River otters are renowned for playing: they roll and tumble through the water, build waterslides of mud or snow on riverbanks, and chase each other with evident glee. It takes a lot of energy to have so much fun, though, so when it’s time to hunt, these graceful animals are all business.
River otters are opportunists when it comes to feeding. Their high metabolic rate fuels a hyper-kinetic lifestyle, but also requires them to eat many times each day. Otters hunt wherever there is food to be found: in freshwater, in saltwater, and on land. They eat a wide array of prey animals and the occasional plant. Otters generally prefer fish, but have been known to take crabs, frogs, mussels, clams, rabbits, sea urchins, crayfish, snakes, insects, earthworms, muskrats, turtles, and even birds on rare occasions. They can’t afford to be fussy eaters.
How do river otters capture these diverse prey items? They are supremely well-adapted to that task. In the water, otters are fast and incredibly maneuverable, able to out-swim even such swift fish as trout and salmon. The otter’s sleek, streamlined body and webbed feet give it a remarkable hydrodynamic advantage. They can also remain submerged for up to eight minutes before coming up to breathe. River otters use their sharp, cone-shaped teeth to capture prey rather than using their hands, as sea otters do. Other useful adaptations include built in “goggles,” special lenses on their eyes that help the otters to see clearly underwater, and long, very sensitive whiskers that are useful for finding prey in dark or murky water.
They are no slouches on land, either; a sufficiently motivated river otter can run at speeds up to 18 miles an hour! The inquisitive creatures are adept at rooting out edible morsels such as snails and worms from riverbanks and forest floors. Unusually for a semi-aquatic animal, they have a well-developed sense of smell.
When an otter catches a small creature (no more than 5-6 inches long), it eats the prey on the spot. They can’t handle anything larger than that in the water- big food items will be taken to dry land to be consumed. River otters have no use for left-overs; if they capture an animal that is too large to eat all at once, they abandon the remains. Other scavenging birds and mammals then benefit from the otter’s hunting prowess.
Playing all day takes a lot of energy. River otters use their elegant hunting adaptations such as speed, agility, and sharp senses to fuel a lifetime of fun!