What Do River Otters Eat?

By Ethan Shaw
Otters will consume prey in the water or sometimes haul it ashore.

The North American river otter (Lontra canadensis) is a semiaquatic mustelid -- a member of the weasel family -- native to a large swath of the United States and Canada, as well as northwestern Mexico. Social, playful and charismatic, river otters are also formidable hunters at or near the top of the freshwater and coastal food chain wherever they’re found. They feed on a very wide range of prey, primarily fish and crustaceans.

Fish as Prey

Fish represent a foundational component of the river otter's diet. Otters generally are opportunistic fish-eaters, most often nabbing slower-swimming species -- especially bottom dwellers -- and impaired individuals. Commonly eaten fish include perch, suckers, sculpin and catfish.

Other Prey

River otters also heavily favor crayfish in many areas. Other typical freshwater prey includes frogs, turtles, waterfowl and small mammals. Otters utilizing coastal marine habitats often snatch crabs and molluscs. In the Southeast, otters occasionally eat young alligators -- normally hatchlings, although a photographer in Florida captured an ambitious otter dispatching a 1.5-meter (5-foot) juvenile gator.

Comparison with Other Otters

The North American river otter essentially eats any animal it can catch and overpower, similar to the dozen other species of freshwater otter found elsewhere in the world. The 2-meter-long (7-foot-long) giant otter of South America, biggest of all, sometimes tackles even caimans and anacondas, particularly when hunting in groups.

About the Author

Ethan Shaw is a writer and naturalist living in Oregon. He has written extensively on outdoor recreation, ecology and earth science for outlets such as Backpacker Magazine, the Bureau of Land Management and Atlas Obscura. Shaw holds a Bachelor of Science in wildlife ecology and a graduate certificate in geographic information systems from the University of Wisconsin.