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Food habits vary significantly according to species, location, and season.
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River otters' diets consist largely of crayfishes, crabs, and other aquatic invertebrates; fishes; and frogs. Despite concern that otters compete with game fishers, the fishes that otters consume are mainly non-game species. Otters may also occasionally prey on birds, rabbits, and rodents. |
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Giant otters eat mainly fishes and crabs. |
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Cape clawless and Asian small-clawed otters feed mainly on crabs and other crustaceans, molluscs, and frogs. Fish are relatively insignificant in their diets. Congo clawless otters probably feed on fairly soft prey items such as small land vertebrates, frogs, and eggs. |
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A sea otter's diet consists mainly of slow-moving fishes and marine invertebrates including crabs, sea urchins, abalones, clams, mussels, and snails. Food preferences vary among individuals. |
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Two or more otter species occupying the same geographical area usually have different food habits.
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In Thailand, the ranges of at least three otter species overlap. Of these, scientists have determined that the Asian small-clawed otter eats mainly crabs, the smooth otter relies primarily on large fishes, and the Eurasian otter feeds mainly on smaller fishes and amphibians. |
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In South America, the neotropical otter preys on small fishes, while the giant otter preys on larger species. |
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In some areas where two or more species overlap, one may be a marine species and the other a freshwater species, such as the marine and southern otters of southern South America. |
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In Monterey Bay, California, researchers found that each sea otter tends to specialize in only a few types of the more than 50 available invertebrates. This behavior may reduce competition in the California population. |
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