89-470: Enhydra lutris - Sea otter † Enhydra macrodonta † 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 from other otters during the Pliocene , approximately 5 mya. They probably arose from
178-488: A blubber layer, while their oil glands help matt down their fur and keep it from holding air. Thick bones also prove crucial in increasing buoyancy, as sea otters spend long hours floating atop the ocean. In a study, southern and northern Sea Otter populations were compared against the African clawless otter , and it was determined that aquatic traits like loss of smell and hair thickness independently evolved, evidencing
267-404: A metabolic rate two or three times that of comparatively sized terrestrial mammals. It must eat an estimated 25 to 38% of its own body weight in food each day to burn the calories necessary to counteract the loss of heat due to the cold water environment. Its digestive efficiency is estimated at 80 to 85%, and food is digested and passed in as little as three hours. Most of its need for water
356-511: 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
445-505: 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
534-571: A complex genome of polygenic traits resulting in complex systems. This study was only able to take place after sequencing of Sea Otter nuclear genomes and through phylogeny to find a close ancestor with which to compare genomes. Previously, it was suspected that sea otters came from the same evolutionary branch as earless seals , such as harbor and monk seals . Sea Otters have experienced numerous population bottlenecks throughout their history, with significant numbers being wiped out 9,000-10,000 generations ago and 300–700 generations ago, long before
623-421: A distinct molting season. As the ability of the guard hairs to repel water depends on utmost cleanliness, the sea otter has the ability to reach and groom the fur on any part of its body, taking advantage of its loose skin and an unusually supple skeleton . The coloration of the pelage is usually deep brown with silver-gray speckles, but it can range from yellowish or grayish brown to almost black. In adults,
712-566: 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
801-561: A home range a few kilometres long, and remain there year-round. The sea otter population is thought to have once been 150,000 to 300,000, stretching in an arc across the North Pacific from northern Japan to the central Baja California Peninsula in Mexico. The fur trade that began in the 1740s reduced the sea otter's numbers to an estimated 1,000 to 2,000 members in 13 colonies. Hunting records researched by historian Adele Ogden place
890-583: A male sea otter took up residence at Simpson Reef off of Cape Arago for six months. This male is thought to have originated from a colony in Washington, but disappeared after a coastal storm. On 18 February 2009, a male sea otter was spotted in Depoe Bay off the Oregon Coast . It could have traveled to the state from either California or Washington. The historic population of California sea otters
979-612: A mate. The species exhibits a variety of vocal behaviors. The cry of a pup is often compared to that of a gull . Females coo when they are apparently content; males may grunt instead. Distressed or frightened adults may whistle, hiss, or in extreme circumstances, scream. Although sea otters can be playful and sociable, they are not considered to be truly social animals . They spend much time alone, and each adult can meet its own hunting, grooming, and defense needs. Sea otters are polygynous : males have multiple female partners, typically those that inhabit their territory. If no territory
SECTION 10
#17327919577791068-513: A mother may be forced to abandon a pup if she cannot find enough food for it; at the other extreme, a pup may be nursed until it is almost adult size. Pup mortality is high, particularly during an individual's first winter – by one estimate, only 25% of pups survive their first year. Pups born to experienced mothers have the highest survival rates. Females perform all tasks of feeding and raising offspring, and have occasionally been observed caring for orphaned pups. Much has been written about
1157-573: 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
1246-459: A separate colony was discovered in the central British Columbia coast. It is not known if this colony, which numbered about 300 animals in 2004, was founded by transplanted otters or was a remnant population that had gone undetected. By 2013, this population exceeded 1,100 individuals, was increasing at an estimated 12.6% annual rate, and its range included Aristazabal Island , and Milbanke Sound south to Calvert Island . In 2008, Canada determined
