Otters live in both freshwater and seawater and are found everywhere in the world with the exception of Antarctica and Australia. They live on land in "holts," close to shallow water where they feed on fish, mussels, urchins and clams in the sea and small reptiles on land. River otters live along the banks of rivers and lakes, never farther than a stone's throw from water.
Otters move depending on the available food and shelter of a specific region. They require both land that has adequate shelter to build a habitat to raise young otters and water that isn't densely populated.
Otters are travelers and can traverse long distances over land or by sea. They frequently set out to explore for food and to socialize but always return to their home range, an area that can reach up to 10 square miles.
River otters have territories that are protected from those of the same sex. A male otter's territory can overlap with a female otter's, but no two territories of otters of the same sex can cross.
In California, river otters live in streams, creeks, rivers, marshes, reservoirs and canals of the San Francisco Bay watershed.
Otters also make their habitat on land in empty beaver lodges or burrows that other creatures have abandoned.