Animal · Argentina, Uruguay, Paraguay
Coypu
Myocastor coypus — the name this animal has in the language scientists everywhere share.
The coypu is a large water rodent from South America with bright orange front teeth and a long round tail like a rat's. Fur farms carried it to Europe, Asia and North America, where it now lives wild.
Picture credit: Norbert Nagel (CC BY-SA 3.0) · Norbert Nagel (CC BY-SA 3.0) · Petar Milošević (CC BY-SA 4.0) · Wikimedia Commons
Where does the coypu live?
Home: Reedy river banks, marshes and canals with slow water.
In the wild it lives in these countries: Argentina, Uruguay, Paraguay, Brazil, Bolivia, Chile.
Conservation status from the IUCN: not in danger.
The short profile
Fully grown: 40-60 cm head and body, plus a round tail of 30-45 cm. It weighs about 7 kilograms. On the menu: plants.
The story behind it
The orange colour of a coypu's front teeth comes from iron in the enamel, which makes them extra hard. It needs them: the animal cuts through reeds, rushes and water plants all day and can strip a marsh bare. A female's teats sit high on her flanks instead of on her belly, so the young can drink while she swims. Coypus dig long burrows into river banks, and in places where they were released or escaped from fur farms those tunnels weaken dikes and flood defences. That is why the coypu, harmless at home in South America, counts as an unwanted invader in Europe and North America.
Find it on the globe
Coypu 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
Why are a coypu's teeth orange?
Iron is built into the enamel of the front teeth, and it stains them orange. The same iron makes the enamel harder, which helps when you cut through tough reeds every day.
Is the coypu the same as a beaver?
No. Both are water rodents, but a beaver is much heavier and has a broad flat tail, while the coypu's tail is thin and round like a rat's. Coypus also build no dams.
Why is the coypu a problem in Europe?
It does not belong there. Animals escaped from fur farms, and their burrows weaken river banks and dikes while their appetite clears whole reed beds that birds need for nesting.
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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