10 Awesome Facts About Sea Otters
Sea otters have become icons of marine conservation on the West Coast of the U.S. With their furry bodies, whiskered faces and propensity to lay on their backs on the water, they are an easily-recognized marine mammal. Learn some fascinating facts about sea otters below.
Sea otters are related to weasels. Sea otters are carnivores in the Family Mustelidae - the group of animals that includes weasels, badgers, skunks, fishers, minks, river otters, and sea otters. These animals all have thick fur and short ears.
There is one species of sea otter - Enhyrda lutris, but there are three subspecies: the Russian northern sea otter (Enhyrda lutris lutris), which lives in the Kuril Islands, Kamchatka Peninsula, and Commander Islands off Russia; the northern sea otter (Enhyrda lutris kenyoni), which lives from the Aleutian Islands off Alaska, down to Washington state; and the southern sea otter (Enhyrda lutris nereis), which lives in southern California.
Unlike some marine mammals like whales, who would die if they were on land for too long, sea otters can go up onto land to rest, groom or nurse. They spend most of their lives in the water, however, and can live their entire lives in the water if they need to. Sea otters even give birth in the water.
Sea otters spend hours each day grooming their fur. Their fur is their insulation - unlike other marine mammals, sea otters don't have blubber, so their sole way of keeping warm is their fur. A sea otter's fur is made up of an undercoat and longer guard airs. Air around the fur is heated by the sea otter's body heat, and this air in turn keeps the sea otter warm.
Their dependence upon fur for warmth is why a sea otter is so threatened by oil spills (e.g., the Exxon Valdez, which killed at least several hundred sea otters, and affected the sea otter population in Prince William Sound for "well over a decade."). If oil covers a sea otter's fur, air cannot penetrate it and the sea otter will get too cold.
Sea otters eat fish, and marine invertebrates like crabs, urchins, sea stars, and abalone. Some of these animals have hard shells, making it difficult to get the meat inside. This isn't an issue for the sea otter, which uses rocks as tools to crack the shells of its prey.
Young sea otters are so buoyant that they can't dive underwater. Before they go foraging, the mother sea otter will wrap their young in a piece of kelp to keep them anchored in one spot.
Sea otters play an important role in the food web of the kelp forest, and influence even terrestrial species. When sea otters populations are healthy, urchin populations are kept in check, and kelp is abundant. Kelp provides shelter for a not only sea otters and their pups, but a variety of other marine organisms. A decline in sea otters (due to natural predation or other factors, such as if there was an oil spill) means that urchin populations explode, kelp decreases, and other marine species have less habitat.
A study published in 2008 showed that when sea otter populations were abundant, bald eagles preyed primarily on fish and sea otter pups, but when sea otter populations declined (due to predation by an increased populations of orcas), bald eagles preyed more on marine birds.
A 2012 study showed the role sea otters can play in reducing carbon dioxide in the atmosphere - if sea otter populations increase, urchin populations will be controlled and kelp forests will thrive. Kelp can absorb carbon dioxide from the atmosphere, and, the study found, "spreading kelp can absorb as much as 12 times the amount of CO2 from the atmosphere than if it were subject to ravenous sea urchins."
The sea otter's thick, luxurious fur was sought-after by hunters in the 17th and 18th century - so much so, that their worldwide population may have been decimated to only about 2,000 individuals by the early 1900's.
Sea otters first became protected from the fur trade by the International Fur Seal Treaty in 1911. Now, sea otters in the U.S. are protected under the Marine Mammal Protection Act and the southern sea otter is listed under the Endangered Species Act as "threatened."
While sea otter populations increased after protection, there have been recent declines in sea otters in the Aleutian Islands (thought to be from orca predation) and a decline or plateau in the populations in California.
Other than natural predators, threats to sea otters include pollution, diseases, parasites, entanglement in marine debris, and boat strikes.
•Sea otters are related to weasels.
Sea otters are related to weasels. Sea otters are carnivores in the Family Mustelidae - the group of animals that includes weasels, badgers, skunks, fishers, minks, river otters, and sea otters. These animals all have thick fur and short ears.
