A Eurasian river otter mother relaxes with with her two seven-month-old cubs on a shoreline in Shetland, U.K.
The charismatic otter, a member of the weasel family, is found on every continent except Australia and Antarctica. Most are small, with short ears and noses, elongated bodies, long tails, and soft, dense fur.
There are 13 species in total, ranging from the small-clawed otter to the giant otter. Though most live in freshwater rivers, lakes, and wetlands, the sea otter and the smaller marine otter are found in the Pacific Ocean.
Webbed feet and powerful tails, which act like rudders, make otters strong swimmers. Their nostrils and ears close to keep water out, and waterproof fur keeps them warm. They must carefully groom their fur and furry undercoat to keep them clean and sealed off to water, because they’re