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44-426: Aonyx Enhydra Hydrictis Lontra Lutra Lutrogale Pteronura † Enhydriodon † Algarolutra † Cyrnaonyx † Megalenhydris † Sardolutra † Siamogale † Teruelictis † Satherium † Enhydritherium Otters are carnivorous mammals in the subfamily Lutrinae . The 13 extant otter species are all semiaquatic , aquatic , or marine . Lutrinae

88-499: 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. Norse mythology tells of the dwarf Ótr habitually taking

132-423: A combination of these two modes of propulsion, where the first third of their foot stroke generates propulsive drag and the last two-thirds of the stroke generates propulsive lift. The stroke of the foot through the water also generates vortices that aid propulsion. During the transition from drag-based to lift-based propulsion in ducks, leading edge vortices formed on the front of the foot are shed, which creates

176-585: A flow of water over the foot that likely aids lift production. Other species also create these vortices during their webbed foot stroke. Frogs also create vortices that shed off their feet when swimming in water. The vortices from the two feet do not interfere with each other; therefore, each foot is generating forward propulsion independently. Most fully aquatic vertebrates do not use paddling modes of locomotion, instead using undulatory modes of locomotion or flipper locomotion . Fully aquatic mammals and animals typically have flippers instead of webbed feet, which are

220-566: 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

264-870: A more heavily specialized and modified limb. It is hypothesized that an evolutionary transition between semiaquatic and fully aquatic higher vertebrates (especially mammals) involved both the specialization of swimming limbs and the transition to underwater, undulatory modes of motion. However, for semiaquatic animals that mainly swim at the surface, webbed feet are highly functional; they trade-off effectively between efficient terrestrial and aquatic locomotion . In addition, some waterfowl can also use paddling modes for underwater swimming, with added propulsion from flapping their wings. Diving ducks can swim underwater to forage. These ducks expend more than 90% of their energy to overcome their own buoyancy when they dive. They can also achieve higher speeds underwater due to surface speeds being limited to their hull speed ; at this speed,

308-541: A propulsive force. The interdigital membrane increases the surface area, which increases the propulsive drag the animal can generate with each stroke of its foot. This is a drag-based mode of propulsion. However, some waterfowl also utilize lift-based modes of propulsion, where their feet generate hydrodynamic lift due to the angle of attack of the foot and the relative water velocity. For example, great-crested grebes use solely lift-based propulsion due to their lateral foot stroke and asymmetric, lobated toes. Most waterfowl use

352-544: A selective advantage functionally. Webbed feet have arisen in all major vertebrate lineages with limbed animals. Most webbed-footed species spend part of their time in aquatic environments, indicating that this homologous structure provides some advantage to swimmers. Some examples from each class are highlighted here, but this is not a complete listing. Of the three orders of amphibians , Anura (frogs and toads) and Urodela (salamanders) have representative species with webbed feet. Frogs that live in aquatic environments, like

396-451: A selective advantage. In salamanders, webbed feet have arisen in multiple lineages, but in most do not contribute to increased function. However, in the cave salamander species Chiropterotriton magnipes (bigfoot splayfoot salamander), their webbed feet are morphologically unique from other salamanders and may serve a functional purpose. This demonstrates that webbed feet arise from developmental changes, but do not necessarily correlate with

440-468: A sub-group of reptiles, but they are a distinct class within vertebrates, so are discussed separately. Birds have a wide span of representatives with webbed feet, due to the diversity of waterfowl . Ducks , geese , and swans all have webbed feet. They utilize different foraging behaviors in water, but use similar modes of locomotion. There is a wide variety of webbing and lobation styles in bird feet, including birds with all digits joined in webbing, like

484-672: 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

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528-665: 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

572-480: Is a solution that has convergently evolved in many taxa, and is also used in aircraft to allow for high lift forces at high attack angles. This shape allows for the production of large forces during swimming through both drag-based and lift-based propulsion. Webbed feet are a compromise between aquatic and terrestrial locomotion. Aquatic control surfaces of non-piscine vertebrates may be paddles or hydrofoils . Paddles generate less lift than hydrofoils, and paddling

