Do Sea Otters Really Hold Hands While They Sleep?

Picture a calm cove on the coast of California in the late afternoon. Dozens of furry heads bob among the golden-brown kelp, and one by one the sea otters roll onto their backs, fold their paws on their chests and settle down for a nap on the gently rocking water. It looks like the cosiest bedroom in the ocean, and in a way it is.

The picture everyone shares

You have almost certainly seen the photo, or the video, or the greeting card: two sea otters asleep side by side, holding paws so that they do not drift apart. The most famous clip was filmed at the Vancouver Aquarium in Canada and went viral in 2007, and ever since, hand-holding has been treated as the thing sea otters do. The idea is so charming that it has become the whole story of how otters sleep.

What people often get wrong

The otters in that video really were holding paws, so the picture is not fake. What is wrong is the idea that it is normal. According to Discover Magazine, it is quite rare to see sea otters holding paws, especially in the wild, and researchers have wondered whether the habit is simply a quirk of certain individual otters rather than something the whole species does. A cuddly exception turned into the rule because it made such a lovely video.

How otters really stay put

Wild sea otters have a more practical trick, and it grows all around them. NOAA's Ocean Today describes a female otter lying on her back, laying a piece of kelp across her belly before a nap, so that it keeps her in place and she does not drift off to sea. NOAA's National Marine Sanctuaries say the same: sea otters often wrap themselves in kelp to rest without drifting away. The long, rubbery seaweed is rooted to the sea floor, so an otter tucked into it is moored like a small, whiskery boat.

Otters also rest together in groups called rafts, often made up of only males or only females. Discover Magazine reports that a raft can hold fewer than ten otters or more than a hundred, and that is where the real togetherness happens: not two paws linked, but many bodies floating close in the same patch of kelp.

Why a nap takes so much care

Sea otters have no layer of blubber like seals or whales. Instead they rely on their fur, which the Monterey Bay Aquarium describes as the densest of any marine mammal, and on constant grooming that traps warm air in it. Ocean Today even notes a resting otter holding her feet out of the water to keep them warm. With so much energy going into staying warm, floating calmly and safely in one place is worth arranging properly.

• 1 million+ hairs on a single square inch of sea otter fur
• Up to 8 h spent grooming in a day
• 20-30% of its own body weight eaten in food every day

So the next time the hand-holding picture comes round, enjoy it: it is real, just rare. The everyday version is less romantic and rather clever, an otter wrapped in seaweed like a sleeping bag, bobbing on the tide and going nowhere at all.