River otters have brown fur on the back with a paler underbelly. The lower jaw and throat are whitish. They have a head that looks flat on top but is otherwise rounded and supported by a short neck that is as wide as their skull. The body of a river otter is cylindrical and ends in a muscular and flexible tail that is thicker at the base than at the tip. They have short legs and webbed toes that allow them to thrive as swimmers. However, as aquatic mammals, they also have small ears and nostrils that can can be closed underwater, allowing them to hold their breath until they resurface.

• Otters belong to the weasel family.
• This is the only inland otter species in North America.
• They usually stay underwater for less than one minute but can stay underwater for six to eight minutes.
• River otters were legally trapped for fur up until 1976.