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Species Profile: Sea Otter | ||||
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Sea Otters are unique marine mammals in that they use tools such as rocks to open their prey such as the shells of abalone. These social otters float in rafts in the Pacific Ocean just offshore. They have extraordinarily dense fur to keep them warm and are the heaviest otter species. Most mammals fur sheds rain and water, and keeps them warm by trapping air in the underfur (like a down jacket). In the summer, the mammal would shed most of its underfur, like changing into a less heavy coat. That works wonderfully in the air, but it doesn't work at all in water. The Sea Otters fur keeps warm also by trapping air in its coat, but the otters coat does not shed. They have two sets of hair: longer guard hairs and dense underfur. The guardhairs, when clean, are waterproof, protecting the underfur which traps a layer of air to provide insulation. The use of air as insulation is very efficient, providing four times the insulation of the same amount of fat or blubber. If the hairs are dirty or clogged with oil, then the sea otters coat won't be waterproof and the sea otter will die from the cold. You can see now why Sea Otters spend a large portion of time daily grooming themselves as they float on top of the water !   Sea otters are marine mammals, but they don't like to live out to sea. They prefer the coastal area where it doesn't get deeper than thirty meters. Why? Otters get their food from the sea bottom, and they can only dive so deep in a single breath of air. If an otter tries, it possibly could hold its breath for 5 minutes, but even then it would be under great stress. Usually otters only stay under for thirty to ninety seconds.  The Sea Otter eats about 30% of their body weight daily because they have such a high metobolic rate, with a diet which includes clams, mussels, urchins, crabs and abalone. Sea Otters are the only tool-using marine mammal! They use a stone to break open shells of their prey as they float on their backs, using their backs as a table for the shell.
Originally, Sea Otters had chosen to forage for food along the seashore for food instead of gathering food inshore. It was like finding a treasure when the otters found the amount of food in the sea. Slowly, over many generations, the otters went more and more into the sea, until they began diving, and swiming. Now the otter could eat whenever it felt hungry, not just at high tide. There was another upside to their discovery: early Sea Otters were the only mammals that had found it. The early Sea Otter's only downside was that they couldn't keep warm in the cold water, which draws body heat ten times faster than air does. That is how their fur developed to be so dense to protect them in this environment. The Sea Otter has a method for catching food which is very good. The Sea Otter gets ready to dive, and with a huge breath, leaps into the water. It swims to the bottom, and starts searching for food. A comerant may follow the Sea Otter, and from the otters upturning of rocks, it can sometimes find a meal for itself. When the otter finds some food, like a shellfish, it will tuck it into loose skin folds in its armpits, which are like shopping bags to the otter. This is all done very quickly, and the otter works hard. It will return to the surface to either eat or just to get a breath and dive again. When it's underwater, it can us its extremely sensitive whiskers (vibrassae) to find a small crab or snail hiding in the seawed or a crevice. It might also use its forepaws to reach into crevices for limpets or chitons that it cannot see. With its surprisingly strong paws, they can easily go through kelp beds in search of crabs or snails. These skills also are of great use when catching one of the Sea Otters favorite foods, abalone. This has angered commercial abalone divers and surprised biologists trying to figure out how the otter releases the creature from the stone. An abalone has two methods of defence, one is a hard and heavy shell, the other its ability to clamp down with tremendous force when disturbed. It has been estimated that the abalone can exert suction equal to about four thousand times its own bodyweight. The abalone can be from fifteen to twenty five centemeters(six to ten inches) across and have up to a kilogram (a few pounds) of meat inside. The sea otter uses a large stone to get the abalone off the rock. The Sea Otter would hold the stone in both paws, and hammer the side of the shell at the rate of forty five blows in fifteen seconds! It may take two to three dives for abalone bashing, but the Sea Otters persistance will eventually pay off. Sea Otters are also good clam diggers, collecting many species, from the valubal pismo clam to the smaller sand clams and razor clams. Clams don't just sit there waiting to be picked up by some otter or recreational digger, they want to live, so consequently, the otter has to dig to get the clam. The clam can bury itself ten to fifty centimeters under the sand. Sea Otters love to explore new foods. Once a Sea Otter living in Monterey discovered the connections between soda cans and one of it's favorite foods, octopus. Octopi can go through small openings very much like a water balloon. The otter had discovered that some small octopi were taking up residence in trash soda cans that had been thrown into the water. It took him about thirty seconds to open a can and take out a little octopus. Otters eating habits are also key to the environment around them, like a baromter on the health of the surrounding marine environment. If the otters like eating sea urchins (one of their favorites), then the sea urchin population goes down, but the kelp flourishes (because the amount of urchins eating them are down), and the snails and fish flourish too, because they can eat more kelp or be protected within its coverage. Snails, because