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<v Speaker 1>Welcome to the I Can't Sleep Podcast, where I help

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<v Speaker 1>you drift off one fact at a time. I'm your host,

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<v Speaker 1>Benjamin Boster, and today's episode is about otters. Otters are

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<v Speaker 1>carnivorous mammals in the subfamily Lutrini. The fourteen extant otter

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<v Speaker 1>species are all semi aquatic, both freshwater and marine. Lutrinia

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<v Speaker 1>is a branch of the Mostellite family, which includes weasels, badgers, mink,

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<v Speaker 1>and wolverines, among other animals. Otters are distinguished by their long,

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<v Speaker 1>slim bodies, powerful webbed feet for swimming, and their dense fur,

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<v Speaker 1>which keeps him warm and buoyant in water. There are

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<v Speaker 1>playful animals, engaging in activities like sliding into water on

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<v Speaker 1>natural slides and playing with stones. Otters exhibit a varied

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<v Speaker 1>life cycle, with a gestation period of about sixty to

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<v Speaker 1>eighty six days, and offspring typically stay with their family

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<v Speaker 1>for a year. They can live up to sixteen years,

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<v Speaker 1>with their diet mainly consisting of fish and sometimes frogs, birds,

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<v Speaker 1>or shell fish, depending on the species. There are fourteen

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<v Speaker 1>known species of otters, ranging in size and habitat preferences,

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<v Speaker 1>with some species adapted to cold waters, requiring a high

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<v Speaker 1>metabolic rate for warmth. Otters hold a place in various cultures,

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<v Speaker 1>mythology and religion, symbolizing different attributes and stories, from Norse

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<v Speaker 1>mythology to Native American totems and Asian folklore, where they

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<v Speaker 1>are sometimes believed to possess shape shifting abilities. The word

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<v Speaker 1>otter derives from the Old English word odour. This and

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<v Speaker 1>cognate words in other Indo European languages ultimately stem from

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<v Speaker 1>the Proto Indo European word wooder, which also gave rise

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<v Speaker 1>to the English word water. The gestation period in otters

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<v Speaker 1>is about sixty to eighty six days. The new born

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<v Speaker 1>pop is cared for by the female, male and older offspring.

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<v Speaker 1>Females reach sexual mature at approximately two years of age

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<v Speaker 1>and males at approximately three years. The den is built

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<v Speaker 1>under tree roots or a rocky cairn more common in Scotland.

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<v Speaker 1>It is lined with moss and grass. After one month,

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<v Speaker 1>the pup can leave the den and after two months

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<v Speaker 1>sick and swim. The pup lives with its family for

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<v Speaker 1>approximately one year. Otters live up to sixteen years. There By,

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<v Speaker 1>nature playful and frolic in the water with their pups.

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<v Speaker 1>Its usual food is fish and further downriver eels, but

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<v Speaker 1>it may also sample frogs and birds. Otters have long,

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<v Speaker 1>slim bodies and relatively short limbs. Their most striking anatomical

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<v Speaker 1>features are the powerful webbed feet used to swim and

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<v Speaker 1>their seal likabilities for holding breast underwater. Most have sharp

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<v Speaker 1>claws on their feet, and all except the sea otter

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<v Speaker 1>have long, muscular tails. The thirteen species range in adult

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<v Speaker 1>size from ero point six to one point eight meters

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<v Speaker 1>in length and one to forty five kilograms in weight.

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<v Speaker 1>The Asians small clod otter is the smallest otter species,

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<v Speaker 1>and the giant otter and sea otter are the largest.

