The Lowdown
The sea otter (Enhydra lutris) is a keystone marine mammal that survives in freezing North Pacific waters without a single ounce of blubber. Instead, it relies on the densest fur coat of any animal on Earth—boasting nearly one million hairs per square inch. This double-layered coat traps a microscopic barrier of dry air against their skin, keeping them completely dry even while diving forty meters deep.
Sea otters are among the few non-primate mammals known to use tools. Floating on their backs in giant offshore kelp forests, they balance a flat rock on their chest as an anvil, smashing hard-shelled clams and sea urchins against it at speeds of up to three strikes per second. Each otter possesses a favorite rock, which it stores in a loose pouch of skin under its front armpit.
Biological Fact: Sea otters hold hands while sleeping in floating groups called rafts to prevent the ocean currents from drifting them apart.
By devouring hundreds of grazing sea urchins each day, sea otters prevent urchin barrens from destroying underwater kelp forests. These towering kelp forests absorb massive quantities of carbon dioxide and provide critical nurseries for thousands of fish species.
