An otter is a playful, sleek mammal that spends most of its life in or near water. Otters have thick, waterproof fur, webbed feet for swimming, and long, muscular tails they use like rudders to steer through rivers, lakes, and coastal waters.

These clever animals are famous for using tools: sea otters float on their backs and crack open shellfish by smashing them against rocks balanced on their bellies. They're excellent swimmers, able to hold their breath underwater for several minutes while hunting fish, crabs, and other prey. River otters slide down muddy banks into the water, sometimes just for fun, making them one of nature's most entertaining creatures to watch.

Otters live in family groups and communicate with chirps, whistles, and squeaks. A mother otter is fiercely protective of her pups, teaching them to swim and hunt. While resting, otters sometimes hold paws with family members so they don't drift apart.

Different species live in different places: river otters inhabit freshwater streams across North America, while sea otters live along the Pacific coast. Their dense fur, once prized by hunters, nearly drove them to extinction, but conservation efforts have helped many otter populations recover.