The California mantis shrimp (shown here) produces sounds by vibrating its carapace, the hard, protective shell that covers the back of the animal. Image credit: Roy Caldwell, University of California, Berkeley (http://ib.berkeley.edu/labs/caldwell/)
Mantis shrimp, also known as stomatopods, are benthic marine crustaceans. There are approximately 350 species of mantis shrimp, ranging in size from 2 to 30 cm (approximately 1 to 12in). Most are found in shallow, tropical or subtropical waters, living in cracks or crevices, among rubble, or in borrows that they build in the sand or mud.
Mantis shrimp are aggressive predators that feed primarily on fish, crabs, snails, and shrimp. Their eyes are stalked and mobile, providing excellent eyesight. Mantis shrimp also use a pair of specialized mouthparts, the raptorial appendages, to catch their prey. Different methods of prey capture separate mantis shrimp into two groups: the spearers and the smashers. Spearers use sharp appendages to spear and/or slice their prey. Their raptorial appendages have spines that are used to catch and stab prey, usually unsuspecting fish. Smashers use a large, club-like appendage to crush prey with shells or hard exoskeletons, such as snails and crabs.
Mantis shrimp are aggressive predators that use a pair of specialized appendages to catch their prey. Different methods of prey capture separate mantis shrimp into two groups: the “spearers” and the “smashers”. The raptorial appendage of a “spearer”, the zebra mantis shrimp (Lysiosquillina maculata), is shown on the left. The specialized appendage of a “smasher”, the peacock mantis shrimp (Odontodactylus scyllarus), is shown on the right. Image courtesy of Dr. Sheila Patek, Duke University (https://pateklab.biology.duke.edu)
Mantis shrimp predatory strikes happen quickly. In the peacock mantis shrimp, Odontodactylus scyllarus, which uses a hammer-like appendage to smash open the shells of its prey, predatory strikes have been known to reach a maximum speed of 23 m/s (75 ft/s). As a result of this fast, smashing motion, bubbles form and then immediately collapse (cavitation), a process that produces heat, light, and sound.
The California mantis shrimp, Hemisquilla californiensis, produces sounds by vibrating its carapace, similar to the American lobster. The low frequency rumbles of the mantis shrimp are approximately 167 Hz and last approximately 0.2 s. Although each animal produces its own distinct rumble sound, scientists have recorded multiple individuals in an area producing rumble sounds at the same time. Acoustic activity is also high during dawn and dusk, a time when the animals are feeding or guarding their burrows.