they flourish, become the food of choice and so the process goes on. Without otters, one species flourishes (eg sea urchins), and it kills all of another (eg kelp), which kills another (eg snails and fish) and the ocean environment can change permanently. The season the pup is born differs depending on where they live. Southern Sea Otters in California give birth in the winter from around January to about March. On the other extreme, the Alaskan Sea Otter will give birth in the summer, when the water is milder and has less potential to lap over the young pups while they are on their mothers belly and would stop them from sleeping. Also, in the summer, pups are farther away from the land, where coyotes prowl for pups, and where eagles prey for food. Mothers are very protective of their young. If threatened, they will grab their young and dive. If they dive too much, the pup could drown. This is the reason that you should especially keep your distance from mothers with pups when otter watching. In about four weeks the passive pup will grow into a playfull toddler. As a toddler, The young otter will try to swim around while the mother dives for food. After time, the youngster will develop a jerky caterpillar style swim, which normally brings the toddler running into everything in their path. Although the otter is still too fluffy and bouyant to dive, it peers curiously underwater. In a few weeks, the little otter will be doing things like swimming and diving with its mother. The toddler is also now eating solid food, the mother has been prompting the little otter since it was only a few weeks with it. The little otter still suckels, though it is to big to sit on her stomach anymore. It lays crosswise forming a T with the mother, with its head on her tummy. At nap time, the mother and toddler usually will hold hands, or wrap themselves in kelp to keep themselves from drifting apart. One of the most memorable things about a young otter is their high pitched squeal. The first time it will squeal is when it figures out for the first time its mother has dived underwater. Later, when they become more energetic, the little otter will scream for everything it wants, or doesn't want. The reason for this loud, carrying scream is its value for survival. The scream can be heard for miles, so mothers can locate their children if they get lost. Sea otters are social, and tend to congregate in groups of gender, with pups and females in a group and males in another group. The pups also like to play together, developing playmates. The young otters are beyond energetic. They will attack and destroy anything they can within their reach. Mothers are often occupied with their kids. Young otters have a great life for the first five to six months. Then they might find a male crusing through the group of females and pups. Females that reject the male will slap, hiss, or snap at his face. If the male approaches the pup's mother, and she does not reject him, they will head to the edge of the raft. The pup, however much it tries to stop them, is ignored. Mating is violent and painful. The male and female will thrash about in the water, and in a few minutes, the female will come out with a red and ripped up nose where the male was holding on. It will eventually heal but may leave a scar. The male will stay with the female for the next few days, then it will be over. The father has no more role in the upbringing. Some scientists think that there is a period of around four months where there is delayed implantation and then the female will have another period of four weeks pregnancy. This adds up to a period of eight to nine months gestation period. Other scientists believe that the period is just four to five months. Under the best conditions, a mother would have eight to ten pups in their lifetime. But not everywhere is the best condition, so the average female will have five to six pups. Sea Otters, like other mammals, over-reproduce to allow for deaths due to predatation and disease. At around eight months, the young Sea Otter is ready to leave its mother. Now, instead of wanting to be close to its mother, it wants to strike out on its own. A male may travel 62 miles to find a group of males. He will reach maturity at eight or nine years. A female will reach her maturity at three years, and will have a pup at four or five years. Then the cycle continues... French: Lutre de mer German: Seeotter, Kalan Italian: Lontra di mare Russian: Kalan They toughed out a winter on the island. They spent their time gambling, and since they had no valuable possessions and no money, they used Otter skins as a new currency, killing the otters for no other reason than for their fur, this was a little peek in what was going to happen. When the snows started to melt, they set about to build a new ship. Although it was half the size of the St. Peter the boat was done on August 13, 1742. They had to sail soon for two reasons: another winter was coming, and the Sea Otters got smart and stayed away from them. By the time they left they had killed more than 900 Sea Otters in less than one year. When they got back to their home two months later, the local hunters decided they should visit these Islands that had so many Sea Otter. In the spring of 1743 Emilian Bassof, a military man, went with a merchant to the Bering Islands (near the Bering straight between Alaska and Russia) in a not-so-well-crafted boat without the aid of maps. He spent the winter there, and when he arrived at his home the next summer, he had sixteen hundred otter skins, two thousand blue fox skins, and two thousand fur seal skins. The next year, he made the trip back and brought more skins back. Ships of all shapes and sizes started making voyages to the Islands. The Promyshleniki started to move away from Bering Island and invade the Aleutian chain. The Aleutian Islands were inhabited. The Russians saw that the natives wore shirt like clothes made with Sea Otter