Fishermen call the animals “thumb-splitters” — at least one man has had a finger amputated after a mantis shrimp strike — and a blow from the crustacean’s truncheon can crack a pane of stock aquarium glass... The mantis shrimp, only distantly related to the species you would find covered in tempura batter, come in two types, which marine biologists divide into “spearers” or “smashers.” The spearers impale prey with a javelin strike of a pointed claw, whereas the smashers use their fist-like appendages to pop the shells of their food. Smashers, and their shrimply hammers — technically known as dactyl...