Ondatra zibethicus (Common Muskrat) are often considered herbivores; however, they also eat animal matter, especially mussels, which comprise a considerable part of their diet in some populations. Common Muskrats also feed on crayfish (Astacoidea), although such behavior is poorly documented. On 21 April 2022, we observed a Common Muskrat repeatedly catching crayfish (Cambaridae) and carrying them to its den. The site in the Coldwater River National Wildlife Refuge, Quitman County, MS, consisted of a ditch with a water-control structure on the edge of a waterfowl impoundment being dewatered. The consumption of crayfish by a Common Muskrat during a time when vegetation was presumably less available has important ramifications for the management of both species.