Thomomys bottae
Botta's pocket gopher

Thomomys bottae ranges from southern Oregon and central Colorado to southern Baja California and central Mexico (Nowak 1991).

Valley pocket gophers are primarily fossorial. They burrow in various habitats including high mountain valleys, deserts, and sometimes in agricultural areas with artificial irrigation in the milder climate areas (Grzimek 1990).

Valley pocket gophers have a body length of 11.5 to 30 cm, and a tail length of 4 to 9.5 cm. Males are considerably larger than females. One study showed that average male weight was 141 g, while females weighed 90 g ( Daly 1986). The fur is short, smooth, and soft. The underside fur is only somewhat paler than the dorsal. Many of the 185 subspecies aredistinguished by color, which varies from grey, to brown, to tan to almost black. Thomomys bottae has a robust body and has short legs with long front claws. It has small eyes and ears and a tail that is naked at the tip (Grzimek 1990). Pocket gophers are characterized by deep fur-lined cheek pouches, and the genus Thomomys is characterized by upper incisors that lack frontal grooves (Grzimek 1990).

Thomomys bottae is generally a solitary animal that "likes to dig" and spends a large portion of its life underground. The home range of T. bottae is about 150 sq. meters, but some animals wander 100 meters in search of more favorable conditions (Bandoli 1987). The burrow system that these pocket gophers create consists of deep permanent burrows and shallow tunnels used for feeding. The deep lodge systems are usually 1-3 meters below ground and can contain several nesting and storing chamber. The specialized chambers may be 20-250 cm in diameter (Grzimek 1990). The feeding tunnels radiate outwards from the central permanent burrows. These tunnels are 5 cm in diameter and 13 to 46 cm deep. The nesting chambers are cushioned with dried grasses, while the other large chambers are relatively bare and are probably used for the purpose of storing food (Grzimek 1990). Pocket gophers do not leave raised ridges above the ground like moles, rather they throw up fan shaped mounds of soil at the side of the entrances. The entrances are generally kept blocked with soil (Nowak 1991).

During the day, valley pocket gophers do not wander far from their burrow entrances, but at night they move out above ground to some extent (Grzimek 1990). The Valley pocket gopher was found to be most active during the afternoon and less active at night, and the species has been found to have an average of 16.1 activity periods during the day. In comparison to other geomyids, activity (measured by proportion of time spent away from the nest) was low at 18.8% (Bandoli 1987). They are active at all times during the year and do not hibernate (Nowak 1991).

Valley pocket gophers are solitary and territorial during times during the year except during the reproductive season. Territoriality decreases during the mating season of the spring, and rises in the late summer and fall.

Valley pocket gophers generally eat roots, bulbs, tubers, and occasionally above ground plant parts. When in areas inhabited by humans, valley pocket gophers eat cultivated crops. Thomomys bottae do not drink water and get their needs for moisture from "juicy" vegetable matter. Valley pocket gophers may eat plants above ground, but often times they burrow under the plant, bite off the roots and pull the stem into the burrow for further preparation. Once in the burrow, they cut the vegetation into smaller pieces and push it into the cheek-pouches with their front claws. When placed in the deep cheek-pouches, a large quantity can be carried to a storage or eating place.

Pocket gophers have large stomachs and caeca, and the amount of food that can be contained in the digestive tract at one time can exceed 21% of the animals total weight.

Although valley pocket gophers, along with other pocket gophers, are accused of damaging grasslands, overgrazing by domestic livestock does most of the damage. The gopher population is attracted by the conditions the livestock create (Grzimek 1990). Also, pocket gophers are considered pests in agricultural areas where they eat crops and cut the roots of young trees (Nowak 1991).

Valley pocket gophers are valuable to humans in many ways. The burrowing that the species does helps to keep the earth porous and (friable). The burying of vegetation enriches the soil. In mountain meadows, their holes allow runoff from snow to sink deep into then earth, conserving water and soil (Nowak 1991).

Thomomys bottae are not endangered.

Valley pocket gophers wear their claws down at a fast rate due to constant digging. In order to cope with this, the middle claw grows twice as fast as the other claws. (Grzimek 1990) Owls prey on them at night, and badgers, coyotes, and foxes dig them out of their burrows to consume them. The oldest tagged wild individual was 4 years old, but they usually do not live past their second year, possibly due to predation. Predation, though, does not have an effect on the species' numbers (Grzimek 1990).