616-425: Is associated with drag-based control surfaces. The roughly triangular design of webbed feet, with a broad distal end, is specialized to increase propulsive efficiency by affecting a larger mass of water over generating increased lift. This is in contrast to a more hydrofoil-like flipper of many permanently aquatic animals. Webbed feet are the result of mutations in genes that normally cause interdigital tissue between

660-458: Is due to hunting to supply the demand for skins. 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. A 2011 review by

704-513: Is held to be a clean animal belonging to Ahura Mazda in Zoroastrian 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

748-474: 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

792-553: The Brandt's cormorant and birds with lobed digits, like grebes . Palmations and lobes enable swimming or help walking on loose ground such as mud . Penguins are notable for being the only birds (as well as animals in general) with both webbed feet and flippers (they have 2 each). The webbed or palmated feet of birds can be categorized into several types: The palmate foot is most common. Some semiaquatic mammals have webbed feet. Most of these have interdigital webbing , as opposed to

836-762: 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". 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 of otters are typically identified by their distinctive aroma,

880-444: 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

924-461: The syndactyly found in birds . Some notable examples include the platypus , the beaver , the otter , and the water opossum . Capybaras have slightly webbed feet, while hippopotamuses have webbed toes. In many species, webbed feet likely evolved to aid in generation of propulsion during swimming. Most webbed-footed animals utilize paddling modes of locomotion where their feet stroke backwards relative to their whole body motion, generating

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968-528: 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

1012-613: The Asian small-clawed otter in this genus, or in its own genus Amblonyx . They also differ as to whether the Congo clawless otter is a species, or is conspecific with the African clawless otter. [REDACTED] [REDACTED] [REDACTED] This article about a carnivoran is a stub . You can help Misplaced Pages by expanding it . Webbed foot It likely arose from mutations in developmental genes that normally cause tissue between

1056-789: 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. 80% of otter bite victims do not seek medical treatment. Animal welfare groups say that, unless threatened, otters rarely attack humans. In November 2021, about 20 otters ambushed

1100-495: The body out of the water. They can hydroplane, where they lift part of their body out of the water and paddle with their webbed feet to generate forces that allow them to overcome gravity; they also use paddle-assisted flying, where the whole body is lifted out of the water, and the wings and feet work in concert to generate lift forces. In extreme cases, this type of behavior is used for sexual selection . Western and Clark's grebes utilize their lobated feet to generate nearly 50% of

1144-690: The castle's moat shapeshifts into a woman, invites males, and then kills and eats them. Aonyx Aonyx is a genus of otters , containing three species , the African clawless otter , the Congo clawless otter , and the Asian small-clawed otter . The word aonyx means "clawless", derived from the prefix a- ("without") and onyx ("claw/hoof"). Three species are currently recognised: [REDACTED] [REDACTED] [REDACTED] Zoologists differ as to whether or not to include

1188-459: The common frog ( Rana temporaria ), have webbed feet. Salamanders in arboreal and cave environments also have webbed feet, but in most species, this morphological change does not likely have a functional advantage. Reptiles have webbed-footed representatives that include freshwater turtles and geckos . While turtles with webbed feet are aquatic, most geckos live in terrestrial and arboreal environments. Birds are typically classified as

1232-496: The course of evolutionary history. One pathway implicated in interdigital necrosis is the bone morphogenetic protein (BMP) signaling pathway . BMP signaling molecules (BMPs) are expressed in the tissue regions between digits during development. In experiments with chickens, mutations to a BMP receptor disrupted the apoptosis of interdigital tissue and caused webbed feet similar to ducks to develop. In ducks, BMPs are not expressed at all. These results indicate that in avian lineages,

1276-643: The cunning wolf. 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." There are darker stories, such as one from Kaga Province (now Ishikawa Prefecture ) in which an otter that lives in

1320-474: The digits to apoptose . These mutations were beneficial to many semiaquatic animals because the increased surface area from the webbing allowed for more swimming propulsion and swimming efficiency, especially in surface swimmers. The webbed foot also has enabled other novel behaviors like escape responses and mating behaviors. A webbed foot may also be called a paddle to contrast it from a more hydrofoil-like flipper . A webbed foot has connecting tissue between

