Sea otters may just look like cuddly little creatures happily bobbing around the water with a fishy meal on their bellies, but all that cuteness is actually very serious business. Known as a keystone species, sea otters are vital to the health of their kelp forests homes. Kelp helps keep our air clean, it protects our shores from storm surge, and it provides for a variety of marine life. Unfortunately, it’s a favorite food of sea urchins, which decimate the forests leaving underwater wastelands in their wake.

Enter the otters! These eating machines consume up to 25% of their body weight to stay warm in chilly Pacific waters—and they love to snack on sea urchins. That helps keep the populations of these spiny pests in check. In fact, when sea otter populations plummeted in the 1700 and 1800s—they were once hunted almost to extinction for their beautiful pelts—kelp forests suffered greatly. Luckily, sea otter hunting was banned internationally in 1911, and otter populations slowly began to recover.

Today, you’ll find them where kelp forests flourish, floating on their backs and wrapping themselves and their pups in the giant seaweed to anchor in one spot while they eat, groom, or rest. Sometimes rafts of otters, or groups of up to 100, will even link arms or hold paws as they bob together on their backs in the kelp.

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Cool Tools Sea otters are one of the very few mammal species to use tools. After diving as deep as 300 feet to forage on the sea floor for mollusks, crustaceans, and sea urchins, sea otters smash the hard shells against stones—anvil style—to crack them open and get their meal.	Set in Stone Otters are particular about their tools—once they find a good stone, they’ve been known to keep it for life. They stash their favorite in a pouch of loose skin under their forearm where they also store their prey while diving before bringing their finds to the surface to eat.
Good Hair Day Unlike other cold-water creatures, otters don’t have blubber to stay warm. Instead, they have the thickest pelt of any mammal—up to a million hairs per square inch—that traps air and seals out the water. When not eating or resting, sea otters groom obsessively for better insulation.	Practice Makes Perfect Sea otters can “juggle”—rolling small stones from arm to arm and patting them into the air. While nobody’s sure exactly why they do this, some scientists think it’s a fun way to practice manipulating the tools they need to crack open their dinner. Watch it in action!