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<v Speaker 1>They have very soft, insulated underfur, which is protected by

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<v Speaker 1>an outer layer of long guard hairs. This traps a

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<v Speaker 1>layer of air which keeps them dry, warm, and somewhat

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<v Speaker 1>buoyaned underwater. Several otter species live in cold waters and

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<v Speaker 1>have high metabolic rates to help keep them warm. Eurasian

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<v Speaker 1>otters must eat fifteen percent of their body weight each day,

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<v Speaker 1>and see otters twenty to twenty five percent, depending on

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<v Speaker 1>the temperature. In water as warm as ten degrees celsius,

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<v Speaker 1>an otter needs to catch one hundred grams of fish

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<v Speaker 1>per hour to survive. Most species hunt for three to

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<v Speaker 1>five hours each day, and nursing mothers up to eight

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<v Speaker 1>hours each day. For most otters, fish is the staple

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<v Speaker 1>of their diet, is often supplemented by frogs, crayfish, and crabs.

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<v Speaker 1>Some otters are experts at opening shellfish, and others will

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<v Speaker 1>feed on available small mammals or birds. Prey dependence leaves

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<v Speaker 1>otters very vulnerable to prey depletion. Sea otters are hunters

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<v Speaker 1>of clams, sea urchins, and other shelled creatures. They are

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<v Speaker 1>notable for their ability to use stones to break open

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<v Speaker 1>shellfish on their bellies. This skill must be learned by

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<v Speaker 1>the young. Otters are active hunters, chasing prey in the

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<v Speaker 1>water or searching the beds of rivers, lakes, or the seas.

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<v Speaker 1>Most species live beside water, but river otters usually enter

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<v Speaker 1>it only to hunt or travel, otherwise spending much of

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<v Speaker 1>their time on land to prevent their fur becoming waterlogged.

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<v Speaker 1>Sea otters are considerably more aquatic and live in the

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<v Speaker 1>ocean for most of their lives. Otters are playful animals

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<v Speaker 1>and appear to engage in various behaviors for sheer enjoyment,

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<v Speaker 1>such as making water slides and sliding on them into

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<v Speaker 1>the water. They may also find and play with small stones.

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<v Speaker 1>In nineteen ninety an otter was observed belly sliding in Singapore,

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<v Speaker 1>likely as a form of amusement. Different species vary in

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<v Speaker 1>their social structure, some being largely solitary, while others live

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<v Speaker 1>in groups and a few species. These groups may be

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<v Speaker 1>fairly large for many generations. Fishermen in southern Bangladesh have

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<v Speaker 1>bred smooth coated otters and use them to chase fish

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<v Speaker 1>into their nets. Once a widespread practice passed down from

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<v Speaker 1>father to son throughout many communities in Asia. This traditional

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<v Speaker 1>use of domesticated wild animals is still in practice in

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<v Speaker 1>the district of Noreal, Bangladesh. Norse mythology tells of the

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<v Speaker 1>dwarf foder habitually taking the form of an otter. The

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<v Speaker 1>myth of Otter's ransom is the starting point of the

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<v Speaker 1>Volsunga saga. In Irish mythology, the character lie Ban was

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<v Speaker 1>turned from a woman into a mermaid half human and

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<v Speaker 1>half salmon, and given three hundred years of life to

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<v Speaker 1>roam the oceans. Her lap dog assumed the form of

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<v Speaker 1>an otter and shared her prolonged lifetime and her extensive wanderings.

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<v Speaker 1>In some Native American cultures, otters are considered totem animals.

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<v Speaker 1>In popular Korean mythology, it is told that people who

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<v Speaker 1>see and otter will attract rain clouds for the rest

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<v Speaker 1>of their lives. In the Buddhist Chakada tales the Otters

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<v Speaker 1>and the Wolf, two otters agreed to let a wolf

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<v Speaker 1>settle their dispute in dividing their cod fish, but it

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<v Speaker 1>was taken away by the cunning wolf. In Japanese, otters

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<v Speaker 1>are called the Kawauso. In Japanese folklore, they fool humans

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<v Speaker 1>in the same way as foxes and tanuki. In the notoregion,

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<v Speaker 1>Ishikawa Prefecture, there are stories where they shape shift into

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<v Speaker 1>beautiful women or children wearing checker pattern clothing. If a

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<v Speaker 1>human attempts to speak to one, they will answer oarya

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<v Speaker 1>and then answer aarya. If anybody asks them anything, they

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<v Speaker 1>say cryptic things like kawai. The sea otter is a

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<v Speaker 1>marine mammal native to the coasts of the northern and

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<v Speaker 1>eastern North Pacific Ocean. Adult sea otters typically weigh between

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<v Speaker 1>fourteen and forty five kilograms making them the heaviest members

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<v Speaker 1>of the weasel family, but among the smallest marine mammals.