•There is only one species of sea otter.
There is one species of sea otter - Enhyrda lutris, but there are three subspecies: the Russian northern sea otter (Enhyrda lutris lutris), which lives in the Kuril Islands, Kamchatka Peninsula, and Commander Islands off Russia; the northern sea otter (Enhyrda lutris kenyoni), which lives from the Aleutian Islands off Alaska, down to Washington state; and the southern sea otter (Enhyrda lutris nereis), which lives in southern California.
•Sea otters live in the ocean, but can also live on land.
Unlike some marine mammals like whales, who would die if they were on land for too long, sea otters can go up onto land to rest, groom or nurse. They spend most of their lives in the water, however, and can live their entire lives in the water if they need to. Sea otters even give birth in the water.
•Sea otters need to keep clean.
Sea otters spend hours each day grooming their fur. Their fur is their insulation - unlike other marine mammals, sea otters don't have blubber, so their sole way of keeping warm is their fur. A sea otter's fur is made up of an undercoat and longer guard airs. Air around the fur is heated by the sea otter's body heat, and this air in turn keeps the sea otter warm.
Their dependence upon fur for warmth is why a sea otter is so threatened by oil spills (e.g., the Exxon Valdez, which killed at least several hundred sea otters, and affected the sea otter population in Prince William Sound for "well over a decade."). If oil covers a sea otter's fur, air cannot penetrate it and the sea otter will get too cold.
•Sea otters use tools.
Sea otters eat fish, and marine invertebrates like crabs, urchins, sea stars, and abalone. Some of these animals have hard shells, making it difficult to get the meat inside. This isn't an issue for the sea otter, which uses rocks as tools to crack the shells of its prey.
•Sea otters have built-in storage.
Sea otters have a baggy patch of skin under their forelimbs, and this is used for storage. They can keep extra food in this spot, and also store a favorite rock for cracking the shell of their prey.
•Young sea otters can't dive underwater.
Young sea otters are so buoyant that they can't dive underwater. Before they go foraging, the mother sea otter will wrap their young in a piece of kelp to keep them anchored in one spot.
•Sea otters are social animals who live in "rafts."
Sea otters are social, and hang out together. But their groups, which are called "rafts," are formed of either females and their young, or males.
•Sea otters are important predators.
Sea otters play an important role in the food web of the kelp forest, and influence even terrestrial species. When sea otters populations are healthy, urchin populations are kept in check, and kelp is abundant. Kelp provides shelter for a not only sea otters and their pups, but a variety of other marine organisms. A decline in sea otters (due to natural predation or other factors, such as if there was an oil spill) means that urchin populations explode, kelp decreases, and other marine species have less habitat.
A study published in 2008 showed that when sea otter populations were abundant, bald eagles preyed primarily on fish and sea otter pups, but when sea otter populations declined (due to predation by an increased populations of orcas), bald eagles preyed more on marine birds.
A 2012 study showed the role sea otters can play in reducing carbon dioxide in the atmosphere - if sea otter populations increase, urchin populations will be controlled and kelp forests will thrive. Kelp can absorb carbon dioxide from the atmosphere, and, the study found, "spreading kelp can absorb as much as 12 times the amount of CO2 from the atmosphere than if it were subject to ravenous sea urchins."
•Sea otters were hunted for their fur.
The sea otter's thick, luxurious fur was sought-after by hunters in the 17th and 18th century - so much so, that their worldwide population may have been decimated to only about 2,000 individuals by the early 1900's.
Sea otters first became protected from the fur trade by the International Fur Seal Treaty in 1911. Now, sea otters in the U.S. are protected under the Marine Mammal Protection Act and the southern sea otter is listed under the Endangered Species Act as "threatened."
While sea otter populations increased after protection, there have been recent declines in sea otters in the Aleutian Islands (thought to be from orca predation) and a decline or plateau in the populations in California.
Other than natural predators, threats to sea otters include pollution, diseases, parasites, entanglement in marine debris, and boat strikes.
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