What Happens When You Fall Into A Piranha Infested Water?

You’re looking at the Amazon River when, suddenly, you slip and fall. Small, sharp-toothed fish swim swiftly in the quickly approaching water. So, are you in trouble? Will your fall cause a deadly frenzy? To predict what might happen, let’s explore what we know about these fish. There are over 30 types of piranhas.
They all live in the fresh waters of South America and have one row of sharp, hooked teeth on each jaw.
They use their teeth in different ways. Many eat a variety of foods such as insects, small shellfish, worms, and fish, along with fruits, seeds, and plants. Some, like red-bellied piranhas, both hunt and scavenge. And others, like wimple piranhas, mainly eat other fish’s scales. Species like red-eye piranhas tend to be loners, while red-bellied piranhas swim in groups of 10 to 100. Red-bellied piranhas are often shown as aggressive and are widely believed to be so. However, their reputation for rapacious pack hunting is misinformed.

It’s believed that the main advantage of living in groups isn’t working together to hunt, but instead staying safe from predators, which they have many of. Bigger, older red-bellied piranhas usually stay in the middle of the group, where it’s safest. Scientists have noticed that red-bellied piranhas in smaller groups breathe faster, probably because they’re more nervous. They also talk to each other.

They make quick movements with special muscles near their swim bladders, making repeated sounds like “barks” when they’re challenging each other or caught. They make thumping sounds when they’re circling each other aggressively, fighting, or competing for food. And when things get more intense, they chase each other while snapping their jaws. Scientists think they have more sounds they use, maybe even for mating. But when do red-bellied piranhas attack people? Well, it seems to happen mostly when they’re being touched, when food spills into the water, when people clean fish, or when people bother them while they're mating or guarding their eggs during the wet season. Hunger might also make red-bellied piranhas act bolder and more aggressive.
And this could theoretically result in feeding frenzies where each fish tries to get some of whatever finds its way into the water. Despite this kind of behavior being extremely rare, rumors of it launched the piranha’s international infamy. And this was in no small part thanks to former US President Theodore Roosevelt. In 1914, he published a bestselling book in which he called piranhas “the most ferocious fish in the world” and wrote that the scent of blood could incite them to rapidly devour an entire cow— or human— alive. But Roosevelt’s account is generally considered circumstantial and misleading. The “feeding frenzy” he witnessed is suspected to have been the result of people purposefully starving red-bellied piranhas, then giving them the opportunity to feed on a cow carcass— all to put on an exciting show. But where were we? Ah, yes. Falling into piranha-infested waters. So, what’s your fate? Let’s assume these are red-bellied piranhas. This being the Amazon River, they should be doing alright for themselves and not starving. Thankfully, you’re also not hitting the water alongside a bunch of fish guts. And ideally, you're not disrupting a piranha breeding extravaganza. You fall in, and the piranhas most likely avoid you. Calmly, softly swimming or wading to shore is generally recommended because splashing is thought to attract piranhas. Indeed, they’re equipped with the dentition to do damage, but they rarely attack humans. They usually have better things to eat. As you make your way onto dry land, there is no feeding frenzy where they skeletonize your body within minutes. And upon exiting the water, you're probably pleased to find no chunks of flesh missing.