ECOVIEWS: Sea otters are unique
Sea otters were added to my top 10 list of “most appealing mammals” after I watched a few swim around in Glacier Bay, Alaska. They joined pandas, beluga whales and, of course, puppies. But sea otters are not just cute, they are also one of the most resilient animals in the world. Which is a good thing, because in addition to living in a harsh habitat, they were nearly hunted to extinction for their fur.
Sea otters are not the only marine mammal, which includes dolphins, seals and whales, but these engaging creatures are the smallest. They belong in the weasel family, which includes badgers and skunks, but do not produce strong-smelling musk from the scent glands as the others do. Also in the one-of-a-kind category, sea otters are the only marine mammal having no blubber or other insulating layer of fat to help them survive in cold waters. Instead, they have the densest fur of all mammals (more than a million hairs per square inch), which traps air and provides insulation. The density of human hair is typically less than 3,000 hairs per square inch. Sea otters can weigh up to 100 pounds, making them one of the heaviest members of the weasel family. They can float with ease because of air trapped in the fur.
Their diet includes fish, crabs and other sea creatures, most of which they dive to the seafloor to obtain. Their lungs are more than twice the size of most comparably sized mammals. They can dive as deep as 300 feet and commonly stay under water 2 to 4 minutes. Among the myriad traits setting them apart from other mammals is their use of tools; sea otters are one of the few mammals known to employ tools. They use rocks to dislodge abalones, large mollusks which attach themselves to hard surfaces and must be pried loose. A sea otter, which typically swims on its back while eating, will set a rock on its belly and open the abalone shell by pounding it against the rock.
I rubbed my hand over a sea otter pelt once; it was the softest fur I have ever felt. Their fur was the reason for their near demise, initially at the hands of the Russians in the 1700s. In fact, the primary reason for the Russian occupation of Alaska before the United States bought it for a few cents an acre was the sea otter fur trade. At the time, sea otter pelts were considered the most valuable in the world.
The Russians recruited people native to the Aleutian Islands for the fur trade beginning in 1741, when the number of sea otters worldwide was estimated to be as high as 300,000. For 170 years, the unregulated killing of sea otters continued in most parts of the animal’s geographic range, from northern Japan, across the Aleutians, and down the western U.S. coast to Baja California. In 1911, four nations – Russia, Japan, Great Britain and the United States – established a treaty to protect the species. At the time fewer than 2,000 sea otters were left in the world, and some estimates place the number as low as 1,000.
We came very close to wiping out this marvelous species through unsustainable harvesting. On the East Coast, the sea mink was already extinct in the 1800s as a result of overhunting for the fur trade. Sea otters are tough, but they take several years to mature, usually have only one pup, and can live more than 20 years. Taken together those factors mean the species cannot recover quickly from a population decline.
Over the past century the worldwide population of sea otters has gradually increased, with an estimated 100,000 alive in the wild today. I am grateful sea otters are still around to remain on my top 10 list of most appealing mammals. When you see one, I suspect they will make your list, too.