1364-461: The disruption of BMP signaling in interdigital tissue caused webbed feet to arise. The magnitude of attenuation in this pathway is correlated with the amount of interdigital tissue preserved. Other genetic changes implicated in webbed feet development in avians include reduction of TGFβ -induced chondrogenesis and reduction of msx-1 and msx-2 gene expression. Webbed feet could also arise due to being linked to other morphological changes, without

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1408-487: The feet are a major location for heat loss. In birds, the legs utilize countercurrent heat exchange so that blood reaching the feet is already cooled by blood returning to the heart to minimize this effect. Webbed feet take on a variety of different shapes; in birds , the webbing can even be discontinuous, as seen in lobate-footed birds like grebes. However, one of the most common is the delta (Δ) or triangular shape seen in most waterfowl and frogs. This delta wing shape

1452-411: The force required to allow them to walk on water in elaborate sexual displays; they are likely the largest animal to "walk" on water, and are an order of magnitude heavier than the well-known lizards that exhibit a similar behavior. While webbed feet have mainly arisen in swimming species, they can also aid in terrestrial locomotors by increasing contact area on slick or soft surfaces. For P. rangei ,

1496-510: The form of an otter. The myth of "Otter's Ransom" 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 . The otter

1540-662: The fur of otters. Otters have also been hunted using dogs, especially 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 baculum , which would be worn as a tie-pin . 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

1584-400: 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

1628-498: The same genetic mutations can underlie different phenotypic expressions of syndactyly. While these conditions are disorders in humans, the variability in genetic cause of webbed digits informs our understanding of how this morphological change arose in species where webbed feet were selectively advantageous. These conditions also demonstrate a variety of genetic targets for mutation resulting in webbed feet, which may explain how this homologous structure could have arisen many times over

1672-492: The smell of which has been described as ranging from freshly mown hay to putrefied fish; these are known as spraints . 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

1716-726: 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 . 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

1760-399: The toes of the foot. Several distinct conditions can give rise to webbed feet, including interdigital webbing and syndactyly . The webbing can consist of membrane, skin, or other connective tissue and varies widely in different taxa. This modification significantly increases the surface area of the feet. One of the consequences of this modification in some species, specifically birds, is that

1804-520: The toes to apoptose . Apoptosis , or programmed cell death, in development is mediated by a variety of pathways, and normally causes the creation of digits by death of tissue separating the digits. Different vertebrate species with webbed feet have different mutations that disrupt this process, indicating that the structure arose independently in these lineages. In humans, syndactyly can arise from as many as nine unique subtypes with their own clinical, morphological, and genetic fingerprints. In addition,

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1848-1008: 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. Giant otter ( Pteronura brasiliensis ) North American river otter ( Lontra canadensis ) Marine otter ( Lontra felina ) Southern river otter ( Lontra provocax ) Neotropical otter ( Lontra longicaudis ) Sea otter ( Enhydra lutris ) Spotted-necked otter ( Hydrictis maculicollis ) Eurasian otter ( Lutra lutra ) Hairy-nosed otter ( Lutra sumatrana ) Japanese otter † ( Lutra nippon ) Lutra euxena † Lutra castiglionis † Lutra simplicidens † Lutra trinacriae † African clawless otter ( Aonyx capensis ) Asian small-clawed otter ( Aonyx cinerea ) Congo clawless otter ( Aonyx congicus ) Smooth-coated otter ( Lutrogale perspicillata ) Subfamily Lutrinae Otters have been hunted for their pelts from at least

1892-494: The wave drag increases to the point where the duck cannot swim faster. In ducks, webbed feet have also enabled extreme forms of propulsion that are used for escape behaviors and courtship display . Surface swimmers are speed-limited due to increasing drag as they approach a physically defined hull speed , which is determined by their body length. In order to achieve speeds higher than hull speed, some ducks, like eider ducks, use distinctive modes of locomotion that involve lifting

1936-528: 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 sliding on them into

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