Yes, piranhas are indigenous to the Amazon River basin and are one of its most famous inhabitants. Contrary to their Hollywood reputation as bloodthirsty monsters, most of the 30 to 60 species of piranha are actually omnivorous scavengers that primarily eat fish, insects, seeds, and fruit. The red-bellied piranha is the species most commonly associated with aggressive behavior, but even they typically only bite humans if they feel threatened or if water levels are extremely low during the dry season, leading to food scarcity. In many Amazonian communities, piranhas are a vital part of the local diet and are considered a cleaner food source than bottom-feeding catfish. Scientists have discovered that their "swarming" behavior is actually a defensive strategy to protect themselves from predators like caimans, pink river dolphins, and various birds. While they do possess razor-sharp interlocking teeth and incredibly powerful jaw muscles, they generally coexist peacefully with humans who swim in the river daily.