You’re probably familiar with the red-bellied piranha, which you can see in the Amazon River.
Behind their large, curled lips on their blunt-shaped heads hide a single row of teeth on both their top and bottom jaws. These fish have remarkable teeth described as tricuspid; a molar with three points, or cusps. Like sharks, they constantly lose and regrow their teeth throughout their entire lives. These serrated teeth are designed in a way to allow perfect interlocking with one another, and with the jaw.
The red-bellied piranha has incredible force to bite down and shear food. It can exert a bite force equivalent to thirty times their body weight, topping any living animal on earth!
A related species under the same family, the black piranha (Serrasalmus rhombeus), outmatches even the tyrannosaurus rex when it comes to bite force to body weight equivalency. If looking at the numbers here, the black piranha has a bite force of 320 Newtons, three times greater than that of the American Alligator!
This is due to piranhas having greater sized jaw muscles to body ratio with a specialized jaw lever closing system. Piranhas top even crocodiles, sharks, hyenas, and the prehistoric megalodon.
Living piranhas today give off the impression that they chase after and eat large animals swimming in the Amazon waters. However, it is quite the contrary. The red-bellied piranha hunt in groups for safety, also called a shoaling, and typically nip off the fins and tails of other fish, rather than consuming them whole.
They are more likely to go after and rip flesh off already deceased or weakened animals. What may surprise many is that they are omnivores, readying at the opportunity to swim over to the sound of fallen nuts in the water that their jaws are specially adapted to break open, or even graze off vegetation on rocky surfaces.