Thomomys bulbivorus
Camas pocket gopher

Thomomys bulbivorus is found only in the Willamette Valley of Oregon (located in the northwestern United States). Blair (1957) ; Carraway (1987)

Thomomys bulbivorus is fossorial, found exclusively in the rich soil of the Willamette Valley in central Oregon. Carraway (1987) ; Blair (1957)

Thomomys bulbivorus is the largest member of the genus, at nearly 325 mm total length and 550 g. Like all members of the genus, T. bulbivorus has small ears and eyes, short legs, powerfully built shoulders, slim hips, fur-lined cheek pouches, and a nearly naked tail. The dorsum is a dark brown, and the ears and nose are tipped blackish. The venter is grey, with exception of a white patch on the throat. Winter pelage is long and soft, whereas summer pelage is short and coarse. Incisors are highly procumbent and protrude, with the lips closing behind them.

Carraway (1987) ; Parker (1990) ; Blair (1957)

The breeding season of T. bulbivorus extends from the beginning of April to early June. Studies suggest a range in litter size from four to nine. At birth, young weigh approximately 6g and are about 50mm long. The young lack hair, teeth, and pockets, although growth is rapid. By two weeks young begin to develop hair. At three weeks they crawl and begin to eat solid food, and by four weeks have formed cheek pouches. At five and six weeks respectively, they open their eyes and are weaned. Sexual maturity is attained by the breeding season following birth. Carraway (1987)

Thomomys bulbivorus will defend their territory and themselves aggressively. While their fighting ability is reknowned, they flee from opponents if the opportunity arises. Individuals of this species are generally solitary, except during the mating season when males enter the burrow systems of females. The most common activity of these pocket gophers is the excavation of underground tunnels as a means of foraging. Due to the hardness of the soils, most excavation is accomplished through use of the procumbent incisors. This loosened soil is then pushed out the entrance, forming a characteristic fan-shaped mound.

Carraway (1987) ; Nowak and Paradiso (1983)

Most sounds made by this species are produced by the teeth, usually a 'chatter' or 'grinding' sound. However, when males and females are placed together, a 'crooning' sound can also be heard.

The diet of T. bulbivorus consists of roots, bulbs, leaves, cultivated crops, and other vegetation. While they may procure plants that grow above ground when they come out at night, they more often burrow under the plants, bite off the roots, and pull the stems down into the burrow. This vegetation is then cut into smaller pieces and pushed into the fur-lined cheek pouches with the front claws, eventually to be carried to a storage or eating place. Nowak and Paradiso (1983)

Pocket gopher are in many ways valuable to humans. By tunneling, they keep the earth porous and friable. Furthermore, they keep the soil rich by burying vegetation. Also, their burrows serve to conserve both water and soil when the snow melts (the resultant runoff enters the gopher burrows). Nowak and Paradiso (1983)

In agricultural areas these animals are considered pests because they eat crops, cut the roots of yound trees, and can cause local flooding by tunneling through dikes. Nowak and Paradiso (1983)

While this species is only found in the Willamette Valley of Oregon, it is relatively common there, and thus has no special conservation status. Carraway (1987)

The generic name Thomomys arises from the Greek roots, meaning 'a heap' and 'mouse.' The specific name bulbivorus comes from the Latin meaning 'bulb-eater.' Carraway (1987)