises pedestrians, vehicles, ridden or herded animals, trains, and other conveyances that use public ways (roads) for travel and transportation. Traffic laws govern and regulate traffic, while rules of the road include traffic ...

(the wildlife trade monitoring network) reported that otters are at serious risk in Southeast Asia and have disappeared from parts of their former range. This decline in populations is due to hunting to supply the demand for skins.

Fishing for humans

For many generations, fishermen in southern Bangladesh have bred smooth-coated otters and used them to chase fish into their nets. Once a widespread practice, passed down from father to son throughout many communities in Asia, this traditional use of domesticated wild animals is still in practice in the district of Narail, Bangladesh.

Attacks on humans

Otters are territorial in nature. Certain regions, such as

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and ...

, have seen both otter and human populations expand during the first decade of the 21st century. A 2011 review by the IUCN/SSC Otter Specialist Group showed that otter attacks reported between 1875 and 2010 occurred most often in Florida, with the majority involving the North American otter. At least 42 instances of attack were found, including one resulting in death and another case of serious injury. Rabies was present in 36% of the anecdotal reports. 80% of otter bite victims do not end up obtaining medical treatment. Animal welfare groups say that unless threatened, otters rarely attack humans. In November 2021, a British man in his 60s was ambushed during his early morning walk in Singapore Botanic Gardens by about 20 otters. Despite weighing over 200 pounds, he was trampled and bitten and could not stand up without help from a nearby rescuer. The man speculated that another runner might have stepped on one of the animals earlier and wished that there could be more lighting installed at that location.

Religion and mythology

Norse mythology Norse, Nordic, or Scandinavian mythology is the body of myths belonging to the North Germanic peoples, stemming from Old Norse religion and continuing after the Christianization of Scandinavia, and into the Nordic folklore of the modern per ...

tells of the

dwarf Dwarf or dwarves may refer to: Common uses *Dwarf (folklore), a being from Germanic mythology and folklore * Dwarf, a person or animal with dwarfism Arts, entertainment, and media Fictional entities * Dwarf (''Dungeons & Dragons''), a humanoid ...

Ótr habitually taking the form of an otter. The myth of "Otter's Ransom" is the starting point of the Volsunga saga. In

Irish mythology Irish mythology is the body of myths native to the island of Ireland. It was originally oral tradition, passed down orally in the Prehistoric Ireland, prehistoric era, being part of ancient Celtic religion. Many myths were later Early Irish ...

, the character

Lí Ban Lí Ban (; thus 'paragon of women') may refer to an otherworldly female figure in Irish mythology. This Lí Ban claimed the beautiful Fand as sister, and was wife to Labraid Luathlám ar Claideb ("Labraid of the swift sword-hand"), the ruler of ...

was turned from a woman into a mermaid, half human and half salmon, and given three hundred years of life to roam the oceans. Her lapdog assumed the form of an otter and shared her prolonged lifetime and her extensive wanderings. In some Native American cultures, otters are considered totem animals. The otter is held to be a clean animal belonging to Ahura Mazda in

Zoroastrian Zoroastrianism is an Iranian religion and one of the world's oldest organized faiths, based on the teachings of the Iranian-speaking prophet Zoroaster. It has a dualistic cosmology of good and evil within the framework of a monotheisti ...

belief, and taboo to kill. In popular Korean mythology, it is told that people who see an otter (''soodal'') will attract 'rain clouds' for the rest of their lives. In the Buddhist Jataka tales, The Otters and The Wolf, two otters agreed to let a wolf settle their dispute in dividing their caught fish but it was taken away by the cunning wolf.

