A member of a non-computer related family of rodents, the pocket gophers, belonging to Geomyidae (Greek for "earth mice"). They are native to North and Central America. Alternatively, ground squirrels such as marmots and groundhogs, which resemble the species in Geomyidae.

Members of Geomyidae have yellow incisors, which are always exposed, even when their mouths are shut. Their eyes and ears are small, and they have short, hairless tails. Their front claws are curved like a mole's, an obvious adaptation for digging. Indeed, they are the bane of lawn care. The mounds they create are characteristically fan-shaped. The entrances to their tunnels are denoted by plugs of earth. They do not like being above ground, though they do occasionally forage.

Pocket gophers are so named because they have fur lined external cheeks that can be turned inside out. In effect, pockets on their heads. They use these strange fashion accessories to carry food around. They love to hoard food, and can form huge caches of vegetable matter. Being subterranean, they mostly eat roots, tubers, and anything else a plant is careless enough to place below ground.

They are mostly solitary, and care nothing for night or day, being active at all hours. Size ranges from 120 to 229 centimeters (4 and three quarters to 9 inches). Most are brown, to match the soil. They are polygamous, and some are territorial. There are many subspecies.

Species:
Cratogeomys bursarius
Cratogeomys castanops (yellow-faced pocket gopher)
Cratogeomys fumosus (smoky pocket gopher)
Cratogeomys goldmani
Cratogeomys gymnurus (Llano pocket gopher)
Cratogeomys merriami (Merriam's pocket gopher)
Cratogeomys neglectus (Queretaro pocket gopher)
Cratogeomys tylorhinus (naked-nosed pocket gopher)
Cratogeomys zinseri (Zinser's pocket gopher)

Geomys arenarius (desert pocket gopher)
Geomys attwateri
Geomys breviceps
Geomys bursarius (Plains pocket gopher)
Geomys knoxjonesi
Geomys lutescens
Geomys personatus (South Texas pocket gopher)
Geomys pinetis (southeastern pocket gopher)
Geomys streckeri
Geomys texensis
Geomys tropicalis (tropical pocket gopher)

Orthogeomys cavator (Chiriqui pocket gopher)
Orthogeomys cherriei (Cherrie's pocket gopher)
Orthogeomys grandis (giant pocket gopher)
Orthogeomys heterodus (variable pocket gopher)
Orthogeomys hispidus (hispid pocket gopher)
Orthogeomys underwoodi (Underwood's pocket gopher)

Pappogeomys alcorni (Alcorn's pocket gopher)
Pappogeomys bulleri (Buller's pocket gopher)

Thomomys bottae (Botta's pocket gopher)
Thomomys bulbivorus (Camas pocket gopher)
Thomomys mazama
Thomomys monticola (mountain pocket gopher)
Thomomys talpoides (northern pocket gopher)
Thomomys talpoides yakimensis
Thomomys townsendii (western pocket gopher)
Thomomys umbrinus (southern pocket gopher)

Zygogeomys trichopus (tuza)

Sources: Peterson Field Guides: Mammals by Burt and Grossenheider
http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=10010