40 Fun Facts About Piranhas

Which former US president's 1914 book cast piranhas as vicious killers after a trip to Brazil?

Theodore Roosevelt watched a school strip a cow to the bone within minutes. Local guides had staged the show, penning the fish in and starving them first.

Research on red-bellied piranhas found that they gather in shoals mainly for which purpose?

Self-defense is the point: a shoal shields each fish from cormorants and caimans. Scientists who expected cooperative hunters found shy fish hiding in a crowd.

CT scans confirmed that piranhas shed and regrow their interlocking teeth in which unusual pattern?

One side at once is how the teeth go, because they lock together like one long blade. Replacements grow underneath first, so a piranha is never left toothless.

Which blockbuster director's first feature was Piranha II: The Spawning, which he largely disowned?

James Cameron took over after the first director was fired, and the fish in his sequel can fly. He prefers to call The Terminator his first film.

Red-bellied piranhas, which mostly eat weak, dying or dead animals, are likened to which birds?

Vultures do the same clean-up job on land. Far from being relentless hunters, these piranhas are generally timid scavengers that pick off what is already doomed.

Which activity in the water attracts piranhas, so that children are bitten more often than adults?

Splashing draws piranhas in, as does the commotion of struggling fish near anglers. Some beaches in risky spots are fenced off with barriers.

The low-budget 1978 horror film Piranha cashed in on which blockbuster released three years earlier?

Jaws inspired a wave of cheap imitations, and its own director called Piranha the best of them. His praise helped head off a lawsuit from the studio.

Shoals of red-bellied piranhas have been known to feed on animals as large as which giant rodent?

Capybara can end up on the menu, as can wading birds such as egrets. Even so, piranhas mostly take animals that are already injured or dead.

Which plant-eating piranha cousin, with squarer teeth, is often mistaken for one in US waters?

Pacu are mostly vegetarian and can grow far bigger than any piranha, reaching up to 88 pounds. Many reported piranha catches turn out to be pacu.

Piranhas carry their razor-sharp teeth in which pronounced jaw alignment?

Underbite is the classic piranha look, with a strong lower jaw that sticks out. Their vegetarian relatives have squarer, straighter teeth and a much milder bite alignment.

Most piranha teeth have three cusps with a larger middle one, giving each tooth which overall shape?

Triangular, flat and blade-like, the teeth are built for puncturing and shearing. One rare species, the lobetoothed piranha, has five cusps on each tooth instead.

A red-bellied piranha's razor-sharp teeth are usually hidden from view by which facial feature?

Thick lips, fleshy enough to cover the teeth, give a resting piranha a surprisingly mild face. Beneath its high forehead sit the powerful muscles that drive the bite.

How are the sharp, tightly packed teeth of true piranhas arranged along the upper and the lower jaw?

A single row on each jaw is the piranha trademark, with small cusps locking neighboring teeth together. Their plant-eating relatives carry a double row up top.

A red-bellied piranha lifted from the water makes which sound with muscles around its swim bladder?

Drumming is the piranha's protest, a low-pitched sound made by fast-twitching muscles. In the water, the fish use different calls for face-offs, food fights and chases.

The wimple piranha has one of the narrowest diets known, with adults eating almost entirely what?

Scales are knocked loose when the wimple piranha rams another fish, then scraped off and swallowed. The attack leaves the flesh underneath undamaged.

A good share of a wild red-bellied piranha's diet is which body part, nipped from larger fish?

Fins nipped from the tails of bigger fish are a staple snack. Piranhas in aquariums nip each other too, and the damage grows back surprisingly fast.

Red-bellied piranhas dig shallow nests in flooded margins and attach their sticky eggs to what?

Water grasses hold the eggs, which hatch after just two or three days. The young then hide among the stems until they are big enough to look after themselves.

Before they are large enough to tackle small fish, what do newly hatched piranhas feed on?

Zooplankton, the tiny animals adrift in the water, are a hatchling's first meals. The eggs are laid in pits that the adults dig and then patrol.

A 1585 dictionary of Brazil's Old Tupi first recorded the word behind 'piranha' as which tool?

Scissors was the translation given, two years before a Portuguese explorer first applied the name to the fish. English had borrowed the word from Portuguese by 1710.

Which pink freshwater mammal, known in Brazil as the boto, eats piranhas among dozens of fish?

River dolphin diets are the most varied of any toothed whale, covering at least 53 kinds of fish. Adults turn pink as their skin is scuffed over the years.

