- Any of several kinds of crabs often found on rocky coasts, especially
- Hemigrapsus sexdentatus, a large-eyed marine crab found off the coast of New Zealand, the common rock crab
- Cancer irroratus, the Atlantic rock crab, a crab with large marginal teeth, found along the Atlantic coast of North America
- Romaleon antennarium, the Pacific rock crab of parts of the Pacific coast of North America.
- A red rock crab.