1. Fish: Fish form a significant portion of an otter's diet. They are highly skilled at hunting and catching fish underwater. Some fish that otters commonly prey upon include trout, salmon, catfish, bass, and carp.
2. Crustaceans: Crabs, shrimp, crayfish, and lobster are favorite crustacean foods for otters. They have strong claws that help them crack open the hard shells of these invertebrates.
3. Mollusks: Mussels, clams, and abalone are mollusk species that otters often feed on. They have keen senses that allow them to locate these mollusks beneath the water's surface.
4. Amphibians: Otters sometimes hunt for frogs and salamanders, particularly during the breeding season when these amphibians are abundant near water bodies.
5. Birds: Depending on the habitat, otters may also consume birds, including ducklings and injured or nesting birds found along the shoreline.
6. Small Mammals: Some species of otters may occasionally hunt and eat rodents, such as mice and voles, if fish and other aquatic prey are scarce.
It's important to note that different otter species may have specialized food preferences based on their environment and the availability of prey. Some otters may be generalist feeders that consume a wide variety of food items, while others may be more specialized in their diet. Additionally, their food choices can vary based on seasonal variations in prey abundance.