The two river otters chase one another underwater, looping and turning and tumbling. River otters are the Southwest's water acrobats. These graceful animals swim right side up, upside down, on their side, or any way they choose. River otters can undulate like fish, using their heavy tail as a rudder. They can execute sudden U-turns, dive as deep as 40 feet, and race one another.
River otters are gregarious animals, and are usually seen in pairs or family groups.
River otters are made for water. Their short, strong legs end in webbed toes for better propulsion. Nostrils and ears that close underwater help river otters remain submerged for several minutes. Their dense coat of oily underfur keeps them warm even in near-freezing water. River otters are predators.