Piranha bites on swimmers become more likely in which part of the year, when food is scarce?

The dry season lowers the water and packs piranhas into dense, stressed groups. Warning signs are sometimes posted at the riskiest swimming spots.

Although piranhas are sold as food at market, fishers often call them a nuisance for which habit?

Stealing bait is only the start: piranhas also eat hooked catches and damage fishing gear. They may bite the fisher too when hauled in by accident.

Besides carving wood, some peoples of Brazil and Bolivia use piranha teeth for which grooming task?

Cutting hair is one traditional job for the razor-edged teeth. They have also been used to sharpen hunting darts.

How does the adult black piranha, a hunter of deep river channels, normally live?

Alone is the rule for this red-eyed species, which is not a sociable fish. For its weight, it has one of the most forceful bites measured in any vertebrate.

In one review, which Venezuelan river basin ranked second to the Amazon for piranha species?

Orinoco waters held 16 of the review's 38 or so species, against 25 in the Amazon. Seven kinds of piranha share just one stream in the country.

Piranhas are characins, which makes them relatives of which small, popular aquarium fish?

Tetras and piranhas sit in the same order, Characiformes, which holds more than 2,000 species. Over 200 of them live in Africa.

Which peaceful, mostly plant-eating aquarium fish belong to the same subfamily as the piranhas?

Silver dollars sit in the piranha subfamily but are not called piranhas, thanks to their largely vegetarian diet. In a tank they will often eat every plant.

The piranha family's scientific name joins the Latin for 'saw' to the name of which fish?

Salmon gives Serrasalmidae its ending: the name means 'serrated salmon family'. The saw is the jagged keel running along the belly of these fish.

Chemists' 'piranha solution', which devours organic residue, mixes hydrogen peroxide with what?

Sulfuric acid and peroxide together strip organic residue from surfaces such as silicon wafers. The mix can dissolve fabric and skin just as easily.

In Nintendo's Mario games, the toothy Piranha Plant usually emerges from which green objects?

Warp Pipes have hidden Piranha Plants ever since Super Mario Bros. in 1985. The plant later became a playable fighter in Super Smash Bros. Ultimate.

In which 2022 DreamWorks film does Anthony Ramos voice the short-fused gang member Mr. Piranha?

The Bad Guys casts Mr. Piranha as the muscle of a criminal crew led by Mr. Wolf. The gang also includes a snake, a shark and a tarantula.

Doug and Dinsdale Piranha, London gangsters armed with sarcasm, feature in which troupe's sketch?

Monty Python based the Piranha brothers loosely on real London gangsters, the Kray twins and the Richardson gang. The sketch first aired on the BBC in 1970.

In which 007 film does the villain Blofeld drop a failed henchwoman into a pool of piranhas?

You Only Live Twice sends Helga Brandt into the piranha pool after she fails to kill Bond. The pool sits in Blofeld's base, hidden inside a volcano.

Piranha 3D sets prehistoric fish loose in the fictional Lake Victoria, located in which US state?

Arizona is the setting, and the film was shot on the state's real Lake Havasu. An estimated 80,000 gallons of fake blood went into the production.

Nearly 200 piranha attacks at one Brazilian lake in 2007 all involved bites to which body part?

Feet were the target every time, at an artificial lake created by damming the Tocantins River. Most piranha bites on people cause only minor injuries.

In one study of black piranha stomachs in Brazil, about a tenth of the contents was what?

Fruit and seeds turn up often enough that scientists class piranhas as omnivores. Their menu also runs to insects, crustaceans and leaves.

Which future star of That '70s Show had an early role in the 1995 television remake of Piranha?

Mila Kunis played Susie Grogan, a girl at a scout camp downstream of the killer fish. The remake was made for the Showtime network.

In the 1978 film Piranha, the mutant fish were bred by the military as a weapon for which conflict?

Vietnam War planners in the film wanted piranhas that could endure cold northern rivers. The secret project is called Operation Razorteeth.

The red-bellied piranha's scientific name honors Johann Natterer, a naturalist from which country?

Austria's imperial collection gained many specimens from Natterer, and numerous species bear his name. Modern research criticizes his reliance on exploiting slaves.

In Piranha 3D, which actor plays the pet-shop fish expert who identifies the prehistoric killers?

Christopher Lloyd plays Carl Goodman, a retired marine biologist who runs a pet fish store. He gives the monsters the scientific name of the real, far smaller red-bellied piranha.