The naked mole rat is the first mammal discovered to exhibit eusociality. It is native to the drier parts of the tropical grasslands of East Africa. It is also of interest because it is extraordinarily long-lived for a rodent of its size (up to 31 years) and holds the record for the longest living rodent. Naked mole rats are highly resistant to cancer and maintain healthy vascular function longer in their lifespan than shorter-living rats.