Usually the pocket gophers I see are dead – brought in by one of our cats or trapped when they begin to burrow in lawns. Occasionally a gopher will pop its head out of its burrow, but never long enough to photograph. Therefore I was delighted last week to find this pocket gopher eating clover and digging on the surface of the soil in Golden Gate Park (along Martin Luther King Drive, San Francisco).
There are several species of pocket gophers in the Pacific Northwest, all belonging to the genus Thomomys. Some gophers are difficult to identify, separating the species depending on such specific characteristics as the shape of the baculum (bone in the penis). However, relying on range, I believe the pictured pocket gopher to be a Botta pocket gopher (Thomomys bottae).
Pocket gophers are fossorial (burrowing) rodents with fur-lined cheek pockets (the pocket of its name) and short tails. The fur is often similar to the color of the soil in which it is living.
A solitary animal, except during the breeding season, a pocket gopher makes a system of burrows large enough to supply its food. A young animal will create about 200 sq ft of burrows while an old, established female may have a burrow system of 2,000 sq ft. The earth mound of a gopher has a “plug” of soil at its center or side, distinguishing its mound from that of a mole.
Pocket gophers eat earthworms, grubs, roots, stems, leaves, bulbs and underground vegetables, such as carrots or radishes. Many is the gardener that has lost all their tulips or root vegetables to a gopher.
Pocket gophers have several adaptations for their lifestyle of digging and burrowing:
- small ears and eyes that do not become clogged with soil,
- sharp claws and heavy shoulder muscles for digging,
- small hips so it can turn quickly in the burrow,
- lips that close behind the teeth so that soil does not enter the mouth, and
- incisors that can bite off chunks of soil or roots. (The incisors grow approximately 11.5″ per year and wear down rapidly with use).
Although people become upset when gophers ruin a manicured lawn with their mounds and burrows or devour a vegetable or flower garden, these rodents are beneficial. They aerate the soil with their digging, the burrows capture rain and snowmelt and the burrows provide habitat for other species of mammals and reptiles.
There were no other nearby gopher mounds and this gopher was alternately digging and eating clover. Leonard and I theorize that it was a young gopher attempting to establish its own territory. Hope it now has a permanent home in the park.