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<v Speaker 1>Unlike most marine mammals, the sea otter's primary form of

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<v Speaker 1>insulation is an exceptionally thick coat of fur, the densest

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<v Speaker 1>in the animal kingdom. Although it can walk on land,

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<v Speaker 1>this sea otter is capable of living exclusively in the ocean.

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<v Speaker 1>The sea yotter inhabits near shore environments, where it dives

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<v Speaker 1>to the seafloor to forage. It preys mostly on marine

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<v Speaker 1>invertebrates such as sea urchins, various mollusks and crustaceans, and

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<v Speaker 1>some species of fish. Its foraging and eating habits are

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<v Speaker 1>noteworthy in several respects. Its use of rocks to discy,

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<v Speaker 1>lodge prey, and to open shells makes it one of

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<v Speaker 1>the few mammal species to use tools in most of

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<v Speaker 1>its range. It is a key stone species, controlling sea

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<v Speaker 1>urchin populations, which would otherwise inflict extensive damage to kelp

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<v Speaker 1>forest ecosystems. Its diet includes prey species that are also

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<v Speaker 1>valued by humans as food, leading to conflicts between sea

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<v Speaker 1>otters and fisheries. The sea otter is the heaviest the

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<v Speaker 1>giant otter is longer but significantly slimmer member of the

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<v Speaker 1>family Mustellity, a diverse group that includes the fourteen otter

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<v Speaker 1>species and terrestrial animals such as weasels, badgers, and minks.

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<v Speaker 1>It is unique among the mustellids and not make dens

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<v Speaker 1>or burrows, and in being able to live its entire

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<v Speaker 1>life without leaving the water. The only living member of

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<v Speaker 1>the genus in hydra, the sea otter is so different

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<v Speaker 1>from other Mustellid species that as recently as nineteen eighty two,

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<v Speaker 1>some scientists believe it was more closely related to the

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<v Speaker 1>earless seals. Genetic analysis syndicates the seaotter in its closest

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<v Speaker 1>sext and relatives, which include the African speckle throated otter,

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<v Speaker 1>Eurasian otter, African clalless otter, and Asian small cloud otter,

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<v Speaker 1>shared an ancestor approximately five million years ago. The sea

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<v Speaker 1>otter is one of the smallest marine mammal species, but

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<v Speaker 1>it is the heaviest mustelid. Male sea otters usually weigh

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<v Speaker 1>twenty two to forty five kilograms and are one point

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<v Speaker 1>two to one point five meters in length. Those specimens

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<v Speaker 1>up to fifty four kilograms have been recorded females are smaller,

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<v Speaker 1>weighing fourteen to thirty three kilograms and measuring one to

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<v Speaker 1>one point four meters in length. The average weight for

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<v Speaker 1>adult sea otters that are in more densely populated areas

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<v Speaker 1>at twenty eight point three kilograms and males and twenty

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<v Speaker 1>one point one kilograms and females, was considerably lighter than

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<v Speaker 1>the average weight of otters and more sparse populations at

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<v Speaker 1>thirty nine point three kilograms in males and twenty five

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<v Speaker 1>point two kilograms and females. Presumably, less populous otters are

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<v Speaker 1>more able to monopoly food sources. Unlike most other marine mammals,

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<v Speaker 1>the sea otter has no blubber and relies on its

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<v Speaker 1>exceptionally thick fur to keep warm. With up to one

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<v Speaker 1>hundred fifty thousand strands of hair per square centimeter, its

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<v Speaker 1>fur is the densest of any animal. The fur consists

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<v Speaker 1>of long, waterproof guard hairs and short underfur. The guard

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<v Speaker 1>hairs keep the dense under fur layer dry. There is

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<v Speaker 1>an air compartment between the thick fur and the skin,

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<v Speaker 1>where air is trapped and heated by the body. Cold

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<v Speaker 1>water is kept completely away from the skin, and heat

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<v Speaker 1>loss is limited. However, a potential disadvantage of this form

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<v Speaker 1>of insulation is compression of the air layer as the

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<v Speaker 1>otter dives, thereby reducing the insulating quality of fur at depths.

