How much does a sea otter weigh?

Many adult marine mammals gain and lose weight throughout the year depending on the water temperature, food availability and behavioral changes associated with breeding seasons. Here at the Seattle Aquarium we weigh our marine mammals at least twice a month in order to monitor their health. Unlike other marine mammals, sea otters do not have an insulating layer of blubber and instead rely on their dense fur and high metabolism to keep warm. Sea otter fur is the densest of any animal on earth with an average of 500,000 hairs per square inch. They live in water that ranges in temperature from 35-60°F, so in order to keep their body temperature at approximately 100°F, a sea otter needs to east approximately 25% of its body weight each day! For more interesting facts about our sea otter, go to

Can you guess how much Lootas weighs? Place your guess here and visit us April 6-8 for Marine Mammal Mania! Lootas will be weighed at 11:30am each day. Come see if you guessed correctly and for more information about the hands-on activities, special talks and demonstration during Marine Mammal Mania, go to!

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