Sea otters really do have built-in pockets. Beneath each forearm is a fold of loose skin that works like a pouch. An otter can tuck food inside while diving, leaving its paws free to gather more. It may also carry a rock there—useful when dinner comes in a shell.
A pocket for the catch
Imagine trying to collect clams underwater while holding everything you’ve already found. Sea otters have a practical solution: they slip their catch into those underarm folds and keep searching. The pockets aren’t separate bags or openings in the skin. They’re loose flaps tucked close to the body, easy to overlook beneath a thick coat of fur.
Once an otter surfaces, it floats on its back and uses its chest like a table. A clam or mussel may need more work before it can be eaten. As the Monterey Bay Aquarium explains, an otter can use a rock to crack open hard-shelled prey. That makes an underarm pocket a convenient place to carry both lunch and a tool.
Small detail, clever design
These pockets help an otter make the most of a dive, but they’re only one part of its feeding routine. Agile paws gather prey; the pouch holds the catch; and, when needed, a rock helps open the meal at the surface. NOAA’s sea otter anatomy guide describes the loose skin beneath each forearm and its role in carrying food and rocks.
It’s a wonderfully simple adaptation. Next time you see a sea otter floating with something on its chest, remember that it may have brought its meal up in an armpit pocket. For more surprising wildlife details, explore these animal facts.