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<v Speaker 1>When the animal forages, the fur is thick year round,

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<v Speaker 1>as it is shed and replaced gradually rather than in

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<v Speaker 1>a distinct molting season. As the ability of the guard

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<v Speaker 1>hairs to repel water depends on utmost cleanliness, the sea

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<v Speaker 1>otter has the ability to reach and groom fur on

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<v Speaker 1>any part of its body, taking advantage of its loose

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<v Speaker 1>skin and an unusually supple skeleton. The coloration of the

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<v Speaker 1>pellage is usually deep brown with silver gray speckles, but

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<v Speaker 1>it can range from yellowish or grayish brown to almost

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<v Speaker 1>black in adults. The head, throat, and chest are lighter

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<v Speaker 1>in color than the rest of the body. The sea

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<v Speaker 1>otter displays numerous adaptations to its marine environment. The nostrils

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<v Speaker 1>and small ears can close. The hind feet, which provide

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<v Speaker 1>most of its propulsion in swimming, are long, broadly flattened,

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<v Speaker 1>and fully webbed. The fifth digit on each hind foot

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<v Speaker 1>is longest, facilitating swimming while on its back but making

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<v Speaker 1>walking difficult. The tail is fairly short, thick, slightly flattened,

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<v Speaker 1>and muscular. The front paws are short with retractable claws,

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<v Speaker 1>with tough pads on the palms that enable gripping slippery prey.

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<v Speaker 1>The bones show osteously euroses, increasing their density to reduce buoyancy.

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<v Speaker 1>The sea otter presents an insight into the evolutionary process

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<v Speaker 1>of the mammalian evasion of the aquatic environment, which has

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<v Speaker 1>occurred numerous times over the course of mammalian evolution. Having

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<v Speaker 1>only returned to the sea about three million years ago,

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<v Speaker 1>sea otters represent a snapshot at the earliest point of

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<v Speaker 1>the transition from fur to blubber. In sea otters, fur

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<v Speaker 1>is still advantageous given their small nature and division of

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<v Speaker 1>lifetime between the aquatic and terrestrial environments. However, as sea

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<v Speaker 1>otters evolve and adapt to spending more and more of

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<v Speaker 1>their lifetimes in the sea, the convergent evolution of blubber

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<v Speaker 1>suggests that the reliance on fur for insulation would be

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<v Speaker 1>replaced by a dependency on blubber. This is particularly true

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<v Speaker 1>due to the diving nature of the sea otter. As

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<v Speaker 1>dives become lengthier and deeper, the air layer's ability to

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<v Speaker 1>retain heat or buoyancy decreases, while blubber remains efficient at

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<v Speaker 1>both of those functions. Blubber can also additionally serve as

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<v Speaker 1>an energy source for deep dives, which would most likely

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<v Speaker 1>prove advantageous over fur in the evolutionary future of sea otters.

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<v Speaker 1>The sea otter propels itself under water by moving the

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<v Speaker 1>rear end of its body, including its tail and hind feet,

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<v Speaker 1>up and down, and is capable of speeds of up

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<v Speaker 1>to nine kilometers per hour. When under water, its body

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<v Speaker 1>is long and streamlined, with a short forelimbs pressed closely

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<v Speaker 1>against the chest. When at the surface, it usually floats

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<v Speaker 1>on its back and moves by skulling its feed and

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<v Speaker 1>tail from side to side. At rest, all fore limbs

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<v Speaker 1>can be folded under the torso to conserve heat, whereas

