The stomach contents of an adult shot on a Malaysian riverbank consisted only of fish. They have been observed to wash objects, raccoon-style. Live fish are readily taken, with full submergence of the head, and the fish were usually carried at least 2 m away, suggesting a feeding strategy to avoid letting aquatic prey escape back into water. Captive specimens show much greater interest in potential prey in the water than on dry land, suggesting a strong preference for riverine hunting in their natural habitat. Their morphological specializations suggest that their diet is mostly composed of fish, but they are reported to hunt for frogs, and are thought to catch crustaceans. They also catch rats and chickens.