pack rat, rodent rodent, member of the mammalian order Rodentia, characterized by front teeth adapted for gnawing and cheek teeth adapted for chewing. The Rodentia is by far the largest mammalian order; nearly half of all mammal species are rodents.
..... Click the link for more information. of the genus Neotoma, of North and Central America, noted for its habit of collecting bright, shiny objects and leaving other objects, such as nuts or pebbles, in their place; also called trade rat or wood rat. Most common in the southern and western parts of the United States, but found as far south as Nicaragua, the pack rat stores the objects it collects to decorate its nest. The rodent may reach a length of 18 in. (45.7 cm) including tail, has soft brown fur, and resembles a squirrel with large ears. It eats nuts, berries, seeds, twigs, and roots. Its nest is a large stick structure built in a sheltered area. The desert species adorns its nest with bits of cactus, turning it into an impenetrable fortress. A litter is born after a gestation period of 33 to 39 days and contains from two to six young. Pack rats are classified in the phylum Chordata Chordata (kôrdā`tə,–dä`–)
..... Click the link for more information. , subphylum Vertebrata, class Mammalia, order Rodentia, family Cricetidae.

wood rat

or pack rat

Any of 22 species (genus Neotoma, family Cricetidae) of rodents that are nocturnal vegetarians of North and Central American deserts, forests, and mountains. Wood rats are buff, gray, or reddish brown, usually with white undersides and feet. They have large ears and are 9–19 in. (23–47 cm) long, including the 3–9-in. (8–24-cm) furry tail. The nest, up to 3 ft (1 m) across and usually built of twigs or cactus, is placed in a protected spot (e.g., under a rock ledge). Wood rats are sometimes called pack rats because they collect material to deposit in their dens.