Sea Otters

Article #1

This aquatic member of the weasel family is found along the coasts of the Pacific Ocean in North America and Asia. The sea otter spends most of its time in the water but, in some locations, comes ashore to sleep or rest. Sea otters have webbed feet, water-repellent fur to keep them dry and warm, and nostrils and ears that close in the water. Sea otters often float at the water's surface, lying on their backs in a posture of serene repose. They sleep this way, often gathered in groups. Otters sometimes float in forests of kelp, or giant seaweed, in which they entangle themselves to provide anchorage in the swirling sea. These aquatic otters do more than sleep while floating on their backs. They are often seen with a clam or mussel and a rock that has been deftly snared from the ocean floor. Otters will place the rock on their chests, and repeatedly smash the shellfish against it until it breaks open to reveal the tasty meal inside. They also dine on such aquatic creatures as sea urchins, crabs, squid, octopuses, and fish. Sea otters are the only otters to give birth in the water. Mothers nurture their young while floating on their backs. They hold infants on their chests to nurse them, and quickly teach them to swim and hunt. Sea otters are meticulously clean. After eating, they wash themselves in the ocean, cleaning their coat with their teeth and paws. They have good reason to take care of their coats—it helps them to remain waterproof and insulated against the cold. Sea otters have thick under fur that traps air to form an insulating layer against the chilly waters (they have no insulating fat). This coat is invaluable to otters, but it has worth to some humans as well. Sea otters were hunted for their fur to the point of near extinction. Early in the 20th century only 1,000 to 2,000 animals remained. Today, 100,000 to 150,000 sea otters are protected by law.

-National Geographic

-http://animals.nationalgeographic.com/animals/mammals/sea-otter/

- 1996-2011 National Geographic

This article is about everything about sea otters from their location, what they eat, and how and where they live. Sea otters spend most of their time in the water, mostly on the water’s surface. They sleep this way also; floating on their backs or they can come ashore to sleep or just to rest. Sea otters are known to be quite clean. After they eat, they always wash themselves in the water and it states in this article the reason for this is that “it helps them remain waterproof and insulated against the cold,” which I found very interesting. When I went to the Aquarium of the Pacific, and observed the sea otters, I noticed the way they float on the surface. They truly do lie on their backs when floating which was cool to watch. I also noticed their webbed feet which this article explained the reason why they have webbed feet is to keep they dry and warm. Sea otters are very interesting to watch, observe, and to learn. I learned a lot from just reading this article and actually seeing them in person.

Article #2

According to Hu (1996), there are three subspecies of Ephedra lutris. The Southern sea otter is known as Enhydra lutris nereis, the Russian sea otter is Enhydra lutris lutis the Alaskan sea otter is Enhydra lutris kenyoni, and the Asian sea otter is Enhydra lutris gracilis. While there are four subspecies, I will only be talking about the Southern and Alaskan sea otters due to lack of information on the other subspecies. Sea Otters are about four feet long and weigh an average of 65 pounds for males and 45 pounds for females. They’ve got strong canines and strong molars to tear and crush their food. Their lung capacity is 2.5 times the size of land mammals of the same size. They have good eyesight and use their whiskers to sense vibrations in the water. They’re known for the use of tools when eating. Because they love mollusks, sea otters will use rocks as hammers and anvils to help open the shells. Because they have no blubber, they must eat 25% of their body weight in food to maintain their high metabolism. Grooming is important as it forces air bubbles into their fur that acts as insulation (Friends of the Sea Otter). Sea otters prefer the temperate climate. They’re foragers who seek their food on the bottom of rocky and soft-sediment subtidal habitats in coastal waters (VanBlaricom & Estes 1988). They also make their home among the kelp forests. Sea otters, in fact, help the kelp forests by eating the number one herbivore in the region: sea urchins. The original habitat of the sea otter ranged from the Kurile Islands of Japan, to the Aleutian Chain of Alaska, along the coasts of Washington and Oregon, and down the coast of California to Baja California (Friends of the Sea Otter). There used to be a continuous distribution of sea otters but their thick pelts made them the favorite quarry of early fur traders in the 1700’s and 1800’s. Also contributing to the demise of the sea otter is pollution. Sea otters have extremely thick fur. Estimates put the number of hairs per square inch at about one million (Cohn 1998) while dogs only have about 60,000 hairs per square inch. In the 18th century, otter fur was prized in the Russian, Chinese, and Japanese courts (Woolfenden 1979). Land otters were hunted extensively and became scarce. During an expedition to find a land passage between Asia and North America, Vitus Bering discovered the Aleutian Islands and Alaska. Stranded on an island on the way back to Russia, Bering and some 30 others died. The survivors, among them a scientist named Georg Wilhelm Steller, subsisted on sea otters and a sea cow until they were able to build a new ship from the original, damaged ship. The remaining members of the expedition would bring back to Russia 900 otter pelts that would fetch a price of $30,000 (Woolfenden 1979). In 1911, the International Fur Seal Treaty saved the sea otters, as well as other marine mammals being hunted for their pelts, from extinction. Under the 1972 Marine Mammal Protection Act, sea otters have been listed as a "threatened" species in 1977. According to Cohn (1998), there were an estimated 150,000 sea otters in Alaska and Aleutian Islands, 17,000-18,000 in Russia and northern Japan, and 2200 in California, 1000 in British Columbia, and 500 in Washington State. However, recent events have changed some of these numbers dramatically. Sea otters are the smallest of marine mammal species. According to VanBlaricom & Estes (1988), sea otters fall into two categories: those that eat primarily fish and those that eat primarily invertebrates. The former have evolved with sharp teeth for cutting and the latter have developed strong molars for crushing their food. They also note that scientists have traced the lineage of the modern sea otter back to an extinct species called Enhydritherium that lived in the late Miocene in Europe and North America. Sea otters occupy much of their historical range (VanBlaricom & Estes 1988). They are found along the Kuril Islands off of Russia, the Aleutian Islands south of the Bering Sea up to the southern coast of Alaska, and off the coast of Central California. Their numbers have been reduced by heavy exploitation in the 18th and 19th centuries for their pelts. Sea otters are believed to have their origins in the Old World and made their way to the New World (VanBlaricom & Estes 1988). While the exact dispersal routes for the primitive lutrinae aren’t known, there are theories as to what those possible paths might have been. According to VanBlaricom and Estes (1988), some suggestions include the sea otters using the Bering Land Bridge or the North Atlantic to get to the New World. It’s also noted that the species Enhydra lutris probably evolved in the North Pacific and hasn’t dispersed since.

-Tracy Benshoof

-5/21/99

-http://bss.sfsu.edu/holzman/courses/Spring99Projects/otter.htm

This article gives us brief information about sea otters’ habitat, history, evolution, and distribution. It goes in detail about the three types of sea otters; the Russian, Alaskan, and Asian sea otter. Their average weight is about 65 pounds for the male and 45 for the female. Sea otters mostly like to live in a temperature climate. What I found interesting about this article is that sea otters are the smallest of the marine mammal species. They are believed to originate in the Old War and into the New World. It stated in this article that sea otters had very thick fur which was weird because when I went to see them, it didn’t seem like they had that much fur like how it was explained. I think the fact that they were swimming, and they do swim fast, I couldn’t get a close look at their fur or the water just makes it harder to notice. I learned a few things about sea otters that I found interesting. The best part about this experience is just watching them go by. They are beautiful animals in every way.