Apart from sharks, piranhas are probably the most feared fish on the planet. Their reputation for being able to strip an entire cow to the bone in mere minutes dates back to 1913, when US President Teddy Roosevelt witnessed such an incident and described piranhas as “the embodiment of evil ferocity” (sounds like my ex). His character analysis seems slightly unfair, however, when you realise that this spectacle was actually staged in an effort to impress Roosevelt by local people, who had caught and starved the piranhas for weeks prior to his visit. But people are genuinely afraid of piranhas. Do we have a reason to be? Or has the reputation of this enigmatic little fish been wrongfully tarnished?
What Is A Piranha?
The term “piranha” is used to describe some 40 species of freshwater fish, found throughout South America. Contrary to popular belief, many species of piranha are actually herbivores, and feed exclusively on fruit, nuts and other plant matter. Only 2 species are considered potentially dangerous to humans, namely the black and red-bellied piranha. The black piranha is large and bulky, averaging up to 44cm (17-inches), and considered to have an aggressive temperament. Fortunately, black piranhas are also solitary, only coming together during mating season. Most attacks are attributed to the aptly-named red-bellied piranha. Though no less aggressive, this species is slightly smaller than its black cousin, growing up to 35cm (14-inches) in length – though individuals up to 50cm (19.5-inches) have been recorded. Unlike the black piranha, red-bellied piranhas live together in shoals. Many believe they do this because it enables them to take on larger prey, but experts believe it is more likely to be for protection. Despite their fearsome reputation, both black and red-bellied piranha are primarily scavengers, feeding off of fruit and other plant matter, as well as animal carcasses and flesh nipped from the fins of larger fish.
Under normal circumstances, both species actively avoid humans in the water (live ones, anyway). So where does their bloody reputation come from?
Piranha Attacks On Humans
Officially, the number of humans killed by piranha every year is….zero. The number of humans ever killed by piranha is…wait for it…zero. Yes, really. There are no confirmed fatal attacks by piranha on humans. Note: “confirmed”. When it comes to actual statistics surrounding piranha attacks, the waters are decidedly muddy (lol). The issue appears to be that much of the evidence is merely “anecdotal” (scientific translation: doesn’t count). However, to the people who live alongside piranha, the threat is perhaps minimal, but real, as demonstrated by the behaviours they adopt at certain times of the year. For example, during mating season (piranha’s, not ours), people tend to avoid the water. Why? Because piranhas are known to become defensive over their nests and young. Similarly, during dry months, when food is scarcer and mouths hungrier, people tend not to enter the water. There is a reason for this change in human behavior, namely, they do not want to get eaten, slightly or otherwise.
What Do We “Know” About Piranha Attacks?
Every year, there are roughly 200 reported piranha attacks on humans, none of which are fatal. The majority of these attacks occur during the dry season, when people are cooling off in the water (piranha territory). For example, on Christmas Day, 2013, some 70 people were attacked in the Paraná River, in Rosario, Argentina. The victims all suffered bites mainly to the hands and feet, with the worst injuries resulting in the partial loss of fingers and toes. A spate of attacks in Brazil in 2016 saw 50 incidents over the course one month, resulting in similar injuries. The summer of 2007 was one of the hottest on record for Suriname, and saw around 70 people sustain minor injuries due to piranha attacks. While undeniably unpleasant, these injuries are all relatively minor. So what about more serious attacks? Well, there have been numerous reports in the media over the years with headlines such as: “Piranhas eat girl, 6, after canoe capsizes in Brazil” (The Telegraph), or “Piranha attacks in Paraguay leave 4 dead, more than 20 injured this year” (New York Post), which imply that piranhas actually killed humans. However, in almost all of these cases, autopsy or witness reports suggest or even confirm that the victims were already dead, or at the very least, unconscious, before the piranhas attacked. Indeed, under normal circumstances piranha are very wary of humans and will go out of their way to avoid them. However, it is known that, under certain circumstances, piranhas will attack much larger prey, such as birds or capybara, if they are drowning or otherwise weakened. Would they do the same to a human (particularly a small one) if they were hungry enough? According to some, yes. In an episode of Animal Planet’s “River Monsters”, biologist Jeremy Wade interviewed the inhabitants of a remote Brazilian village, which sits on the Amazon river. One man described how his grandchild, a toddler, fell into the water and was dead before he was pulled out. The piranhas had apparently killed him in seconds. During dry season, the people who live along the river do not even enter the water to wash, because of the danger the piranha pose.
How Dangerous Are Piranhas?
Are piranhas bloodthirsty monsters that will shred you to the bone in minutes? No. Are they shy, docile little goldfish you can happily swim with? Not always. Under certain circumstances, when the temperatures are high and the water is low, when there is nothing available to eat and they are on the point of starvation, piranhas are demonstrably capable of attacking a live human. Mostly, people are able to get out of the water before too much damage is done. But what if they couldn’t? What if the people who live on the water did not avoid it during dry months? What if more effort was made by the scientific community to investigate the considerable anecdotal evidence of piranha attacks? In this author’s (obviously expert-and-always-right) opinion, the number of confirmed fatal piranha attacks on humans would be somewhat higher than zero…