The river otter’s eyes and ears are located high on its head for surface swimming. A third eyelid, or nictitating membrane, protects the eye and allows the otter to see when swimming underwater. The otter’s ears and nostrils close underwater.

River otters have long, stiff and highly sensitive facial whiskers that aid in locating and capturing prey. The otters typically capture prey in their mouths but occasionally use their thumbs and forepaws to grasp and manipulate prey. Like other carnivores, their teeth are well adapted for grinding and crushing.