In 1946, the story goes, a man stood in his field and marveled at an emerging mountain that had not been there the previous day. In 24 hours it had grown from a hole in the ground to a pile the size of a small house. Over the next decade it grew until it was about 1,300 feet high. Then it stopped growing.
The new mounds I keep finding in the yard do not billow sulfur and volcanic ash, and so I suppose none of them will grow to the size of Paricutín. They are composed of finely churned soil, six inches high at the very most, and no warmer than the surrounding air: certainly nowhere near lava-hot.
I know the culprit, though I have never seen it once. A mole would leave obvious tunnel mounds running just beneath the surface of the earth, and we have none of those, so it is not a mole. I was hoping, the first couple years we lived here, that I’d venture out one warm night and discover the pile-builder was part of a disjunct population of Aplodontia rufa, the vanishingly rare native “mountain beaver.” Not only would this be a very cool thing, but it would probably make sure the field behind us never got built on, as Aplodontia are a threatened species. But no: no mountain beavers are in evidence in our yard.
That leaves pocket gophers, rat-sized vegetarian rodents that burrow deeper than moles, and thus leave no obvious runs above ground. But which pocket gopher? Five species of Thomomys live in California, and had I a specimen in hand, distinguishing among them would be a painstaking manner of measuring ear lengths and hind foot ratios then comparing the measurements to vague and variable descriptions in a field guide to pocket gophers, which I would have to find in my shelves.
And I don’t even have a specimen. But I do know where I live, which helps. Or perhaps I should say I know where I don’t live. I don’t live in the Modoc country up by Lava Beds and Alturas, for instance, which eliminates the Townsend’s and northern pocket gophers (Thomomys townsendii and T. talpodes, respectively) from consideration, as their range overlaps the state of California there and nowhere else. My lack of residency in the Sierra Nevada or the west side of Mount Shasta likewise eliminates T. monticola, the mountain pocket gopher, and T. mazama, the (you guessed it) Mazama pocket gopher, lives in California only in the Klamath Siskiyou region, which I do not. Thus we identify this elusive denizen of the dirty deep as Botta’s pocket gopher, Thomomys bottae, whose range encompasses much of the Western United States including, I am sad to relate, that part of the Western United States occupied by my vegetable garden. “Are you sure you don’t want to line the bottom of those beds with chicken wire?” Becky asked three years ago in a not unannoyingly prescient fashion. “No, it’ll be fine,” I assured her. To her credit she only reminded me of the conversation twice or three times as I bought chicken wire a month ago to insert beneath a ton of garden soil.
The chicken wire lies still in a roll next to the fence, and that is fine, as the pocket gopher has moved on from Thistle’s parsley to the lawn and native plant beds. I don’t mind this as much.
I refer to the gopher in the singular with some justification. Botta’s pocket gophers live solitary lives until it comes time to breed. Still, breeding takes place over about half the year, from late winter until summer, and according to my copy of Baby’s First Guide to Geomyid Rodents of the Pacific Slope
The mounds are not exit holes: I’ve poked through more than a few without finding any doors or passageways. The piles apparently serve as earthen plugs for newly excavated runs, of which each individual burrow may have several in a tesselated, branching arrangement. The gopher — named, incidentally, by 18th Century voyageurs for the holes they dug in the landscape: “gaufre de miel” is French for “honeycomb” — do exit their burrows to eat, but only barely. At times a gardener will find a hole in the ground with a bare spot surrounding it whose radius is exactly one gopher length. The rodent keeps at least the tip of its tail in the burrow as it eats the foliage, so as to afford easy escape back into its hidey hole should the neighborhood barn owl or white tailed kite swing by, and believe me, both of those raptors make regular forays over our yard. Though the owl might be more interested in Thistle.
Gophers also eat below ground, either by finding convenient sub-surface corms or tubers, or by grabbing ahold of a plant’s taproot and just yanking it down under, which is what happened to Thistle’s parsley. Eating under the sod roof is good protection from the raptors. It doesn’t work so well, of course, against the predator I keep considering releasing into the yard, Pituophis catenifer catenifer, a far more rabbit-friendly gopher control mechanism. The neighborhood feral cats might harass it, but I have a plan there too.
