Wildlife on the Brink: Southern Sea Otter

SCIENTIFIC NAME: Enhydra lutris nereis

STATUS: Threatened

HABITAT: Coastal waters, particularly dense kelp forests

LIFE HISTORY: Must eat the equivalent of a quarter of total body weight per day to keep warm; dives up to 180 feet for food. Fur is the thickest of all animals: 100,000 hairs per cm2, or 800 million hairs on a large adult.

THREATS: Biological pollution; pesticide and chemical run-off; oil spills

FORMER RANGE: Northern California to Baja California

CURRENT POPULATION: 2,200

These clever creatures bash or pry open their shellfish suppers with small rocks; they are one of the few mammals known to use tools. Otters are a classic "keystone species"—the health of the California coast's otter population is an excellent indicator of the marine ecosystem's overall health. By eating shellfish that nibble on kelp, sea otters help maintain kelp forests, which provide habitat and nourishment for a plenitude of fish and invertebrates.

Sea otters have the thickest fur in the animal kingdom, a trait that got them into trouble in the 18th and 19th centuries, when fur-trappers nearly hunted them to extinction. In California, about 2,200 southern sea otters remain in the coastal waters off the state's central coast.

Water pollution, particularly the discharge of disease-causing bacteria and viruses into coastal waters, appears to be taking a toll on the otter, which has been on the endangered species list since 1977. NRDC is working to ensure that a wastewater treatment plant in San Luis Obispo County upgrades its treatment of bacterial pollution in Morro Bay, a vital part of sea otter habitat.

Photo: southern sea otter © NOAA/Dept. of Commerce