What is the worlds largest rodent

Capybara

The capybara (Hydrochoerus hydrochaeris ), also known as capibara, chigüire in Venezuela, Colombia, and Ecuador ronsoco in Peru, chigüiro, and carpincho in Spanish, and capivara in Portuguese, is the largest living rodent in the world.Its closest relatives are agoutis, chinchillas, coyphillas, and guinea pigs.

Here is a picture : http://en.wikipedia.org/wiki/File:Capyba…

The Capybara Is the worlds largest living rodent.
The largest rodent that is know to have lived is Josephoartigasia monesi. It lived around 2 million years ago.

Everyone else beat me to Capybarra, so I am going to say the second largest is the Agouti.

Capybara. It's a South American relative of Guinea Pigs.

http://en.wikipedia.org/wiki/Capybara

Capaybaras...

Capybara