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<v Speaker 1>on particularly hot days the hind feet may be held

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<v Speaker 1>under water for cooling. The sea otter's body is highly

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<v Speaker 1>buoyant because of its large lung capacity about two point

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<v Speaker 1>five times greater than that of similar sized land mammals

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<v Speaker 1>and the air trapped in its fur. The sea otter

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<v Speaker 1>walks with a clumsy rolling gait on land and can

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<v Speaker 1>run in a bounding motion. Long, highly sensitive whiskers and

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<v Speaker 1>front paws help the sea otter find prey by touch

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<v Speaker 1>when waters are dark or murky. Researchers have noted when

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<v Speaker 1>they approach in plain view, sea otters react more rapidly

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<v Speaker 1>when the wind is blowing towards the animals, indicating a

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<v Speaker 1>sense of smell as more important than sight as a

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<v Speaker 1>warning sense. Other observations indicate the sea otter's sense of

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<v Speaker 1>sight is useful above and below the water, although not

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<v Speaker 1>as good as that of seals. Its hearing is neither

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<v Speaker 1>particularly acute nor poor in adults thirty two teas, particularly

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<v Speaker 1>the molars, are flattened and rounded for crushing rather than

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<v Speaker 1>cutting food. Seals and sea lions are the only carnivores

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<v Speaker 1>with two pairs of lower incisor teeth rather than three.

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<v Speaker 1>The adult dental formula is three point one point three

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<v Speaker 1>point one over two point one point three point two.

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<v Speaker 1>The teas and bones are sometimes stained purple as a

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<v Speaker 1>result of ingesting sea urchins. The sea otter has a

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<v Speaker 1>metabolic rate two or three times that of comparatively sized

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<v Speaker 1>terrestro mammals. It must eat an estimated twenty five to

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<v Speaker 1>thirty eight percent of its own body weight and food

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<v Speaker 1>each day to burn the calories necessary to counteract the

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<v Speaker 1>loss of heat due to the cold water environment. Its

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<v Speaker 1>digestive efficiency is estimated at eighty to eighty five percent,

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<v Speaker 1>and food is digested and past in as little as

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<v Speaker 1>three hours. Most of its need for water is met

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<v Speaker 1>through food, although in contrast to most other marine mammals,

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<v Speaker 1>it also drinks seawater. Its relatively large kidneys enable it

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<v Speaker 1>to derive fresh water from seawater and excrete concentrated urine.

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<v Speaker 1>The sea otter is diurnal. It is a period of

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<v Speaker 1>foraging and eating in the morning, starting about an hour

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<v Speaker 1>before sunrise, then rests or sleeps in midday. Foraging resumes

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<v Speaker 1>for a few hours in the afternoon and subsides before sunset,

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<v Speaker 1>and a third foraging period may occur around midnight. Females

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<v Speaker 1>with pups appear to be more inclined and defeate at nine.

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<v Speaker 1>Observations of the amount of time a sea yachtter must

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<v Speaker 1>spend each day foraging range from twenty four percent to

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<v Speaker 1>sixty percent, apparently depending on the availability of food in

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<v Speaker 1>the area. Sea otters spend much of their time grooming,

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<v Speaker 1>which consists of cleaning the fur, untangling, knots, removing loose fur,

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<v Speaker 1>rubbing the fur to squeeze out water and introduce air,

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<v Speaker 1>and blowing air into the fur. To casual observers, it

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<v Speaker 1>appears as if the animals are scratching, but they are

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<v Speaker 1>not known to have rice or other parasites in the fur.