1335-465: 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
1424-543: Is established, they seek out females in estrus. When a male sea otter finds a receptive female, the two engage in playful and sometimes aggressive behavior. They bond for the duration of estrus, or 3 days. The male holds the female's head or nose with his jaws during copulation. Visible scars are often present on females from this behavior. Births occur year-round, with peaks between May and June in northern populations and between January and March in southern populations. Gestation appears to vary from four to twelve months, as
1513-412: Is fairly short, thick, slightly flattened, and muscular. The front paws are short with retractable claws, with tough pads on the palms that enable gripping slippery prey. The bones show osteosclerosis , increasing their density to reduce buoyancy. The sea otter presents an insight into the evolutionary process of the mammalian invasion of the aquatic environment , which has occurred numerous times over
1602-419: Is found from Alaska's Aleutian Islands to Oregon and E. l. nereis , the southern sea otter , is native to central and southern California. The Asian sea otter is the largest subspecies and has a slightly wider skull and shorter nasal bones than both other subspecies. Northern sea otters possess longer mandibles (lower jaws) while southern sea otters have longer rostrums and smaller teeth. The sea otter
1691-528: 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
1780-402: Is met through food, although, in contrast to most other marine mammals, it also drinks seawater. Its relatively large kidneys enable it to derive fresh water from sea water and excrete concentrated urine. The sea otter is diurnal . It has a period of foraging and eating in the morning, starting about an hour before sunrise, then rests or sleeps in mid-day. Foraging resumes for a few hours in
1869-600: Is most likely to mate if he maintains a breeding territory in an area that is also favored by females. As autumn is the peak breeding season in most areas, males typically defend their territory only from spring to autumn. During this time, males patrol the boundaries of their territories to exclude other males, although actual fighting is rare. Adult females move freely between male territories, where they outnumber adult males by an average of five to one. Males that do not have territories tend to congregate in large, male-only groups, and swim through female areas when searching for
SECTION 20
#17327919577791958-426: Is neither particularly acute nor poor. An adult's 32 teeth , particularly the molars , are flattened and rounded for crushing rather than cutting food. Seals and sea otters are the only carnivores with two pairs of lower incisor teeth rather than three; the adult dental formula is 3.1.3.1 2.1.3.2 . The teeth and bones are sometimes stained purple as a result of ingesting sea urchins. The sea otter has
2047-634: Is not known, although orca predation is suspected. The sea otter population in Prince William Sound was also hit hard by the Exxon Valdez oil spill , which killed thousands of sea otters in 1989. In 1969 and 1970, 59 sea otters were translocated from Amchitka Island to Washington , and released near La Push and Point Grenville . The translocated population is estimated to have declined to between 10 and 43 individuals before increasing, reaching 208 individuals in 1989. As of 2017,
2136-617: Is one of the smallest marine mammal species, but it is the heaviest mustelid. Male sea otters usually weigh 22 to 45 kg (49 to 99 lb) and are 1.2 to 1.5 m (3 ft 11 in to 4 ft 11 in) in length, though specimens up to 54 kg (119 lb) have been recorded. Females are smaller, weighing 14 to 33 kg (31 to 73 lb) and measuring 1.0 to 1.4 m (3 ft 3 in to 4 ft 7 in) in length. The average weight for adult sea otters that are in more densely populated areas, at 28.3 kg (62 lb) in males and 21.1 kg (47 lb) in females,
2225-450: Is the only marine animal capable of lifting and turning over rocks, which it often does with its front paws when searching for prey. The sea otter may also pluck snails and other organisms from kelp and dig deep into underwater mud for clams . It is the only marine mammal that catches fish with its forepaws rather than with its teeth. A Misplaced Pages editor has observed Otters pulling clusters of gooseneck barnacles and mussels from piers at
