Sea otter
Depth: 10 m · Sunlight Zone
The sea otter uses tools: it lays a stone on its belly and smashes shells open on it. Its fur is the densest in the world and keeps it warm without any blubber. To sleep it holds paws with other otters so it does not drift away.
For scientists
The sea otter (Enhydra lutris) is a keystone species: by eating sea urchins it protects the kelp forests from being grazed bare. Its fur has up to a million hairs per square centimeter, because it has no insulating layer of blubber. It has a favorite tool, often a stone, which it keeps in a pouch of skin under its arm.
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