Piranha feeding frenzies are a famed occurrence. They usually occur with the red bellied species – black piranhas don’t seem to work themselves up into the same state of violence. Piranhas can scent blood from several hundred feet away through the water, as sharks can. Sometimes the smell of blood n the water will send red belly piranhas into a feeding frenzy. This sensitivity comes from the fact that piranhas’ bodies are covered with taste buds, which help them determine whether a passing fish is worth eating or not5.
Mechanism of a piranha attack
A piranha feeding frenzy actually has some organization to it, although this can be hard to determine among all the churning blood and boiling water! If they are hunting in a group, when a single fish encounters a piece of prey, it signals the others acoustically – piranhas have excellent hearing. Each member of the piranha group rushes in to take a bite, and will then move back to make way for others[2]. They have an excellent sharing and turn-taking system.
Frequency of piranha attacks
There are no confirmed reports of a live person being killed and eaten by a school of piranhas in a feeding frenzy. Most bites by piranha fish occur when somebody puts their hand into the aquarium filled with underfed fish, or when they make the fish feel threatened.
Piranha attacks are relatively rare, even on live animals. Most piranhas scavenge more than they hunt. To prove this fact, Dr Axelrod, a fish expert, once waded into a tank filled with piranhas on network television, wearing only swim trunks. He then dangled a piece of meat on a line into the water – the piranhas attacked the meat, but didn’t attack Dr Axelrod[6].
A study in Brazil showed that most piranha bites are related to an adult piranha defending its brood of young, and consist only of a single bite[7]. Dr Jan Mol, of the University of Suriname, has said “In 15 years of field work in Suriname, often wading for hours through ‘piranha-infested’ streams and catching piranhas with hook and line while bathing in the river, I was never injured by free-swimming piranhas”.
“Piranhas are usually more dangerous out of the water than in it and most bites occur on shore or in boats when removing a piranha from a gillnet or hook, or when a ‘loose’ piranha is flopping about and snapping its jaws”, Dr Mol continued.
In Italy, in a dangerous animal circus known as Il Circo Degli Orrori (The Circus of Horrors), slave girls were made to swim with black piranhas in a tank filled with near freezing water. Police shut the circus down – however the girls were never attacked.
Any notable cases
The most famous piranha feeding frenzy, and perhaps the one which created the entire stereotype, was a spectacle set up by Brazilian fishermen to impress US President Teddy Roosevelt on his visit to Brazil. A portion of the Amazon tributary was blocked off with nets, and a large number of piranhas were put into the ‘cage’. They were grossly underfed in the lead -up to President Roosevelt’s arrival, when the fishermen sliced up a cow’s carcass and tossed it into the river. Naturally, the resulting piranha feeding frenzy quickly reduced the carcass to bones, and the impact it made on Teddy Roosevelt could clearly be felt through reading his book, Through the Brazilian Wilderness
.
Another famous case of a piranha feeding frenzy reportedly occurred on September 20th, 1981. A boat named the Sobral Santos was sailing through the Obidos, a part of the Amazon River that is infested with piranhas. The boat collapsed, and in the process, injured some of the passengers aboard. There were 300 people aboard[4], and all were killed. Some sources[3] state that it was a piranha feeding frenzy that killed all of the people, however others state that there have been no reported attacks on live humans. In reality, it is likely that passengers were eaten by piranhas, but certinaly not confirmed.
In Brazil since the damming of certain parts of the Amazon River, piranha attacks on people bathing have been increasing[5]. However none of these has been known to be fatal.
Piranha Attacks
Piranha feeding frenzies are a famed occurrence. They usually occur with the red bellied species – black piranhas don’t seem to work themselves up into the same state of violence. Piranhas can scent blood from several hundred feet away through the water, as sharks can. Sometimes the smell of blood n the water will send red belly piranhas into a feeding frenzy. This sensitivity comes from the fact that piranhas’ bodies are covered with taste buds, which help them determine whether a passing fish is worth eating or not5.
Mechanism of a piranha attack
A piranha feeding frenzy actually has some organization to it, although this can be hard to determine among all the churning blood and boiling water! If they are hunting in a group, when a single fish encounters a piece of prey, it signals the others acoustically – piranhas have excellent hearing. Each member of the piranha group rushes in to take a bite, and will then move back to make way for others[2]. They have an excellent sharing and turn-taking system.
Frequency of piranha attacks
There are no confirmed reports of a live person being killed and eaten by a school of piranhas in a feeding frenzy. Most bites by piranha fish occur when somebody puts their hand into the aquarium filled with underfed fish, or when they make the fish feel threatened.
Piranha attacks are relatively rare, even on live animals. Most piranhas scavenge more than they hunt. To prove this fact, Dr Axelrod, a fish expert, once waded into a tank filled with piranhas on network television, wearing only swim trunks. He then dangled a piece of meat on a line into the water – the piranhas attacked the meat, but didn’t attack Dr Axelrod[6].
A study in Brazil showed that most piranha bites are related to an adult piranha defending its brood of young, and consist only of a single bite[7]. Dr Jan Mol, of the University of Suriname, has said “In 15 years of field work in Suriname, often wading for hours through ‘piranha-infested’ streams and catching piranhas with hook and line while bathing in the river, I was never injured by free-swimming piranhas”.
“Piranhas are usually more dangerous out of the water than in it and most bites occur on shore or in boats when removing a piranha from a gillnet or hook, or when a ‘loose’ piranha is flopping about and snapping its jaws”, Dr Mol continued.
In Italy, in a dangerous animal circus known as Il Circo Degli Orrori (The Circus of Horrors), slave girls were made to swim with black piranhas in a tank filled with near freezing water. Police shut the circus down – however the girls were never attacked.
Any notable cases
The most famous piranha feeding frenzy, and perhaps the one which created the entire stereotype, was a spectacle set up by Brazilian fishermen to impress US President Teddy Roosevelt on his visit to Brazil. A portion of the Amazon tributary was blocked off with nets, and a large number of piranhas were put into the ‘cage’. They were grossly underfed in the lead -up to President Roosevelt’s arrival, when the fishermen sliced up a cow’s carcass and tossed it into the river. Naturally, the resulting piranha feeding frenzy quickly reduced the carcass to bones, and the impact it made on Teddy Roosevelt could clearly be felt through reading his book, Through the Brazilian Wilderness
.
Another famous case of a piranha feeding frenzy reportedly occurred on September 20th, 1981. A boat named the Sobral Santos was sailing through the Obidos, a part of the Amazon River that is infested with piranhas. The boat collapsed, and in the process, injured some of the passengers aboard. There were 300 people aboard[4], and all were killed. Some sources[3] state that it was a piranha feeding frenzy that killed all of the people, however others state that there have been no reported attacks on live humans. In reality, it is likely that passengers were eaten by piranhas, but certinaly not confirmed.
In Brazil since the damming of certain parts of the Amazon River, piranha attacks on people bathing have been increasing[5]. However none of these has been known to be fatal.