Oecomys concolor (Natterer's Oecomys) is a species of rodents in the family cricetids . They are found in The Neotropics. Individuals can grow to 280 mm.
Definition: The largest scale biogeographic division of the earth's surface based on the historic and evolutionary distribution patterns of plants and animals.
Definition: A group of species that exploit the same food resources, and/or use the same feeding or foraging methods. http://en.wikipedia.org/wiki/Guild_(ecology)