The Fero Rat is the only "native" mammal on Belizo. That is, the only mammal found by settlers.
The Fero Rat was transplanted to Belizo by the Ancients about 350,000 years ago.
The Fero is brownish in color which actually makes it stand out against the sometimes blueish plants of Belizo, but since it has no preditors this doesn't cause any problems. The adult Fero is usually between two and three inches long (not counting the tail).
The Fero Rat is an omnivore. It hunts and eats any of the insects found on Belizo (the Meso Beetle, the Green Scorpion, and the Desert Ant). But it also eats Blueberries, Prickleberries, and some of the mosses and lichens, as well as the occasional Belizo Mushroom.
The Fero Rat is the top of the Belizo food chain. There are no animals which hunt it, and like most hunters its numbers are regulated by the available food supply. In addition to these natural cycles the Fero Rat clearly also self regulates its numbers to some degree, and so usually avoids deep crashes if the food supply is small.