Do Piranhas Really Eat Humans?

Piranhas are known for being ferocious man-eaters, but do they really attack humans? Find out what’s behind the myth and how piranhas got their bad reputation.

Jun 11, 2023By Nancy Schaffer
_AI do piranhas eat humans

Hollywood has done a good job convincing people that piranhas are deadly fish that will devour unsuspecting victims. While these omnivorous fish do take a bite out of people every now and then, it’s nothing like what is represented in the movies. Keep reading to find out more about piranha attacks, what they eat, and how they got a reputation as one of the most dangerous fishes in the world.

Do Piranhas Attack Humans?

piranha tooth

Piranhas have been known to bite humans on rare occasions, but there are only a few documented attacks. They are a common freshwater fish native to the rivers of South America. It is unknown how many species of piranha exist in the Amazon, but estimates range from around 30 to 60.

Piranhas are known for their razor-sharp teeth. In fact, their name is derived from words that literally translate to “fish tooth” in the language of the Tupi tribe. While people fear piranhas because of their reputation, attacks on humans are extremely rare and can usually be avoided.

In most cases, piranha attacks are defensive actions taken when they feel threatened, such as when being handled by fishermen. It is rare for them to attack people, and when they do, the attacks usually result in minor injuries.

What Do Piranhas Eat?

red bellied piranha

Most piranhas have a varied diet of seeds, frogs, mollusks, other fish, insects, plants, and fruit. Some species are predatory fish that are purely carnivorous, but on the other hand, there are species that only eat plants.

Piranhas will attack live animals when they are weakened, but it is much more common for them to devour animals that are already dead.

How Did Piranhas Get Their Reputation?

predatory fish

The bad reputation of piranhas as ferocious man-eating carnivores has been perpetuated by sensationalized movies, like the 1978 movie Piranha and the 2010 remake by the same name, but it didn’t start there. In America, it was Teddy Roosevelt who first introduced the public to piranhas in 1914.

The red-bellied piranha lives in large groups called shoals that consist of 20 to 30 individuals. Roosevelt’s extraordinary account of how a shoal of piranhas stripped the meat off a dead cow within a matter of minutes is full of titillating language. Teddy used exciting words like “ferocious,” “fury,” “rabid,” “vicious,” and “fearsome” to describe the piranha, making it seem more dangerous than it is.

Even though piranhas have a bad reputation, most aren’t as dangerous as the myth makes them seem. On the contrary, the red-bellied piranha, the species most commonly found in home aquariums, is shy and mild-mannered.

Why Do Piranhas Attack?

piranhas shoal

The truth about piranhas is that they usually prefer to eat smaller prey like fish and aquatic insects, and they aren’t the bloodthirsty monsters they’ve been made out to be. Piranhas are scavengers, and they are essentially one of nature’s most opportunistic omnivores.

The most common reason for piranhas to attack is when the male is protecting its young. Like most fish, the female of the species lays her eggs, which are then externally fertilized by the males. The male piranhas stick around to help protect the young, a behavior they share with male catfish.

Both genders of piranha will aggressively protect the area where the eggs are incubating until they are hatched, which takes four to six weeks. If a person or animal accidentally stumbles upon them, they can fall prey to a piranha attack.

Piranha Attacks on Record

piranha fish shoal

Piranha attacks are sensationalized by the media, just like the danger of shark attacks is wildly exaggerated. There are several documented piranha attacks on humans, but the dangers associated with piranhas are low as long as you avoid swimming with them during the dry season. Like many predators, including sharks, bears, and wolves, they usually leave you alone.

One of the most shocking attacks on record is the incident in 2013 when over 70 people were attacked in the Parana River. The group of people, which included 20 children, were trying to escape the heat. Even though they described the attack as “very aggressive,” they were back in the water within 30 minutes of the attack. Only a few minor wounds were sustained.

A more tragic story involved a six-year-old girl. In 2015, Ardila Muniz was with her siblings and grandmother when a storm capsized their small canoe. The grandmother got all the other children to safety, but the river swept Ardila away. She died after being pulled from the river, and there were large piranha bites on her thighs. Reports showed she was weakened, and it is unclear if she died from drowning or blood loss. In any case, it was likely a case of opportunistic feeding rather than a frenzied attack.


Thanks to Teddy Roosevelt and Hollywood, piranhas have a bad reputation, but the truth is that they are not the man-eating monsters that are portrayed in films. Piranhas rarely attack humans, and even when they do, it’s usually not severe. They are mostly scavengers that feed on plants, insects, and other fish.

So, while they may give you a little nip here and there, it’s nothing to fear.

Nancy Schaffer
By Nancy Schaffer

Nancy is a dog lover with a special place in her heart for Labradors. She has been surrounded by dogs her whole life and now has two of her own - a chocolate named Betty Belle and a black Lab named Darcy Bear. Nancy’s love for dogs began at a young age, and she has always been drawn to this breed’s friendly and affectionate nature. When she's not snuggling with her pups, Nancy can be found hiking or camping with her dogs. They are always ready to go outside!