2314-419: Is unique among the mustelids in not making dens or burrows , in having no functional anal scent glands , and in being able to live its entire life without leaving the water. The only living member of the genus Enhydra , the sea otter is so different from other mustelid species that, as recently as 1982, some scientists believed it was more closely related to the earless seals . Genetic analysis indicates
2403-559: The Aleutian Chain ". "Yezo" refers to the island province of Hokkaido , in northern Japan, where the country's only confirmed population of western sea otter resides. Sightings have been documented in the waters of Cape Nosappu , Erimo , Hamanaka and Nemuro , among other locations in the region. Currently, the most stable and secure part of the western sea otter's range is along the Russian Far East coastline, in
2492-495: The Aleutian Islands and California have recently declined or have plateaued at depressed levels. For these reasons, the sea otter remains classified as an endangered species . The sea otter is the heaviest (the giant otter is longer, but significantly slimmer) member of the family Mustelidae , a diverse group that includes the 13 otter species and terrestrial animals such as weasels , badgers , and minks . It
2581-788: 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,
2670-655: The Russian-American Company snuck Aleuts into San Francisco Bay multiple times, despite the Spanish capturing or shooting them while hunting sea otters in the estuaries of San Jose , San Mateo , San Bruno and around Angel Island . The founder of Fort Ross , Ivan Kuskov , finding otters scarce on his second voyage to Bodega Bay in 1812, sent a party of Aleuts to San Francisco Bay, where they met another Russian party and an American party, and caught 1,160 sea otters in three months. By 1817, sea otters in
2759-444: 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
Enhydra - Misplaced Pages Continue
2848-536: 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
2937-528: 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
3026-817: 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
3115-535: The Kurils, 2,000 to 3,500 at Kamchatka and another 5,000 to 5,500 at the Commander Islands. Growth has slowed slightly, suggesting the numbers are reaching carrying capacity . Along the North American coast south of Alaska, the sea otter's range is discontinuous. A remnant population survived off Vancouver Island into the 20th century, but it died out despite the 1911 international protection treaty, with
3204-600: The Russian east coast, Alaska, British Columbia, Washington, and California, with reports of recolonizations in Mexico and Japan. Population estimates made between 2004 and 2007 give a worldwide total of approximately 107,000 sea otters. Adele Ogden wrote in The California Sea Otter Trade that western sea otter were hunted "from Yezo northeastward past the Kuril Group and Kamchatka to
3293-628: The abalone shell using a large stone, with observed rates of 45 blows in 15 seconds. Releasing an abalone, which can cling to rock with a force equal to 4,000 times its own body weight, requires multiple dives. Although each adult and independent juvenile forages alone, sea otters tend to rest together in single-sex groups called rafts . A raft typically contains 10 to 100 animals, with male rafts being larger than female ones. The largest raft ever seen contained over 2000 sea otters. To keep themselves from drifting out to sea when resting and eating, sea otters may wrap themselves in kelp . A male sea otter
3382-452: The afternoon and subsides before sunset, and a third foraging period may occur around midnight. Females with pups appear to be more inclined to feed at night. Observations of the amount of time a sea otter must spend each day foraging range from 24 to 60%, apparently depending on the availability of food in the area. Sea otters spend much of their time grooming, which consists of cleaning the fur, untangling knots, removing loose fur, rubbing
3471-665: The area were practically eliminated and the Russians sought permission from the Spanish and the Mexican governments to hunt further and further south of San Francisco. In 1833, fur trappers George Nidever and George Yount canoed "along the Petaluma side of [the] Bay, and then proceeded to the San Joaquin River ", returning with sea otter, beaver, and river otter pelts. Remnant sea otter populations may have survived in
3560-406: The base. Unlike most other marine mammals, the sea otter has no blubber and relies on its exceptionally thick fur to keep warm. With up to 150,000 strands of hair per square centimetre (970,000/in ), its fur is the densest of any animal. The fur consists of long, waterproof guard hairs and short underfur; the guard hairs keep the dense underfur layer dry. There is an air compartment between
