The young remain in their mother's burrow for about two months and then disperse. They reach adult weight at about five to six months and are sexually mature by the following breeding season. Most pocket gophers do not live past their second year. They are preyed upon at night by owls and are dug out of their burrows by badgers, coyotes, and foxes. The oldest wild individuals found in a tagging study were four years old.
Pocket gophers are generally valuable to human interests.
Their tunneling helps keep the earth porous and friable, and they enrich the soil by burying vegetation, which forms humus. In mountain meadows water and soil are conserved when the runoff from melting snow sinks deep into the gopher burrows. These animals are sometimes accused of damaging grasslands, but actually overgrazing by domestic livestock does the damage, and then excessive gopher populations are attracted by the vegetative conditions created. In agricultural areas, however, these animals may eat crops, cut the roots of young trees, and cause local flooding by tunneling through dikes. Hundreds of subspecies of Thomomys have been described, many of them from a single restricted locality.