Mantis shrimps are distant cousins of lobsters and shrimps. More than 450 species live in warmer oceans throughout the world and prey on a variety of species including fish, snails, and crabs.
They have specialized limbs and claws for capturing their prey. Some species—the smashers—have legs with what looks like a club at the end, used to bash prey; other species—the spearers—have spiny legs, perfect for stabbing prey. These legs can strike prey extremely quickly by using a spring and latch mechanism. As one leg muscle contracts and stores mechanical energy by deforming the exoskeleton, a second muscle holds the latch in place to prevent the leg from moving. When ready, a third muscle releases the latch, and the leg springs out.
The movement of the leg results in a pressure change that causes bubbles to form in the surrounding water. These bubbles quickly collapse, releasing energy—a process called cavitation. Researchers think cavitation helps mantis shrimp break apart prey such as the unfortunate snail (pictured here).
Roy Caldwell, PhD., Department of Integrative Biology, University of California Berkeley