Mantis shrimp are marine crustaceans known for their powerful and rapid “punch” or strike. These creatures, typically 10 cm but sometimes growing up to 30 cm, possess specialized appendages that deliver one of the fastest movements in the animal kingdom. A common question is whether this formidable strike can inflict harm upon a human.
The Mantis Shrimp’s Striking Mechanism
The mantis shrimp’s striking power originates from a sophisticated biomechanical system within its raptorial appendages, specialized forelimbs used for hunting. There are two types: “smashers” with a club-like appendage and “spearers” with sharp, barbed forelimbs. Smashers, like the peacock mantis shrimp, use a dactyl club that can accelerate up to 23 meters per second (50 miles per hour) in water, comparable to a .22 caliber bullet. This speed is achieved through an elastic energy storage mechanism, where muscles compress and store energy in a spring, rapidly released by a latch.
The strike generates immense force, sometimes exceeding 1,500 newtons, over 2,500 times the shrimp’s own weight. As the club moves at high speeds, it creates cavitation. This involves a rapid drop in water pressure, causing vapor-filled bubbles to form. These bubbles then collapse with tremendous force, releasing energy as sound, light, and heat. This allows smashers to break open the shells of crabs, snails, and other hard-shelled prey.
Potential Injuries to Humans
A mantis shrimp’s strike can cause injury to humans. While rarely life-threatening, these injuries can be painful and may require medical attention. The type and severity of injury depend on the mantis shrimp species and the strike’s impact location. Smasher species’ blunt force trauma can result in severe bruising, deep tissue damage, or fractures, particularly to smaller bones. Their powerful strikes are capable of cracking quarter-inch aquarium glass.
Spearer mantis shrimp, with sharp, barbed appendages, can inflict deep lacerations and puncture wounds. These wounds can bleed heavily and carry an increased risk of infection, especially in the marine environment. Fishermen report painful injuries, including deep cuts, when handling these animals. Some injuries have been severe enough to necessitate professional medical care due to pain and bleeding.
Safety and Encountering Mantis Shrimp
Given their powerful strike capabilities, caution is advisable in areas where mantis shrimp might be present. Observe these animals from a safe distance and never attempt to handle them directly. Divers and snorkelers should remain aware of their surroundings, avoiding crevices or rocks where mantis shrimp often hide.
For those keeping mantis shrimp in aquariums, specialized precautions are necessary. These creatures can break aquarium glass, so robust tanks are recommended. If handling is unavoidable, such as during tank maintenance, wear thick protective gloves, though a strike can still be felt. Respecting their space and avoiding situations where they feel threatened minimizes injury risk.