Piranhas have one of the strongest bites found in bony fishes. Relative to body mass, the black piranha (Serrasalmus rhombeus) produces one of the most forceful bites measured in vertebrates.
This extremely powerful and dangerous bite is generated by large jaw muscles (adductor mandibulae) that are attached closely to the tip of the jaw, conferring the piranha with a mechanical advantage that favors force production over bite speed. Strong jaws combined with finely serrated teeth make them adept at tearing flesh. Piranhas are indigenous to the Amazon basin, in the Orinoco, in rivers of the Guianas, in the Paraguay–Paraná, and the São Francisco River systems.