Lying on its back, the otter places the rock on its stomach and pounds the shelled animal against it until it cracks open.
The sea otter is one of the few animals to use tools for hunting and eating. It dives into the water and uses a rock to dislodge molluscs, then swims to the surface with the rock under its arm and the prey in its forepaw. Lying on its back, the otter places the rock on its stomach and pounds the shelled animal against it until it cracks open. © Marshal Hedin/ Flickr (CC BY-SA 2.0).