Josephoartigasia Monesi is the biggest rodent ever to have lived. It was discovered in Uruguay, South America. It may have weighed a ton! It is much bigger than the most similar living rodent, the Pacarana which only weighs about 15 kilograms (33 lb).
It lived in lowland rain forests and it may have eaten soft plants because its molars were small and not good for chewing on hard food. But it had a huge front teeth which were more than 30 centimetres long. These huge teeth protected them from saber-toothed cats. They would fend off their predators by showing off their huge front teeth. Their total body length was about 3 metres with a height of 1.5 metres.