Animal · Brazil, Peru, Colombia
Red-bellied piranha
Pygocentrus nattereri — the name this animal has in the language scientists everywhere share.
The red-bellied piranha is a silver river fish from South America with an orange belly and a jaw full of triangular teeth. Films make piranhas look like monsters, but most days they nibble insects, fruit, seeds and fish that are already dead. They swim in groups mainly to stay safe from bigger hunters.
Picture credit: Joshyja (CC BY-SA 3.0) · FF23-fr (CC BY-SA 3.0) · Wikimedia Commons
Where does the red-bellied piranha live?
Home: Warm rivers, creeks and flooded forests of tropical South America.
In the wild it lives in these countries: Brazil, Peru, Colombia, Venezuela, Bolivia, Guyana, Paraguay, Ecuador.
Conservation status from the IUCN: not in danger.
The short profile
Fully grown: usually up to 35 cm long. It weighs about 1 kilograms. On the menu: both plants and meat.
The story behind it
A red-bellied piranha has one row of sharp, triangular teeth in each jaw, and they meet like the blades of a pair of scissors when its mouth shuts. That bite is built for taking a piece out of something, not for swallowing large prey whole. On most days a piranha eats insects, worms, small fish, and the fruit and seeds that drop into the water from the flooded forest above. It also clears away animals that have already died, which helps keep the river clean. Piranhas gather in shoals, but not to hunt as a team: a group means more eyes watching for the caimans, river dolphins and big birds that eat them. They can make grunting and drumming sounds by shaking a muscle against the swim bladder, usually when they are annoyed with each other. Parents clear a patch of riverbed, lay their eggs there and drive away anything that comes near. The famous tale of cattle stripped to the bone came from fish that had been kept hungry on purpose to impress a visiting president.
Find it on the globe
Red-bellied piranha is there as a tiny animated figure that breathes and looks around. From far away the planet is only a blue ball; detail arrives as you zoom in, and this one appears once you are close enough. Open it on the globe.
It sits at its real coordinates, not near them — the same numbers listed in the facts above. Switch off the layer for this kind of place and it disappears again; the buttons for that are down the right-hand edge.
Questions children ask
Would a piranha really eat a person?
No. There are bites on feet and hands, usually where fish are crowded into a shrinking pool in the dry season. People swim and wash in piranha rivers every day without trouble.
Why is the belly orange?
The bright underside is a signal to other piranhas and is strongest in grown-up fish. Seen from the side, the rest of the body still blends into the murky brown water.
Do piranhas hunt in packs?
They swim together, but each fish grabs its own food. The shoal is mostly protection, because plenty of bigger animals in the river would happily eat a piranha.
Where these numbers come from
Every figure on this page was checked against public reference sources before publication. Where sources genuinely disagree, the text says so.
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