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<v Speaker 1>When eating, sea oatters roll in the water frequently, apparently

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<v Speaker 1>to wash food scraps from their fur. The sea otter

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<v Speaker 1>hunts in short dives, often to the sea floor. Although

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<v Speaker 1>it can hold its breath for up to five minutes,

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<v Speaker 1>its dives typically last about one minute and not more

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<v Speaker 1>than four minutes. It is the only marine animal capable

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<v Speaker 1>of lifting and turning over rocks, which it often does

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<v Speaker 1>with its front paws when searching for prey. The sea

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<v Speaker 1>otter may also pluck snails and other organisms from kelp

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<v Speaker 1>and dig deep into underwater mud for clams. It is

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<v Speaker 1>the only marine mammal that catches fish with its fore

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<v Speaker 1>paws rather than with its teeth. Under each fore leg,

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<v Speaker 1>the sea otter has a loose pouch of skin that

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<v Speaker 1>extends across the chest. In this pouch, the animal stores

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<v Speaker 1>collected food to bring to the surface, and sometimes a

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<v Speaker 1>rock that is used to break open shellfish and clams

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<v Speaker 1>at the surface. The sea otter eats while floating on

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<v Speaker 1>its back, using its fore paws to tear food apart

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<v Speaker 1>and bring it to its mouth. It can chew and

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<v Speaker 1>swallow small muscles with their shells, whereas large muscle shells

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<v Speaker 1>may be twisted apart. It uses its lower incisor teeth

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<v Speaker 1>to access the meat and shellfish. Although each adult and

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<v Speaker 1>independent juvenile forages alone, sea otters tend to rest together

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<v Speaker 1>in single sex groups called rafts. A raft typically contains

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<v Speaker 1>ten to one hundred animals, with male rafts being larger

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<v Speaker 1>than female ones. The largest raft ever seen contain over

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<v Speaker 1>two thousand otters. To keep themselves from drifting out to sea.

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<v Speaker 1>When resting and eating, sea otters may wrap themselves in kelp.

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<v Speaker 1>The species exhibits a variety of vocal behaviors. The cry

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<v Speaker 1>of a pup is often compared to that of a goal.

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<v Speaker 1>Females coup when they are apparently content, Males may grunt instead.

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<v Speaker 1>Sea otters in captivity have been observed forming sibling like

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<v Speaker 1>bonds with each other. Two females at the shed aquarium,

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<v Speaker 1>Kiana and Kyukos, maintained a big sister little sister relationship

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<v Speaker 1>with the younger Kayukos following around the older Kiana and

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<v Speaker 1>mimicking her playful interactions with her Richmond toys. Formal assessment

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<v Speaker 1>of social network formation and maintenance among sea otters has

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<v Speaker 1>not been performed, largely because researchers had simply assumed that

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<v Speaker 1>rafts were composed of randomly assembled collections of individuals that

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<v Speaker 1>aggregated after solitary foraging. However, according to UC Santa Cruz

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<v Speaker 1>professor Tim Tinker, preliminary analysis of long term spatial associations

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<v Speaker 1>between tagged sea otters and Monterey Bay indicates that several

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<v Speaker 1>distinct clusters occur within the large aggregations. Some individuals also

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<v Speaker 1>show consistent associations over many years. As a result, formal

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<v Speaker 1>network analysis for sea otters may reveal important information on

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<v Speaker 1>the species in its social structures. Sea yotters have demonstrated

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<v Speaker 1>the capacity for social learning, with knowledge passed down both

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<v Speaker 1>vertically from mom to pop and horizontally within groups, although

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<v Speaker 1>whether or not they display a full fledged culture remains

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<v Speaker 1>unknown and under researched. Sea otters live in coastal waters

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<v Speaker 1>fifteen to twenty three meters deep and usually stay within

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<v Speaker 1>a kilometer of the shore. They are found most often

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<v Speaker 1>in areas with protection from the most severe ocean winds,

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<v Speaker 1>such as rocky coastlines, sik kelp forests, and barrier reefs.

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<v Speaker 1>Although they are most strongly associated with rocky substrates, sea

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<v Speaker 1>otters can also live in areas where the seafloor consists

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<v Speaker 1>primarily of mud, sand, or silt. Their northern range is

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<v Speaker 1>limited by ice, as sea otters can survive amidst drift ice,

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<v Speaker 1>but not land fast ice. Individuals generally occupy a home

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<v Speaker 1>range a few kilometers long and remain there year round.