Sea Otters Hold Hands While Sleeping So They Don't Drift Apart in Ocean Currents

Sea otters spend most of their lives at sea, sleeping, eating, and even giving birth without ever touching land. To stay together while floating asleep, they have evolved a behavior that is both practical and genuinely heartwarming: they hold paws.

A group of resting otters — called a "raft" — can include over 1,000 individuals. By holding paws (and sometimes wrapping themselves in kelp), they prevent the group from drifting apart in ocean currents during sleep.

More Than Cute Behavior

• Densest fur: Sea otters have the densest fur of any mammal — up to 1 million hairs per square inch (1 cm² of human hair = ~100 hairs)
• Tool use: Otters carry favorite rocks in armpit "pockets" for cracking shellfish, and many keep the same rock for life
• Calorie demands: They eat 25% of their body weight daily — the equivalent of an adult human eating 18 kg of food per day
• Vital ecosystem role: By eating sea urchins, sea otters keep urchin populations in check, allowing kelp forests to thrive

Mothers and Pups

A mother otter who needs to dive for food cannot bring her newborn pup along. She solves this by carefully wrapping her baby in strands of giant kelp — anchoring it like a buoy on a leash — and diving to feed. When she surfaces, she returns directly to her tethered baby, every time.

Mother otters also rub their pups' fur with their paws for hours each day to keep their dense coats waterproof — without this maintenance, baby otters would drown.