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Some Things You ‘Otter’ Know!

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Conservation | Education | Mammals

Tuesday, March 11, 2008


They’re undeniably entertaining, extremely resourceful, and have the densest fur of any animal on the planet! What animal am I talking about? Why, the sea otter (Enhydra lutris), of course! Back in December, Hugh introduced our readers to our family of three Southern sea otters that call the Aquarium home: Brook, Charlie, and Summer. I’d like to share a little more with you about sea otters, as well as how you can help these endangered animals make their way down the long road to recovery!

A Brief History
Back before they were hunted almost to extinction, sea otters could be found in many areas of the Northern Pacific from Japan all the way over to Alaska and down through Baja California. Man discovered the luxurious fur coat of the sea otter and almost wiped them out completely during the eighteenth and nineteenth centuries. Fortunately, in 1911 the United States, Japan, Great Britain, and Russia signed the International Fur Seal Treaty, which made the sale of otter fur illegal. It is estimated that there were only about 1,000 – 2,000 animals left out of the original populations of several hundred thousand to more than a million! In California, the surviving Southern sea otter population consisted of only 20–30 animals. In 1972, sea otters were protected under the Marine Mammal Protection Act, and then in 1977 Southern sea otters were listed as a threatened species under the federal Endangered Species Act.

Fur and Food
Sea otters don’t have a thick layer of blubber like most marine mammals, so they have to rely on other adaptations to stay warm. The first of these we’ll talk about (again) is that beautiful fur coat! Amazingly, sea otters can have up to one million hairs per square inch. That’s the equivalent of ten human heads of hair! They will blow air into their fur, which creates a warm, insulating layer that helps them maintain their body temperature. The otter’s skin will stay almost completely dry underneath. It is imperative the animal keeps it’s coat immaculately clean in order to be able to thermoregulate properly. That’s why a large part of a sea otter’s day is spent grooming and cleaning their coat.

Sea otters have an extremely fast metabolism, which is another way they maintain their body temperature. To fuel this metabolism, sea otters need to eat around 25% of their body weight every single day! For instance, a 100-pound sea otter would need to consume at least 25 pounds of food per day. These animals spend a large part of their day foraging for food, with their diet usually consisting of sea stars, sea urchins, clams, crabs, mussels, and whatever else they can get their paws on! They are extremely resourceful, even using rocks and shells as tools to aid them in breaking open the shells of their catch.

The Bad News: Sea Otters Are Still Threatened
Though sea otter populations are in the process of a very slow recovery, these animals still face numerous threats besides their natural predators. Sadly, humans pose the greatest threat to sea otters. Fertilizers and other contaminants are washed into the water from the land, containing chemicals and other things that can cause disease or death. Oil spills are extremely detrimental to otter populations because the oil coats the otter’s fur, making it impossible for the animal to stay warm. The otter ends up freezing to death or being poisoned from ingesting the oil while trying to clean its fur. Even animal waste (including flushed cat litter/feces) can contain parasites or bacteria that can cause illness and eventually death.

The Good News: We Can Help Sea Otters!
I hope you will join me in doing all we can to help sea otters. Even though their numbers are up slightly more than a few years ago, they’re still very vulnerable. Here are a few suggestions if you’d like to help:

  • Don’t over-fertilize or over-water your lawn, and limit or eliminate the use of pesticides.
  • Don’t flush cat feces or kitty litter! Domestic cats can carry the eggs of a parasite in their feces that can be fatal to sea otters. Even though the sewage may be treated, the eggs can still survive.
  • Clean up after your animals. Animal waste can cause disease, especially once it is washed into coastal waters.
  • Make sure you dispose of household chemicals and motor oil properly. Don’t pour chemicals down the sink or allow motor oil to be disposed of in a storm drain.
  • Support legislation protecting sea otter habitats, kelp forests, and marine preserves.
  • As always, reduce, re-use, and recycle!
  • Attention California residents! You can help sea otters when you file your state taxes. Just look for line 60, the CA Sea Otter Fund, and donate what you can. This fund supports the research and rehabilitation of California sea otters.

Thank you for reading, and for all you do for the oceans!

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