3649-720: The bay until 1840, when the Rancho Punta de Quentin was granted to Captain John B. R. Cooper , a sea captain from Boston, by Mexican Governor Juan Bautista Alvarado along with a license to hunt sea otters, reportedly then prevalent at the mouth of Corte Madera Creek . Otter Aonyx Enhydra Hydrictis Lontra Lutra Lutrogale Pteronura † Enhydriodon † Algarolutra † Cyrnaonyx † Megalenhydris † Sardolutra † Siamogale † Teruelictis † Satherium † Enhydritherium Otters are carnivorous mammals in
Enhydra - Misplaced Pages Continue
3738-439: The chance of deleterious genetic drift . Pteronura (giant otter) Lontra (4 species) Enhydra (sea otter) Hydrictis (spotted-necked otter) Lutra (2 species) Aonyx (African clawless) Amblonyx (Asian small-clawed) Lutrogale (smooth-coated) The first scientific description of the sea otter is contained in the field notes of Georg Steller from 1751, and
3827-583: The closely related Enhydritherium , a bunodont otter endemic to North America during the late Miocene and early Pliocene epochs. Enhydra reevei , the oldest known species, has its origins in the Atlantic, suggesting this may have been where sea otters originated. Fossil evidence indicates the Enhydra lineage became isolated in the North Pacific approximately 2 million years ago, giving rise to
3916-419: The course of mammalian evolution. Having only returned to the sea about 3 million years ago, sea otters represent a snapshot at the earliest point of the transition from fur to blubber. In sea otters, fur is still advantageous, given their small nature and division of lifetime between the aquatic and terrestrial environments. However, as sea otters evolve and adapt to spending more and more of their lifetimes in
4005-650: 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
4094-437: The evolution of numerous traits to create hallmark features like thick and oily fur and large bones, compared to their freshwater sister species. Sea otters require these traits to survive the cold waters of the northern Pacific Ocean , in which they spend their entire lives despite occasionally coming out of the water as pups. Sea otters have the thickest fur of any animal (~1,000,000 hairs per square inch), as they do not have
4183-505: The evolutionary future of sea otters. The sea otter propels itself underwater by moving the rear end of its body, including its tail and hind feet, up and down, and is capable of speeds of up to 9 kilometres per hour (5.6 mph). When underwater, its body is long and streamlined, with the short forelimbs pressed closely against the chest. When at the surface, it usually floats on its back and moves by sculling its feet and tail from side to side. At rest, all four limbs can be folded onto
4272-534: The eyes are open, ten teeth are visible, and the pup has a thick coat of baby fur. Mothers have been observed to lick and fluff a newborn for hours; after grooming, the pup's fur retains so much air, the pup floats like a cork and cannot dive. The fluffy baby fur is replaced by adult fur after about 13 weeks. Nursing lasts six to eight months in Californian populations and four to twelve months in Alaska, with
4361-461: The few mammal species to use tools. In most of its range, it is a keystone species , controlling sea urchin populations which would otherwise inflict extensive damage to kelp forest ecosystems . Its diet includes prey species that are also valued by humans as food, leading to conflicts between sea otters and fisheries. Sea otters, whose numbers were once estimated at 150,000–300,000, were hunted extensively for their fur between 1741 and 1911, and
4450-517: 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
4539-677: 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
SECTION 50
#17327919577794628-515: The fur to squeeze out water and introduce air, and blowing air into the fur. To casual observers, it appears as if the animals are scratching, but they are not known to have lice or other parasites in the fur. When eating, sea otters roll in the water frequently, apparently to wash food scraps from their fur. The sea otter hunts in short dives, often to the sea floor . Although it can hold its breath for up to five minutes, its dives typically last about one minute and not more than four minutes. It
4717-444: The fur trade. These previous genetic bottlenecks are responsible for already low genetic diversity amongst species members, making the secondary bottleneck caused by the fur trade more significant. These primary bottlenecks were most likely caused by disease, a common cause for genetic bottlenecks. Estimates place these bottlenecks at leaving around ten to forty animals for about eight to forty-four years. This led to genetic drift , as
