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Mazama Pocket Gopher
This is a pocket gopher you are not allowed to kill. Four subspecies of the Mazama pocket gopher have been federally Threatened under the Endangered Species Act since May 2014, and every Mazama pocket gopher subspecies in Washington has been listed as Threatened by the state since 2006. Those two protections stack, and they do not cancel each other. That makes this animal the exact opposite of Botta's pocket gopher, the animal most people picture when they hear the word gopher, which is an unprotected nongame mammal across most of its range and can be trapped on sight. Same family, same fan-shaped mounds, same chewed roots, completely different legal answer. The listed subspecies live nowhere else on earth but the glacial outwash prairie remnants of Thurston and Pierce counties in Washington's south Puget Sound, on soil laid down when the last glaciers pulled back 10,000 to 12,000 years ago. An estimated 95 percent of that prairie is gone. The real risk for a homeowner is making a mole-trap decision about a federally protected rodent. A fresh mound on a Thurston County parcel is usually a permitting question before it is a wildlife question.

Seasonal Timeline

Mazama pocket gophers are active every month of the year and around the clock. They do not hibernate. What changes seasonally is how much dirt appears on the surface, and that tracks soil moisture: mound building in western Washington rises noticeably after the first significant fall rains and drops off in summer when the ground bakes hard.

Peak, Every regionMar–Jun
Peak, Every regionSep–Oct
JanFebMarAprMayJunJulAugSepOctNovDec

Mazama pocket gophers are active every month of the year and around the clock. They do not hibernate. What changes seasonally is how much…

There is no closed season on this animal, because there is no open one. The gopher is awake and underground twelve months a year, with activity spread across the full 24-hour day and a measured peak in late afternoon to early evening. Digging stops only when soil is frozen or fully saturated. Under normal field conditions a gopher tunnels at about 1.5 centimeters per minute, and Oregon animals were measured tunneling 4.8 times faster in soft, moist soil than in hard-baked ground.

The surface calendar and the underground calendar are not the same thing, and that trips people up. Mound building in western Washington is highly seasonal and picks up after the first real fall rains. A property that looked gopher-free all August can show a scatter of fresh mounds in October without a single new animal arriving. The reverse error is more common and more expensive: concluding in July that the gophers left. They did not. They are simply not producing surface soil, because short foraging tunnels dug in dry weather get backfilled into unused chambers instead of pushed up top.

One litter a year, and that single number is the whole demographic story. Federal materials note that unlike most small rodents, and unlike other kinds of pocket gopher, Mazama pocket gophers produce only one litter a year. Sexual maturity comes at about a year old, which is late for a rodent. Botta's pocket gopher on irrigated ground can produce up to three litters a year. A population that breeds once, matures slowly, and lives on scattered prairie remnants cannot absorb losses the way a yard gopher in California can, which is a large part of why one is listed and the other is not.

Where They're Found

This is a Pacific Northwest animal, and the honest version of the map is drawn in counties rather than states.

The species as a whole lives in three states and nowhere else. Thomomys mazama is found only in western Washington, western Oregon, and northern California. The Olympic Mountains of Washington are the northern limit of the entire species range.

Washington is where the legal protection is, and it is west of the Cascades only. Washington's own wildlife agency puts the species in Thurston, Pierce, Mason, and Clallam counties. The four federally listed subspecies are narrower still: the Olympia pocket gopher (T. m. pugetensis), Tenino pocket gopher (T. m. tumuli), and Yelm pocket gopher (T. m. yelmensis) are endemic to Thurston County, and the Roy Prairie pocket gopher (T. m. glacialis) is endemic to Pierce County. Critical habitat, designated the same day as the listing, totals about 1,607 acres, all of it in Thurston County: 676 acres for the Olympia subspecies at the Olympia Airport unit, 399 acres for the Tenino subspecies on Rocky Prairie, and 532 acres for the Yelm subspecies across the Tenalquot Prairie and Rock Prairie subunits. The Roy Prairie subspecies ended up with no final critical habitat at all, because every proposed acre of it, 4,840 in total, sat on Department of Defense land at Joint Base Lewis-McChord and was exempted.

Oregon and northern California hold different subspecies, and none of them are federally listed. The Washington restrictions do not apply in those states. Oregon's wildlife agency runs the animal as the western pocket gopher and maps it from the Columbia River south to the California border in the Coast Range and along the coast, plus the Cascade Range with eastward extensions to Mosier, Paulina Lake, and Merrill in Klamath County. The species is more widespread in Oregon than in Washington. California's own life history account calls it a common, yearlong resident of meadow and grassland habitats in the Klamath and western Cascade ranges. Anyone outside Washington should stop and check with their own state wildlife agency, because the answer there is different.

On the ground, look at the soil, not the map. This animal needs loamy sand or sandy loam. Federal materials name both failure modes precisely: clay and highly silty soils are too wet, too hard to dig, and not permeable enough, while extremely sandy soils will not hold a tunnel's shape. Very rocky ground is out, and so is grassland taken over by dense Scotch broom. Occupied sites in south Puget Sound include conserved prairies, pastures, grassy airport margins, Christmas tree farms, and occasionally clearcuts. Federal survey work scored Thurston County soils by how often gophers actually turned up in them: Nisqually loamy fine sand on 0 to 3 percent slopes came out highest, followed by the Spanaway-Nisqually complex on 2 to 10 percent slopes, Nisqually loamy fine sand on 3 to 15 percent slopes, and Cagey loamy sand. Thurston County alone holds 149,935 acres of the relevant soils, and the county's permitting maps carry them forward as More Preferred and Less Preferred gopher soils. Soil texture also sets local density: about 9 gophers per acre was measured on 22 acres of loamy sand at the Olympia Airport, against about 2 per acre on roughly 70 acres of gravelly soil at Weir Prairie.

How much of that ground is left, with both agency figures rather than one. Washington's own recovery plan states that more than 90 percent of the historic prairie and savanna has been converted to agriculture or lost to urban use, and names urban development as the single largest cause at 33 percent. Federal materials put it slightly higher, estimating that 95 percent of the prairie and grassland habitat this gopher depends on has been converted or developed. The two figures come from two agencies, and both are worth knowing rather than only the more dramatic one. What is left is fragmented, and the remaining pieces are separated by distances a gopher either cannot cross or will not.

Two absences confirmed rather than skipped. No published account places any pocket gopher in Alaska or Hawaii. The family is entirely continental North American, and every range description found for this species stops at western Washington, western Oregon, and northern California.

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