But not just yet. The mounds of soil are occasionally annoying, and I do wish I didn’t have to bury fussy little chickenwire cages so that I can grow parsley and carrots, and I don’t even want to think about what happens when he chews through the PVC water line I buried three years ago. But our yard is about eight inches of topsoil laid down by oak trees and grasses on a gigantic hunk of rock, which I reach at most a shovel’s blade down in most spots. It’s diatomite, a soft sedimentary rock laid down in a deep ocean trench about 13 million years ago, and I’ve worked clays that were less amenable to being broken up with a pickaxe. Still, it’s rock, and the pocket gopher is tunneling through it with teeth and claws, making tunnels and slowly mixing the soil into it and vice versa, improving my drainage and increasing the nutrient content of the soil.
A garden that rototills itself: that’s worth a carrot or two.
Besides, just because it’s out of my control doesn’t need I mean to stop it. Salamanders make their homes in the burrows as well, which I like. And there’s the mnemonic factor to consider. Those mounds that spill mud out onto the flagstone are mere reminders that my garden, with its blossoms and mosquitoes, orbweavers and Steller’s jays, does not stop at the surface of the soil: it conducts its own business beneath my feet, tucked away out of sight and without my interference. The earth stirs beneath me. Why would I ask it to stop?
Note:Many old comments were lost in a database crash in 2008. Some conversations may seem to make less sense than they would have. A few will make more sense now.
8 comments on "Thomomys bottae"sadly, i think your little rodent, or its cousin, ran afoul of our dogs yesterday. the dogs were really proud of their prize, and after the corpse display had moved 20 feet closer to the door, i felt it was time to give it proper goodbyes.
this critter was rat-sized, but low to the ground and broader, with a pointy snout and protruding teeth, greyish color, and its feet were far broader than a rat’s [the upturned paws looked to have pads, like a kitten’s]. also, just a stump of a tail. forgive me, that’s all i could observe without freaking out about the corpse, and where it might move next.
plus they’re cute.
you might want it to stop if you waited thru the rain for the Canterbury bells - watched the plants fill out, watched the buds swell and form, watched them show a hint of sky blue petal and watched the miserable freaking gopher yank the entire plant down under the ground RIGHT at that moment, RIGHT before your eyes…. yep, that might have been the moment you would have asked it to stop at the top of your lungs. Just a hunch.
Very cool little essay, especially to this fan of the University of Minnesota Golden Gophers.
A garden that rototills itself: that’s worth a carrot or two.
I like that sentiement a lot.
Maybe you could find someone (you may know someone who knows someone) that has one of those cable video camera with tiny LED light. Many septic system companies use them, as well as security firms and lots of others, since they are now relatively cheap. It might be very cool to run the cable down in the shafts and check out the architectural achievements of your parasitic guest (fine line between parasitic and symbiotic balances i suppose on what it eats).
The sick twisted part of me loves to watch the hawks catch and eat the little buggers at our local arboretum park; and it seems to be too rare these days, as more and more rodents are thriving in this ever warmer northern landscape.
In my experience, you won’t find them eating through PVC piping, rather, you will find them creating tunnels directly below the pipe. Perhaps it’s the solid structure that won’t cave in above them, or the fact that gardeners won’t dig the tunnel out.
I will cage very special plants before I place them in the soil, but caging large beds proves to be ineffective. I’ve seen gophers on the surface many times. Guess what happens when a gopher gets caged in with your veggies? ;)
Gopher snakes are wonderful, but have such a slow metabolism to do much work controlling gopher populations. A note on gopher snakes, or any snakes at all: do not relocate them. Snakes get lost when outside their home ranges.
Garden cats are nice for rodent control, but they eat birds.
Besides raptors, my favorite garden animal is the Great Blue Heron….especially one standing directly over a gopher hole with a bloody beak.
Bioturbation rules….go gophers go!