Otter Temporal range: Middle Miocene to present [1] | |
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Eurasian otter (Lutra lutra) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Carnivora |
Family: | Mustelidae |
Subfamily: | Lutrinae Bonaparte, 1838 |
Type genus | |
Lutra Brünnich, 1771 | |
Genera | |
Aonyx Contents |
Otters are carnivorous mammals in the subfamily Lutrinae. The 13 extant otter species are all semiaquatic, aquatic, or marine. Lutrinae is a branch of the Mustelidae family, which includes weasels, badgers, mink, and wolverines, among other animals.
Otters' habitats include dens known as holts or couches, with their social structure described by terms such as dogs or boars for males, bitches or sows for females, and pups or cubs for offspring. Groups of otters can be referred to as a bevy, family, lodge, romp, or raft when in water, indicating their social and playful characteristics. Otters are known for their distinct feces, termed spraints, which can vary in smell from freshly mown hay to putrefied fish.
Otters exhibit a varied life cycle with a gestation period of about 60–86 days, and offspring typically stay with their family for a year. They can live up to 16 years, with their diet mainly consisting of fish and sometimes frogs, birds, or shellfish, depending on the species. Otters are distinguished by their long, slim bodies, powerful webbed feet for swimming, and their dense fur, which keeps them warm and buoyant in water. They are playful animals, engaging in activities like sliding into water on natural slides and playing with stones.
There are 13 known species of otters, ranging in size and habitat preferences, with some species adapted to cold waters requiring a high metabolic rate for warmth. Otter-human interactions have varied over time, with otters being hunted for their pelts, used in fishing practices in southern Bangladesh, and occasionally attacking humans, though such incidents are rare and often a result of provocation. Otters hold a place in various cultures' mythology and religion, symbolizing different attributes and stories, from Norse mythology to Native American totems and Asian folklore, where they are sometimes believed to possess shapeshifting abilities.
The word otter derives from the Old English word otor or oter. This and cognate words in other Indo-European languages ultimately stem from the Proto-Indo-European root *wódr̥, which also gave rise to the English word "water". [4] [5]
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. [6] [7] The collective nouns for otters are bevy, family, lodge, romp (being descriptive of their often playful nature), or, when in water, raft. [8] [9]
The feces 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; [10] these are known as spraints. [11]
The gestation period in otters is about 60 to 86 days. The newborn pup is cared for by the bitch, dog, and older offspring. Female 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.
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 for 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 0.6 to 1.8 m (2.0 to 5.9 ft) in length and 1 to 45 kg (2.2 to 99.2 lb) in weight. The Asian small-clawed otter is the smallest otter species and the giant otter and sea otter 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 rates to help keep them warm. Eurasian otters must eat 15% of their body weight each day, and sea otters 20 to 25%, depending on the temperature. In water as warm as 10 °C (50 °F), an otter needs to catch 100 g (3.5 oz) of fish per hour to survive. Most species hunt for three to five hours each day and nursing mothers up to eight hours each day.
For most otters, fish is the staple of their diet. This is often supplemented by frogs, crayfish and crabs. [12] 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, sea urchins and other shelled creatures. They are notable for their ability to use stones to break open shellfish on their bellies. This skill must be learned by the young. [13]
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 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.
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Image | Genus | Species |
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Lutra Brisson, 1762 |
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Hydrictis Pocock, 1921 |
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Lutrogale (Gray, 1865) |
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Lontra Gray, 1843 |
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Pteronura Gray, 1837 |
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Aonyx Lesson, 1827 |
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Enhydra Fleming, 1828 |
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Subfamily Lutrinae
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. [26]
Otters have also been hunted using dogs, especially the otterhound. [27] 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 baculum, which would be worn as a tie-pin. [28]
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. [29]
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. [30] [31]
A 2011 review by the IUCN/SSC Otter Specialist Group showed that otter attacks reported between 1875 and 2010 occurred most often in Florida, where human and otter populations have substantially increased since 2000, 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. Attacking otters had rabies in 36% of anecdotal reports. [32] 80% of otter bite victims do not seek medical treatment. [33]
Animal welfare groups say that, unless threatened, otters rarely attack humans. [34] In November 2021, about 20 otters ambushed a British man in his 60s during an early morning walk in Singapore Botanic Gardens. 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. [34]
Norse mythology tells of the dwarf Ótr habitually taking the form of an otter. The myth of "Otter's Ransom" [35] is the starting point of the Volsunga saga.
