Piranha teeth aren't all that unique

摘要

When it comes to scary teeth, piranhas' are among the most fearsome. The razor-sharp chompers strip prey's flesh with the ease of a butcher's knife.In a process that may avoid dulling, the fish lose all teeth on one side of the mouth at once, with a fresh set growing in five days later. The same then happens on the other side of the jaw months later. Scientists thought that trait was unique to piranhas, and evolved as the fish adapted to a diet of scales, fins and flesh.