Welcome to Brainstuff, a production of iHeartRadio, Hey Brainstuff. Lorn voleban here. When Theodore Roosevelt went on a hunting expedition in Brazil in nineteen thirteen, he got his money's worth. Standing on the bank of the Amazon River, he watched piranhas attack a cow with shocking ferocity. It was a scene out of a horror film of water boiling with frenzied piranhas and blood, and after about a minute or two,
a skeleton floating to the suddenly calm surface. Roosevelt was appropriately shocked and talked about it in his nineteen fourteen book Through the Brazilian Wilderness. He wrote, they are the most ferocious fish in the world. They will snap a finger off a hand incautiously trailed in the water. They mutilate swimmers. In every river town in Paraguay there are men who have been thus mutilated. They will rend and devour alive any wounded man or beast, for blood in
the water excites them to madness. Thus the American legend of the piranha had begun. Hollywood picked it up from there with the nineteen seventy eight horror flick Piranha, directed by cult film Officionado Jo Dante, notably right after the smash hit Jaws came out in nineteen seventy five, When flesh eating piranhas are accidentally released into a summer resorts rivers,
the guests become their next meal. It was followed by nineteen eighty one's Piranha two The Spawning, which was James Cameron's directorial debut, and then a comedic remake of the original in twenty ten Pirana three D, followed by its sequel in twenty twelve, Pirana three Double D. All of this, although purposefully silly, cemented the idea of the piranha as a threat in our minds. But is this fish's vicious reputation desert let's find out. First off, we're not talking
about gargantuan monsters here. Piranhas top out at about two feet long that's sixty centimeters, and most are only about eight inches or twenty centimeters and weigh just a few pounds. The most aggressive of the roughly twenty species found in the Amazon River, the red bellied piranha, is on the small end of the spectrum and usually weighs about three pounds or a little less than one and a half kilos. However, in the case of piranhas, it's not the size that counts.
It's the bite. A piranha's teeth they're only about a quarter inch long around four millimeters, but they're very finely serrated, and the whole jaw mechanism is designed for chomping efficiency. The teeth are spaced in an interlocking pattern, so when a piranha jaw snaps shut, the top teeth and bottom teeth interlace like dozens of pairs of scissors, and their jaws are strong they can bite right through the bone
of say a human tow. Furthermore, piranhas don't chew. When they bite down, the chunk of flesh they take out of their prey goes right into their bellies. They just keep snapping their jaws shut and filling themselves up. Also, paranas are very efficient team eaters. A school and a feeding frenzy will rotate continuously, so as each piranha takes a bite, it moves out of the way so that the fish behind it can get a bite, and so on. They take turns at such speed that you get that
boiling water effect. If a large enough school was aggressive enough It's entirely possible for piranha's too strip an animal as big as a cow in just a few minutes, if not under sixty seconds. But the key thing to know about Roosevelt and his story is that although he explored the Brazilian Amazon as an avid hunter, he wasn't exactly the average tourist. He was a former US president traveling with dozens of journalists, and his guides wanted him
to be very pleased with his trip. Feeding frenzies are not an everyday occurrence. Roosevelt's guides in Brazil had set up the scene for their famous guest. They set nets to close off a small part of the river and tossed hundreds of piranhas into it, trapping them at a larger density than their usual school of twenty plus. By the time they threw that poor cow into the water, the poor piranhas were stressed and starving, So eating an entire cow in a minute or two is not the norm.
But what and how do piranhas usually eat. Attacking a live, land based animal isn't out of the question for piranhas. They have been known to attack sick or old animals that come to drink from the river. When a cow lowers its head, they'll clamp off to its face. If the cow is too weak to fight back, the piranhas will drag it into the water and beat it. But live mammals are not the mainstay of their diet. Mostly
in that category they're scavengers. The skeletons of people and other land based animals found in the Amazon apparently eaten by piranhas weren't attacked alive. They were already dead when the piranhas got to them. As with other fish, land based mammals are by no means a big part of the purana's diet. They eat other fish, mostly including sometimes other puranas, along with insects, worms, and shrimp. They will ambush prey by lurking and then dashing out, but puranas
aren't even strictly carnivores. They'll eat pretty much anything they can get, including fruits and other plants, especially when they're young. The truth is that, contrary to legend, most piranhas don't really attack anything. Most of the species and the Amazon survive in entirely by taking small bites out of the fins and scales of other fish as they pass by. The fish swim away only slightly disturbed, and their fins
and scales grow back. Humans can also get in necked deep enough to need stitches, and sadly, that is happening more often in recent years, as dams and human habitation having encroached on piranha's native territory in the fresh water ponds and creeks of South America. To come full circle of life, piranhas themselves have few predators, aside from humans who sometimes catch them as food or kill them as
a pest. Even though puranhas are small, they're seldom eaten by larger fish that tend to gulp their prey that razor sharp bite would really hurt going down. But during the dry season, piranhas are eaten regularly by herons and cayman lizards. When water levels are low and the fish end up trapped in increasingly small ponds but no food, Unable to defend themselves, the herons and cayman's come in
and finish them off. Because of that lack of predators, many countries of outlawed the import or possession of piranhas, even as aquarium pets, the risk they might be released into local waters and cause a serious threat to the ecological balance there is too great. But still as hazardous as piranhas can be in large and hungry numbers, you probably don't need to be as worried about them as
Theodore Roosevelt or the B movies tell you. Today's episode is based on the article can piranhas really strip a cow to the bone in under a minute? On how stuffworks dot com, written by Julia Layton. Brain Stuff is production by Heart Radio in partnership with how stuffworks dot Com and is produced by Tyler Klang. Four more podcasts my heart Radio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.