4806-431: The head, throat, and chest are lighter in color than the rest of the body. The sea otter displays numerous adaptations to its marine environment. The nostrils and small ears can close. The hind feet, which provide most of its propulsion in swimming, are long, broadly flattened, and fully webbed . The fifth digit on each hind foot is longest, facilitating swimming while on its back, but making walking difficult. The tail
4895-685: 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 sea otter inhabits nearshore environments, where it dives to the sea floor to forage . It preys mostly on marine invertebrates such as sea urchins , various mollusks and crustaceans , and some species of fish . Its foraging and eating habits are noteworthy in several respects. Its use of rocks to dislodge prey and to open shells makes it one of
4984-594: The last sea otter taken near Kyuquot in 1929. From 1969 to 1972, 89 sea otters were flown or shipped from Alaska to the west coast of Vancouver Island. This population increased to over 5,600 in 2013 with an estimated annual growth rate of 7.2%, and their range on the island's west coast extended north to Cape Scott and across the Queen Charlotte Strait to the Broughton Archipelago and south to Clayoquot Sound and Tofino . In 1989,
5073-440: The level of devotion of sea otter mothers for their pups – a mother gives her infant almost constant attention, cradling it on her chest away from the cold water and attentively grooming its fur. When foraging, she leaves her pup floating on the water, sometimes wrapped in kelp to keep it from floating away; if the pup is not sleeping, it cries loudly until she returns. Mothers have been known to carry their pups for days after
5162-462: The meat in shellfish. To eat large sea urchins, which are mostly covered with spines, the sea otter bites through the underside where the spines are shortest, and licks the soft contents out of the urchin's shell. The sea otter's use of rocks when hunting and feeding makes it one of the few mammal species to use tools. To open hard shells, it may pound its prey with both paws against a rock on its chest. To pry an abalone off its rock, it hammers
5251-529: The modern sea otter, Enhydra lutris . One related species has been described, Enhydra reevei , from the Pleistocene of East Anglia . The modern sea otter evolved initially in northern Hokkaidō and Russia, and then spread east to the Aleutian Islands , mainland Alaska , and down the North American coast. In comparison to cetaceans , sirenians , and pinnipeds , which entered the water approximately 50, 40, and 20 million years ago, respectively,
5340-525: The mother beginning to offer bits of prey at one to two months. The milk from a sea otter's two abdominal nipples is rich in fat and more similar to the milk of other marine mammals than to that of other mustelids . A pup, with guidance from its mother, practices swimming and diving for several weeks before it is able to reach the sea floor. Initially, the objects it retrieves are of little food value, such as brightly colored starfish and pebbles. Juveniles are typically independent at six to eight months, but
5429-859: The northwestern Pacific waters off of the country (namely Kamchatka and Sakhalin Island ), occasionally being seen in and around the Sea of Okhotsk . Before the 19th century, around 20,000 to 25,000 sea otters lived near the Kuril Islands , with more near Kamchatka and the Commander Islands . After the years of the Great Hunt, the population in these areas, currently part of Russia, was only 750. By 2004, sea otters had repopulated all of their former habitat in these areas, with an estimated total population of about 27,000. Of these, about 19,000 are at
SECTION 60
#17327919577795518-467: The now-extinct Enhydra macrodonta and the modern sea otter. [REDACTED] [REDACTED] [REDACTED] This article about a carnivoran is a stub . You can help Misplaced Pages by expanding it . Enhydra lutris 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 14 and 45 kg (30 and 100 lb), making them
5607-695: The population was estimated at over 2,000 individuals, and their range extends from Point Grenville in the south to Cape Flattery in the north and east to Pillar Point along the Strait of Juan de Fuca . In Washington, sea otters are found almost exclusively on the outer coasts. They can swim as close as six feet off shore along the Olympic coast. Reported sightings of sea otters in the San Juan Islands and Puget Sound almost always turn out to be North American river otters , which are commonly seen along