fur and bird feathers. The Otters there could not be clubbed on land like on the Bering Island because natives had already hunted them. These Sea Otters were smart, if a human was near, they stayed in the water out of the hunter's reach. They tried everything they could think of, including guns and sailing up to the otters in their ships, but to no avail, the otters dove to safety with the slightest disturbance. The Russians traded what they had on their ships for the few Sea Otter pelts that the Aleuts had, but the Aleuts didn't have a reason to stockpile pelts. The Russians were getting really frustrated, they wanted to have every pelt of every animal they could see, and they would stop at nothing to get it, sometimes using hostages, enslavement, and murder. They survived the winter because of the little boats of the Aleuts, which they called baidarkas. The boats were marvels of engineering, they were made out of a wooden frame with sea lion skin, and they got the wood they needed from driftwood because wood was scarce. The boats were swift, silent, highly maneuverable, and it could hunt anywhere. The Russians made the Aleuts give them a certain number of otter pelts in order for their family to stay alive, when they resisted they were publicly tortured and put to death. The boats moved in groups, moving in on a raft of otters at a time and killing as many as possible. The skins traveled from the Aleutian chain to the mainland, then to China (about 3,000 miles from the mainland to China) where they were sold to wealthy merchants. It wasn't only Sea Otters hunted in the great hunt, it was many other animals too. Hundreds of black foxes, red foxes, blue foxes, and cross foxes were hunted and brought back every trip. Not only did those animals die, but the Aleutians culture was wiped out, disease spread through the country, ships were wreaked with thousands of Sea Otter pelts on them. Death and disaster were evident everywhere. Around 1768, the hunting ships left the Islands and went to Alaska. Thirty years the Great Hunt belonged to the Russians, then in 1776 Captain James Cook one of the greatest navigators and explorers decided to travel to Vancouver island. He went through the Northwest passage, looking for a northwest passage to China. In late March 1778, the Resolution and the Discovery, Cooks two vessels, sailed into Nootka Sound. Waves of natives came and clearly stated that they were prepared to trade. They offered sculls, hands, and Sea Otter pelts. Cook and his crew did not know the value of the Sea Otter pelts, but thought that they would be useful as they traveled farther north. They left Nootka Sound with supplies replenished. In his journal, Cook often noted the abundance of the Sea Otters. Little did he know he was following the coastal range of the Sea Otter. If Cook hadn't kept going north he would have witnessed the treachery displayed on the Sea Otters. As he traveled farther north along the Bering Sea he didn't find any more Sea Otters because they couldn't stand the really icy waters. Cook traveled to South to spend the winter. He landed in Hawaii, and was killed by the native people. They never found a northwest passage. On going home they stopped in the Chinese port of Canton. Canton is a lively trading port. One of the fur traders must have recognized the otter pelts that the men had used. When the people of Macao learned there were English vessels that had Sea Otter skins, the Englishmen were hoarded by eager merchants paying outrageous sums for the poorest scrap of fur. Suddenly the English recognized the value of these creatures. All the countries that could sent ships to Nootka Sound, including the United States, England, Europe, and Spain. Although the Americans, Europeans and English came for Sea Otter fur, the Spanish were there to kill them for food. Unlike the Russians, these people weren't interested in colonization, in fact they probably never saw a live Sea Otter because only the native people hunted them. An American trader in Boston learned that there were Sea Otters in California, so he proposed a partnership with a Russian called Alexander Baranof. Now that he had a crew and hunting ships, they went and collected the Sea Otter furs. The great hunt did not end at any given time, it slowly stopped as otters became more and more scarce. The Sea Otter was eventually Commercially extinct. Commercial extinction is not like they have totally died out, but everyone thinks they have. By 1830 the commercial Sea Otter hunt was over in the north. In 1867 the Russians sold Alaska to the USA and the Americans were eager to hunt the seals and otters for their fur. After the hunting season the otter had nearly been wiped out. The cute little peace loving Sea Otter had been tortured, shot. speared and clubbed. There are many questions asked about the great hunt which we cannot answer. A total of 123 ships reported killing 198,284 Sea Otters. The answers to these questions we can only guess.Although otters survived the Great hunt, they still had enemies. Humans, though now in more indirect ways, are still a very large threat to Sea Otters. Sea otters have natural enemies, too. For otters, Great white sharks and Orcas are enemies. They attack from under the otter, suddenly grabbing them from underwater. Oddly, Great white sharks don't eat the bodies of dead Sea otters. This leads some marine biologists to think that they are really after Seals, since dead seal bodies sink and otter bodies float. Even more recently, Orcas, also known as Killer whales, have been having a devastating affect of the Sea otter population. For Sea otter pups, the list of enemies is bigger. When left alone adrift in the water, a sea otter pup may be picked up by an eagle. If the young pup might drift off near to the shore and a coyote may take it. This only happens when the mother dives for food and the pup is left alone for a while.
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