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The Surprisingly Deadly Mantis Shrimp

Mantis shrimp, particularly the more colorful varieties like the peacock mantis, are popular subjects for underwater photographers and are welcome sights on dives throughout the Indian and Pacific Oceans. Usually seen in rock crevices or in the burrows that they create for themselves in the sea bed, mantis shrimp are exceptionally territorial. They are relatively small crustaceans, with the largest of the 400 species currently known only measuring around twelve inches in length. However, the mantis shrimp’s small size is by no means reflective of its identity both as a lethal predator and as one of the most fascinating of all marine creatures. There are many unique aspects about this shrimp, one of the most significant of which is how they catch and kill their prey.

Peacock Mantis Shrimp by Jens Petersen

Peacock Mantis Shrimp by Jens Petersen

There are two kinds of mantis shrimp; those equipped with spear-like appendages that they use to stab their prey, and those more advanced specimens that possess a developed club for smashing their food. These clubs are exceptionally powerful, enabling the mantis shrimp to strike at speeds of over 50 miles per hour, and pack a punch with the acceleration of a .22 caliber bullet. The power behind the strike is so extreme that larger species of mantis shrimp are able to shatter aquarium glass with a single blow, and are consequently rarely kept in captivity. The victim of a mantis shrimp’s blow is struck with a staggering force of approximately 1,500 newtons.

The devastating effect of the mantis shrimp’s club is compounded by the cavitational bubbles caused as a result of the sheer speed with which the animal strikes. The bubbles create a kind of shockwave that follows directly in the wake of the initial blow. The primary prey of the mantis shrimp species equipped with this incredible club include crabs and mollusks, while the spearing mantis favor fish due to their softer flesh. Amazingly, despite the level of impact that the club absorbs each time it strikes, a mantis shrimp can punch 50,000 times between molts without sustaining any damage to the club. Scientists are attempting to replicate this level of resilience by modeling military body armor on the design of the mantis shrimp’s cell structure.

Mantis eyes by Bob Whorton

Mantis eyes by Bob Whorton

For many years, experts believed that mantis shrimp could detect colors that the human brain is unable to process, due to the fact that mantis shrimp possess 16 different photoreceptors in their eyes, in comparison to the three possessed by humans. However, recent studies suggest that in reality, mantis shrimp encode color in a way that is completely unique to all other animals. For example, when the human brain looks at an object, it can determine the color by using its three color receptors (red, blue and green) in conjunction. Our brain understands that an object is yellow, for instance, because of the level of responsiveness it triggers in each of our receptors. A mantis shrimp, on the other hand, uses its sixteen receptors to pick up sixteen colors- they do not work in conjunction to allow the shrimp’s brain to process the mid-hues in between.

However, while the mantis shrimp may not inhabit as technicolor a world as we once thought, its eyes are still among the most complex in the animal kingdom. They are capable of moving independently of one another, and can detect polarized light, multispectral images and ultraviolet light. Certain species can even detect circularly polarized light, an ability that scientists are trying to harness in order to apply it to the next evolutionary stage in high definition technology. Why the mantis shrimp needs such advanced eyesight is uncertain, although it seems likely to pertain to mating and hunting advantages. Whatever the reason, the mantis shrimp’s miraculous vision combined with its incredible hunting technique make it one of the deadliest (and most intriguing) creatures in the sea.