5696-466: The populations of northern and southern sea otters were cut off from one another by thousands of miles, leading to significant genomic differences. However, the modern population bottleneck caused by the fur trade of the eighteenth and early twentieth centuries presents the most significant concern to scientists and conservationists attempting to recover population numbers and genetic diversity. Each bottleneck has lowered genomic diversity and thus increased
5785-400: 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
5874-449: The pups' deaths. Females become sexually mature at around three or four years of age and males at around five; however, males often do not successfully breed until a few years later. A captive male sired offspring at age 19. In the wild, sea otters live to a maximum age of 23 years, with lifespans ranging from 10 to 15 years for males and 15–20 years for females. Several captive individuals have lived past 20 years. The Seattle Aquarium
5963-478: The sea otter and its closest extant relatives, which include the African speckle-throated otter , Eurasian otter , African clawless otter and Asian small-clawed otter , shared an ancestor approximately 5 million years ago. Fossil evidence indicates the Enhydra lineage became isolated in the North Pacific approximately 2 million years ago, giving rise to the now-extinct Enhydra macrodonta and
6052-432: The sea otter find prey by touch when waters are dark or murky. Researchers have noted when they approach in plain view, sea otters react more rapidly when the wind is blowing towards the animals, indicating the sense of smell is more important than sight as a warning sense. Other observations indicate the sea otter's sense of sight is useful above and below the water, although not as good as that of seals. Its hearing
6141-548: The sea otter is a relative newcomer to a marine existence. In some respects, though, the sea otter is more fully adapted to water than pinnipeds, which must haul out on land or ice to give birth. The full genome of the northern sea otter ( Enhydra lutris kenyoni ) was sequenced in 2017 and may allow for examination of the sea otter's evolutionary divergence from terrestrial mustelids. Following their divergence from their most common ancestor five million years ago, sea otters have developed traits dependent on polygenic selection, or
6230-502: The sea, the convergent evolution of blubber suggests that the reliance on fur for insulation would be replaced by a dependency on blubber. This is particularly true due to the diving nature of the sea otter; as dives become lengthier and deeper, the air layer's ability to retain heat or buoyancy decreases, while blubber remains efficient at both of those functions. Blubber can also additionally serve as an energy source for deep dives, which would most likely prove advantageous over fur in
6319-536: The seashore. However, biologists have confirmed isolated sightings of sea otters in these areas since the mid-1990s. The last native sea otter in Oregon was probably shot and killed in 1906. In 1970 and 1971, a total of 95 sea otters were transplanted from Amchitka Island , Alaska to the Southern Oregon coast. However, this translocation effort failed and otters soon again disappeared from the state. In 2004,
6408-471: The shore. They are found most often in areas with protection from the most severe ocean winds, such as rocky coastlines, thick kelp forests , and barrier reefs . Although they are most strongly associated with rocky substrates , sea otters can also live in areas where the sea floor consists primarily of mud, sand, or silt. Their northern range is limited by ice, as sea otters can survive amidst drift ice but not land-fast ice . Individuals generally occupy
6497-400: 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
6586-415: The species is capable of delayed implantation followed by four months of pregnancy. In California, sea otters usually breed every year, about twice as often as those in Alaska. Birth usually takes place in the water and typically produces a single pup weighing 1.4 to 2.3 kilograms (3 lb 1 oz to 5 lb 1 oz). Twins occur in 2% of births; however, usually only one pup survives. At birth,
6675-513: The species was described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae . Originally named Lutra marina , it underwent numerous name changes before being accepted as Enhydra lutris in 1922. The generic name Enhydra , derives from the Ancient Greek en /εν "in" and hydra /ύδρα "water", meaning "in the water", and the Latin word lutris , meaning "otter". It
6764-415: 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