Japanese folklore

In Japanese, otters are called "kawauso" (). In Japanese folklore, they fool humans in the same way as foxes ( kitsune) and tanuki. In the Noto region, Ishikawa Prefecture, there are stories where they shapeshift into beautiful women or children wearing checker-patterned clothing. If a human attempts to speak to one, they will answer "oraya" and then answer "araya," and if anybody asks them anything, they say cryptic things like "kawai." There are darker stories, such as one from Kaga Province (now Ishikawa Prefecture) in which an otter that lives in the castle's moat shapeshifts into a woman, invites males, and then kills and eats them. In the kaidan, essays, and legends of the

Edo period The or is the period between 1603 and 1867 in the history of Japan, when Japan was under the rule of the Tokugawa shogunate and the country's 300 regional '' daimyo''. Emerging from the chaos of the Sengoku period, the Edo period was character ...

like the "Urami Kanawa" (), "Taihei Hyaku Monogatari" (), and the "Shifu Goroku" (), there are tales about strange occurrences like otters that shapeshift into beautiful women and kill men. In the town of Numatachi, Asa District, Hiroshima Prefecture (now

Hiroshima is the capital of Hiroshima Prefecture in Japan. , the city had an estimated population of 1,199,391. The gross domestic product (GDP) in Greater Hiroshima, Hiroshima Urban Employment Area, was US$61.3 billion as of 2010. Kazumi Matsui ...

), they are called "tomo no kawauso" () and "ato no kawauso" (). It is said that they shapeshift into bōzu (a kind of monk) and appear before passers-by, and if the passer-by tries to get close and look up, its height steadily increases until it becomes a large bōzu. In the Tsugaru region,

Aomori Prefecture is a prefecture of Japan in the Tōhoku region. The prefecture's capital, largest city, and namesake is the city of Aomori. Aomori is the northernmost prefecture on Japan's main island, Honshu, and is bordered by the Pacific Ocean to the eas ...

, they are said to possess humans. It is said that those possessed by otters lose their stamina as if their soul has been extracted. They are also said to shapeshift into severed heads and get caught in fishing nets. In the Kashima District and the Hakui District in Ishikawa Prefecture, they are seen as a yōkai under the name ''kabuso'' or ''kawaso''. They perform pranks like extinguishing the fire of the paper lanterns of people who walk on roads at night, shapeshifting into a beautiful woman of 18 or 19 years of age and fooling people, or tricking people and making them try to engage in sumo against a rock or a tree stump. It is said that they speak human words, and sometimes people are called and stopped while walking on roads. In the Ishikawa and Kochi Prefectures, they are said to be a type of kappa, and there are stories told about how they engage in sumo with otters. In places like the Hokuriku region, Kii, and Shikoku, the otters are seen as a type of kappa. In the Kagakushū, a dictionary from the

Muromachi period The is a division of Japanese history running from approximately 1336 to 1573. The period marks the governance of the Muromachi or Ashikaga shogunate (''Muromachi bakufu'' or ''Ashikaga bakufu''), which was officially established in 1338 by ...

, an otter that grew old becomes a kappa. In an Ainu folktale, in Urashibetsu (in Abashiri,

Hokkaido is Japan, Japan's Japanese archipelago, second largest island and comprises the largest and northernmost Prefectures of Japan, prefecture, making up its own List of regions of Japan, region. The Tsugaru Strait separates Hokkaidō from Honshu; th ...

), there are stories where monster otters shapeshift into humans, go into homes where there are beautiful girls, and try to kill the girl and make her its wife. In China, like in Japan, there are stories where otters shapeshift into beautiful women in old books like '' In Search of the Supernatural'' and the ''Zhenyizhi'' ().

References

External links

IUCN SSC Otter Specialist Group

ARKive
Photographs and videos of Eurasian otters. On the same site are photos and videos of the marine otter (''Lontra felina''), sea otter (''Enhydra lutris''), smooth-coated otter (''Lutrogale perspicillata'') and giant otter (''Pteronura brasiliensis'').
International Otter Survival Fund
{{Authority control Carnivorans of Europe Tool-using mammals Taxa named by Charles Lucien Bonaparte Semiaquatic animals