How do sea otters use stones to open clams?

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Two wild horses graze on tall grass in the open prairie of Theodore Roosevelt National Park, with rolling badlands visible in the background. — Feeding behaviour Wild horses graze in the Badlands of North Dakota.

Sea otters exhibit remarkable tool use when feeding. To open hard-shelled prey such as clams, crabs, and other shellfish, the sea otter floats on its back and balances a stone on its chest. It then smashes the mollusk against the stone to break the shell and access the meat inside. This behavior allows them to efficiently consume prey that would otherwise be difficult to open.123