In Irish mythology, the character Lí Ban 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. [36]
The otter is held to be a clean animal belonging to Ahura Mazda in Zoroastrian belief, and taboo to kill. [37]
In popular Korean mythology, it is told that people who see an otter (soodal) will attract 'rain clouds' for the rest of their lives. [38]
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. [39]
In Japanese, otters are called "kawauso" (獺、川獺). 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." [40] [41] 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. [42]
In the kaidan, essays, and legends of the Edo period like the "Urami Kanawa" (裏見寒話), [43] "Taihei Hyaku Monogatari" (太平百物語), and the "Shifu Goroku" (四不語録), there are tales about strange occurrences like otters that shapeshift into beautiful women and kill men. [41]
In the town of Numatachi, Asa District, Hiroshima Prefecture (now Hiroshima), they are called "tomo no kawauso" (伴のカワウソ) and "ato no kawauso" (阿戸のカワウソ). 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. [44]
In the Tsugaru region, Aomori Prefecture, they are said to possess humans. It is said that those possessed by otters lose their stamina as if their soul has been extracted. [45] They are also said to shapeshift into severed heads and get caught in fishing nets. [45]
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. [41] It is said that they speak human words, and sometimes people are called and stopped while walking on roads. [46]
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. [41] In places like the Hokuriku region, Kii, and Shikoku, the otters are seen as a type of kappa. [47] In the Kagakushū, a dictionary from the Muromachi period, an otter that grew old becomes a kappa. [48]
In an Ainu folktale, in Urashibetsu (in Abashiri, Hokkaido), 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. [49]
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 (甄異志). [43]
The Mustelidae are a diverse family of carnivoran mammals, including weasels, badgers, otters, polecats, martens, grisons, and wolverines. Otherwise known as mustelids, they form the largest family in the suborder Caniformia of the order Carnivora with about 66 to 70 species in nine subfamilies.
The sea otter is a marine mammal native to the coasts of the northern and eastern North Pacific Ocean. Adult sea otters typically weigh between 14 and 45 kg, making them the heaviest members of the weasel family, but among the smallest marine mammals. Unlike most marine mammals, the sea otter's primary form of insulation is an exceptionally thick coat of fur, the densest in the animal kingdom. Although it can walk on land, the sea otter is capable of living exclusively in the ocean.
The Asian small-clawed otter, also known as the oriental small-clawed otter and the small-clawed otter, is an otter species native to South and Southeast Asia. It has short claws that do not extend beyond the pads of its webbed digits. With a total body length of 730 to 960 mm, and a maximum weight of 5 kg (11 lb), it is the smallest otter species in the world.
Lontra is a genus of otters from the Americas.
The North American river otter, also known as the northern river otter and river otter, is a semiaquatic mammal that lives only on the North American continent throughout most of Canada, along the coasts of the United States and its inland waterways. An adult North American river otter can weigh between 5.0 and 14 kg. The river otter is protected and insulated by a thick, water-repellent coat of fur.
Lutra is a genus of otters, one of seven in the subfamily Lutrinae.
Ekorus ekakeran is a large, extinct mustelid mammal. Fossils, including largely complete skeletons, are known from the late Miocene of Kenya.
The giant otter or giant river otter is a South American carnivorous mammal. It is the longest member of the weasel family, Mustelidae, a globally successful group of predators, reaching up to 1.8 m. Atypical of mustelids, the giant otter is a social species, with family groups typically supporting three to eight members. The groups are centered on a dominant breeding pair and are extremely cohesive and cooperative. Although generally peaceful, the species is territorial, and aggression has been observed between groups. The giant otter is diurnal, being active exclusively during daylight hours. It is the noisiest otter species, and distinct vocalizations have been documented that indicate alarm, aggression, and reassurance.
