Most common shrimp species lack mouthparts capable of biting or injuring humans; while they might investigate or “pinch” with small appendages, these actions are generally harmless. However, some specialized marine crustaceans, often called shrimp, possess unique mechanisms that can cause significant injury.
Shrimp Mouthparts and Feeding
A typical shrimp’s feeding apparatus processes small food particles, not large objects. Their mouthparts include mandibles for cutting and grinding, maxillae for food manipulation and water circulation, and maxillipeds (often called “jaw feet”) that aid in handling food.
Shrimp are primarily omnivorous scavengers, consuming algae, decaying plant matter, biofilm, and small organisms. They use their legs and specialized mouthparts to sift through sediment, filter water, or nibble on food items. Their feeding behavior, which breaks down food into fine particles, means their mouthparts are not structured for biting human skin. While some larger shrimp might pinch, it typically feels like a minor sensation and does not cause injury.
Species Capable of Causing Injury
Certain species, colloquially called “shrimp,” possess specialized appendages that can inflict considerable harm. Mantis shrimp (order Stomatopoda) are known for their formidable raptorial claws, categorized as “spearers” (sharp, barbed claws for impaling prey) or “smashers” (club-like appendages for powerful blows).
A smasher mantis shrimp can strike with remarkable speed, reaching velocities of up to 23 meters per second, generating forces of around 1,500 Newtons. This impact can cause blunt force trauma, leading to severe bruising, deep lacerations, or even fractures, particularly to smaller bones like fingers. The force is so substantial that some larger species can shatter aquarium glass. These strikes also create cavitation bubbles, which collapse with additional shockwaves and heat, further damaging prey.
Pistol shrimp, also known as snapping shrimp, employ a different, yet equally impressive, mechanism for stunning prey. They possess an oversized claw that, when rapidly snapped shut, creates a high-velocity water jet. This action forms a cavitation bubble that, upon imploding, generates a powerful shockwave. The implosion produces a loud “snap” sound, reaching up to 218 decibels, and briefly generates temperatures comparable to the surface of the sun within the bubble. While the primary effect is stunning prey and not directly breaking skin, the shockwave can cause temporary hearing damage if a person is underwater nearby.
Encountering Potentially Harmful Shrimp
Encounters with mantis or pistol shrimp resulting in injury are uncommon, often occurring when individuals handle them carelessly or when they are present in fishing nets. Fishermen sometimes refer to mantis shrimp as “thumb splitters” due to their capacity to inflict painful wounds. Observing marine life from a distance is the most effective way to avoid potential harm from these creatures. Avoiding direct contact and handling unknown marine animals are key precautions.
If injured by a mantis shrimp, prompt first aid is advisable. The affected area should be thoroughly cleaned with soap and water to prevent infection. If bleeding is present, applying direct pressure with a clean cloth can help control it. While most injuries are not life-threatening, deep wounds, uncontrollable bleeding, or suspected fractures necessitate immediate medical attention.