6853-408: The status of sea otters to be "special concern". Alaska is the central area of the sea otter's range. In 1973, the population in Alaska was estimated at between 100,000 and 125,000 animals. By 2006, though, the Alaska population had fallen to an estimated 73,000 animals. A massive decline in sea otter populations in the Aleutian Islands accounts for most of the change; the cause of this decline
6942-727: 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
7031-424: The thick fur and the skin where air is trapped and heated by the body. Cold water is kept completely away from the skin and heat loss is limited. However, a potential disadvantage of this form of insulation is compression of the air layer as the otter dives, thereby reducing the insulating quality of fur at depth when the animal forages. The fur is thick year-round, as it is shed and replaced gradually rather than in
7120-439: The torso to conserve heat, whereas on particularly hot days, the hind feet may be held underwater for cooling. The sea otter's body is highly buoyant because of its large lung capacity – about 2.5 times greater than that of similar-sized land mammals – and the air trapped in its fur. The sea otter walks with a clumsy, rolling gait on land, and can run in a bounding motion. Long, highly sensitive whiskers and front paws help
7209-1008: 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
7298-557: The westernmost limit of the hunting grounds off the northern Japanese island of Hokkaido and the easternmost limit off Punta Morro Hermosa about 21 + 1 ⁄ 2 miles (34.6 km) south of Punta Eugenia , Baja California's westernmost headland in Mexico . In about two-thirds of its former range, the species is at varying levels of recovery, with high population densities in some areas and threatened populations in others. Sea otters currently have stable populations in parts of
7387-673: The wharf in Santa Cruz, California. Under each foreleg, the sea otter has a loose pouch of skin that extends across the chest. In this pouch (preferentially the left one), the animal stores collected food to bring to the surface. This pouch also holds a rock, unique to the otter, that is used to break open shellfish and clams. At the surface, the sea otter eats while floating on its back, using its forepaws to tear food apart and bring it to its mouth. It can chew and swallow small mussels with their shells, whereas large mussel shells may be twisted apart. It uses its lower incisor teeth to access
7476-454: The world population fell to 1,000–2,000 individuals living in a fraction of their historic range. A subsequent international ban on hunting, sea otter conservation efforts, and reintroduction programs into previously populated areas have contributed to numbers rebounding, and the species occupies about two-thirds of its former range. The recovery of the sea otter is considered an important success in marine conservation , although populations in
7565-529: 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
7654-433: Was considerably lighter than the average weight of otters in more sparse populations, at 39.3 kg (87 lb) in males and 25.2 kg (56 lb) in females Presumably less populous otters are more able to monopolize food sources, For its size, the male otter's baculum is very large, massive and bent upwards, measuring 150 mm ( 5 + 7 ⁄ 8 in) in length and 15 mm ( 9 ⁄ 16 in) at
7743-661: Was estimated at 16,000 before the fur trade decimated the population, leading to their assumed extinction. Today's population of California sea otters are the descendants of a single colony of about 50 sea otters located near Bixby Creek Bridge in March 1938. Their principal range has gradually expanded and extends from Pigeon Point in San Mateo County to Santa Barbara County . Sea otters were once numerous in San Francisco Bay . Historical records revealed
7832-458: Was formerly sometimes referred to as the "sea beaver ". Three subspecies of the sea otter are recognized with distinct geographical distributions. Enhydra lutris lutris ( nominate ), the Asian sea otter , ranges across Russia's Kuril Islands northeast of Japan, and the Commander Islands in the northwestern Pacific Ocean. In the eastern Pacific Ocean, E. l. kenyoni , the northern sea otter ,
7921-407: Was home to both the oldest recorded female, Etika, who lived to the age of 28, and the oldest recorded male, Adaa , who lived to be 22 years 8 months. Sea otters in the wild often develop worn teeth , which may account for their apparently shorter lifespans. Sea otters live in coastal waters 15 to 23 metres (49 to 75 ft) deep, and usually stay within a kilometre ( 2 ⁄ 3 mi) of
#778221