Peacock Mantis Shrimp: a true marine breaker
Commonly known as Peacock Mantis Shrimp, Odontodactylus scyllarus (Stomatopoda - Odontodactylidae) could well be called the marine breaker, because it is a true biological hammer when it comes to breaking the shells of its lunch. These shrimps are renowned for their unusual method of breaking shells with brief, powerful strikes of their raptorial appendages.
It has been discovered that each strike of Odontodactylus scyllarus generates two brief, high-amplitude force peaks, typically 390–480 μs apart. Based on high-speed imaging, force measurements and acoustic analyses, it is evident that the first force peak is caused by the limb’s impact and the second force peak is due to the collapse of cavitation bubbles. Despite their small size, O. scyllarus can generate impact forces thousands of times their body weight. Furthermore, on average, cavitation peak forces are 50% of the limb’s impact force, although cavitation forces may exceed the limb impact forces by up to 280%.
The rapid succession of high peak forces used by mantis shrimp suggests that mantis shrimp use a potent combination of cavitation forces and extraordinarily high impact forces to fracture shells. The stomatopod’s hammer is fundamentally different from typical shell-crushing mechanisms such as fish jaws and lobster claws, and may have played an important and as yet unexamined role in the evolution of shell form.