“So is this great and wide sea, wherein are things creeping innumerable, both small and great beasts” (Psalm 104:25).
If you enjoy keeping tropical fish, the Mantis shrimp is one creature you may not want to keep in your aquarium. While this creature is related to common shrimp, it has a very unusual and specialized feature.
In the wild, if the Mantis shrimp finds a tasty snail, it cocks its spring-loaded forearm and shatters the snail’s shell. The forearm has moved through the water at 50 miles per hour – so fast that it causes cavitation as well as heat and a flash of light as the bubbles collapse. And, yes, the Mantis shrimp can break the glass walls of an aquarium! To do this, the shrimp must generate over two-hundred thousand watts of power per pound of muscle, something no other muscle can do. The shrimp accomplishes this seemingly impossible task by storing the energy generated by the muscles. The shrimp first locks the arm and then contracts its muscles. The energy stored in this way would damage the arm if it weren’t for a very clever spring design. This saddle-shaped spring can accumulate enormous quantities of energy without breaking as it compresses. When the shrimp is ready to strike, it simply releases the spring.
The Mantis shrimp’s forearm is only an effective working unit when all of its specialized parts are working together. It is difficult to imagine how it could have evolved.