The neotropical otter or neotropical river otter is a near-threatened otter species found in freshwater systems from Mexico and Central America through mainland South America, as well as the island of Trinidad. It is physically similar to the northern and southern river otter, which occur directly north and south of this species' range, respectively. Its head-to-body length can range from 36–66 centimetres (14–26 in), plus a tail of 37–84 centimetres (15–33 in). Body weight ranges from 5–15 kilograms (11–33 lb).
The marine otter is a rare and relatively unknown South American mammal of the weasel family (Mustelidae). The scientific name means "feline otter", and in Spanish, the marine otter is also often referred to as gato marino: "marine cat". The marine otter only lives in saltwater, coastal environments and rarely ventures into fresh water or estuarine habitats. This saltwater exclusivity is unlike most other otter species, except for the almost fully aquatic sea otter of the North Pacific.
Lutrogale was proposed as generic name by John Edward Gray in 1865 for otters with a convex forehead and nose, using the smooth-coated otter L. perspicillata as type species.
The smooth-coated otter is a freshwater otter species from regions of South and Southwest Asia, with the majority of its numbers found in Southeast Asia. It has been ranked as "vulnerable" on the IUCN Red List since 1996, as it is threatened by habitat loss, pollution of wetlands and poaching for the illegal wildlife trade. As the common name indicates, its fur is relatively smooth, and somewhat shorter in length than that of other otter species.
Cyrnaonyx is an extinct genus of Lutrinae, otters from the Pleistocene. It was originally described by Helbing based on materials from France and he also attributed material from Corsica to it. The latter appeared to belong to another species and genus, Algarolutra majori. The only species of Cyrnaonyx is C. antiqua. It is known from the Pleistocene of Europe: France, Germany, Netherlands, Southern England and probably Italy.
Megalenhydris barbaricina is an extinct species of giant otter from the Late Pleistocene of Sardinia. It is known from a single partial skeleton, discovered in the Grotta di Ispinigoli near Dorgali, and was described in 1987. It was larger than any living otter, exceeding the size of South American giant otters (Petrolutra), which can reach two meters in length. The species is one of four extinct otter species from Sardinia and Corsica. The others are Algarolutra majori, Lutra castiglionis and Sardolutra ichnusae. It is suggested to have ultimately originated from the much smaller European mainland species "Lutra" simplicidens, which may be more closely related to Lutrogale than to modern Lutra species. The structure of the teeth points to a diet of bottom dwelling fish and crustaceans. A special characteristic of the species is the flattening of the first few caudal vertebrae. This might point to a slightly flattened tail.
The Shungura Formation is a stratigraphic formation located in the Omo river basin in Ethiopia. It dates to the Late Pliocene to Early Pleistocene. Oldowan tools have been found in the formation, suggesting early use of stone tools by hominins. Among many others, fossils of Panthera were found in Member G of the formation.
Enhydriodon is an extinct genus of mustelids known from Africa, Pakistan, and India that lived from the late Miocene to the early Pleistocene. It contains nine confirmed species, two debated species, and at least a few other undescribed species from Africa. The genus belongs to the tribe Enhydriodontini in the otter subfamily Lutrinae. Enhydriodon means "otter tooth" in Ancient Greek and is a reference to its dentition rather than to the Enhydra genus, which includes the modern sea otter and its two prehistoric relatives.
Siamogale is an extinct genus of giant otter from the late Miocene-early Pliocene of eastern Asia. Three species are currently known, S. thailandica and S. bounosa from Thailand and S. melilutra from China.
Lontra weiri is a fossil species in the carnivoran family Mustelidae from the Hagerman Fossil Beds of Idaho. It shared its habitat with Satherium piscinarium, a probable ancestor of the giant otter of South America. It is named in honor of musician Bob Weir, and is the oldest known member of its genus. Prior to its discovery, Lontra was thought to have evolved from Lutra licenti, which dates from the Pleistocene of East Asia.
Lutra castiglionis, the Castiglione otter or Corsican otter, is an extinct species of otter that was endemic to Corsica during the Pleistocene.
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