The Common Piranha Myth You Should Stop Believing

There's a common belief that piranhas can devour a human body in minutes and leave the bones picked clean of flesh. This scene has been depicted in countless movies and shows, which is why most people believe it to be true. As kids, parents warn their children of the dangers of being in piranha-infested waters, but what really is the truth?

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It's a fact that piranhas have extremely sharp teeth that can tear away at flesh, but surprisingly, they're not as vicious as they are believed to be. According to Mother Jones, piranhas are not naturally aggressive creatures. They scavenge for food and typically feast on smaller fish, insects, and plants. There are cases where they eat carcasses of dead animals, but they do so as the food source is already readily available. In instances where they are around predators, piranhas go into their defensive mode and stay together to defend themselves rather than attack.

Where did the myth originate?

The story of piranhas devouring humans can traced back to 1913 when Theodore Roosevelt traveled to South America to visit the Amazon. He wrote about his time there in the book "Through the Brazilian Wilderness" and had a descriptive paragraph on the behavior or piranhas. "The piranhas habitually attack things much larger than themselves. 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," he wrote (via Smithsonian Magazine). Roosevelt went on to describe piranhas as capable of devouring humans and large beasts and that blood in the water "excites them to madness."

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The truth is, when Roosevelt went to the Amazon, locals wanted to put on an impressive show for the political figure. Piranhas were placed in an area enclosed with nets on a portion of the Amazon, and they were left there unfed before Roosevelt's arrival. Per an article on Mental Floss, a cow was tossed into the water when Roosevelt came, and it was then when the feeding frenzy began. The water turned bloody red and after a few minutes, the cow's bones were the only ones left. What Roosevelt witnessed was a show and far from piranhas' natural behavior. Many read Roosevelt's account, and the myth about piranhas was born.

Experiments prove piranhas are not vicious

Dr. Herbert Axelrod was a tropical fish expert who wanted to disprove Theodore Roosevelt's claims of piranhas being beasts. And so, he conducted a few experiments involving piranhas and used himself as bait. A pool was filled with piranhas, specifically the red-bellied piranhas that were native in the Amazon, and Axelrod entered the pool with nothing but his swimming trunks. The piranhas left him alone and he exited the pool without a single bite, per Lethbridge News Now. He tried the same experiment again, the second time bringing with him some bloody meat. Although the piranhas fed on the meat, they left the doctor unharmed, proving that Roosevelt was wrong about the fish.

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There have been reported incidents of piranhas feeding on humans, but in those instances, most coroners reported that the feeding happened post-mortem and not because piranhas were responsible for the death.

Despite all the findings, experts still caution people of piranhas as they may bite when they feel threatened such as during their mating season and when they are hungry.

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