There are 11 species of river otter, including the Eurasian river otter (Lutra lutra), the North American
river otter (Lutra canadensis), the southern river otter (Lutra provocax), and the smooth otter (Lutra perspicillata). Often confused with European mink, the river otter is heavier, with a broader face and a tail that is stout at the base, becoming flatter and more tapered toward the end. River otters are most prevalent in Eurasia and North America, although a few species are found in Central and South America, as well as in limited areas of Africa and Southeast Asia.
River otters usually live near rivers, although some species live near flooded areas, lakes, brackish water, and on coastal islands. When the food supply runs low, river otters will move away from their native waters to hunt. They prefer to move via water but will travel on land if they must. These otters usually hunt at night, staying underwater for up to eight minutes at a time. Normally, the adults hunt alone, but mothers will hunt with their young for a significant period of time after they are born. Traveling long distances during a single night's hunt, they conceal themselves in the day in reeds and other vegetation before hunting again the next night. In a few days, these otters return to their home waters. During the winter, river otters slip through cracks in ice to hunt, sometimes surfacing through the hole to breathe. River otters eat fish, muskrats, and aquatic birds.
The female river otters bear its young in a burrow between April and June. Born with their eyes closed, the young nurse for about four months, opening their eyes about one month after birth. They grow to adult size in two years.
Grooming is very important to river otters. However, unlike many other mammals, river otters do not nibble their coats looking for insects. Instead, like sea otters, they tend to groom themselves with the goal of drying out their fur to keep it waterproof. They do this by rolling and squirming on dry land or rubbing against trees.