What’s In That Hole?

At Ocean Beach earlier this year, around 250 people convened for a Hole Party, at which they dug holes in the sand just for fun. It was a reminder that only humans dig pointless holes; everyone else has a good reason. If you want to know what is in that hole on the side of a trail, what made it, or why it is there, get to know the diggers.

The question of what is in the hole has bedeviled me for as long as I have been taking walks. See, for example, the countless pictures of holes on my phone, which are as photogenic as you’d imagine and mostly annoyingly anonymous. So I recently dove, like Alice, down the rabbit hole that is the subject of holes.

A deep, uncomfortable truth up front: You’ll never know what’s in all the holes. If you disregard good sense and search the internet for information about holes, you’ll find that much of the obsessive content is by people aiming to evict or kill whatever is in the hole, because it is in a lawn or an orchard. Iowa State University published a flowchart indicating that when you find your sod neatly rolled up, you’ve got skunks, but if you find an inch-high chimney of soil above the sod, it’s crayfish. 

But holes in wild places have too many variables for a flowchart. Garth Harwood, a tracker and retired outdoor educator in the Santa Cruz Mountains, says to first ask yourself whether the hole is even worth investigating. If it is old and weathered, it has probably been through a lot and seen multiple users. “That’s not a hole that’s going to give you any satisfaction,” he says.

Assuming you have a fresh hole—sometimes evidenced by damp, fluffy earth—how big is it? Use a ruler, if you hope to get down to species. But even then, writes Mark Elbroch, author of Mammal Tracks & Sign: A Guide to North American Species, “differentiating the holes and burrows of small mammals is incredibly difficult.” Underscoring this point, a page of black polka dots shows the diameters of various animals’ burrow entrances. My main takeaways: (a) gosh, there are so many rodents, and (b) hole sizes overlap quite a bit. Still, it’s a start. Badgers and coyotes make some of the biggest ones in our area, though ground squirrels sometimes make such grand entrances that they are mistaken for the works of larger animals. Invertebrates make the smallest: ants, wasps, native bees.

Harwood ticks off more physical attributes to ponder—the shape of the hole, for one. Skunks use little sharp paws to dig little shallow conical holes; the cone’s tip marks where the insect was, until it got eaten. Then there’s the angle of the tunnel, if there is a tunnel. Elbroch notes that the dens of kit foxes angle sharply down, out of sight. Consider whether the dirt was pulled out from above or pushed out from below, and what kind of body did it. A stubby-legged badger digs at a shallower angle than a long-legged coyote. A broad-footed mole’s skeleton is wholly made for hole life, allowing it to dig with either a breaststroke or a crawl stroke (and its fur grows in such a way that the mole can go backward and forward in tunnels, like train cars, without being rubbed the wrong way). The main consequence of being so perfect a tunnel dweller is that one has little reason to surface, so molehills are mainly all you see of moles. More considerations: What kind of dirt has been cast aside in the making of the hole (called a “throw mound”) and in what pattern? What else do you notice? The essential existential question is why the hole was made.

Or why it is being occupied, since many hole-users are renters. Burrowing owls duck into ground-squirrel tunnels for cover and perch atop badger mounds to survey for voles. Muskrats may join beavers in their lodges, presumably to avoid extra work. And, says Harwood, “Any hole can be a snake hole.”

A methodical approach to hole investigation has its limits. “The thinking tends to come later,” says Meghan Walla-Murphy, a North Bay tracker. “I’m just trying to be there.” Thinking brings human assumptions: “How do you get yourself to observe rather than needing to name it right away, or photograph it?” Try drawing, she suggests. Be an antenna, taking in details that are part of a natural system too complex to understand completely. Eventually, your brain may sort some of it out. This can take years of gestation and many return trips. Richard Vacha, who has run the Marin Tracking Club for 20 years, calls such puzzles that park in his brain his “sacred questions.” One mystery hole on his current list is a small circular kind that appears near packed-dirt trails with no throw mound, backfilled up to the surface. Gophers? Voles? He doesn’t need an answer immediately.

Vacha takes me out to a grassy field that doesn’t look like much, located next to the Abbotts Lagoon Trail at Point Reyes National Seashore. It’s one of the spots he keeps his tracker’s eye on. A closer look reveals a riot of tiny springy things shooting up amid the crenellation of cattle hoofprints: indigo lupines, fuzzy emerald yarrow, maroon docks. And everywhere there are holes. This place ought to come with an ankle-sprain warning sign. Honestly, this is the real Hole Party. Gopher, mole, badger, skunk, weasel. No signs of voles, which worries Vacha—voles are foundational meals for many—and it seems like that might make the sacred question list.

Under the field is a multilayered labyrinth, whose general structure Vacha has gradually worked out. The voles (when present) make long toboggan runs through tall grasses that end in foot-deep nest holes, whose ownership you can confirm by scratching around for vole scat. Just under the surface, the moles snuffle around for earthworms in the humus; their nests are two feet down. Below the moles live the gophers, incessantly excavating their tunnels and nest, latrine, and food-cache chambers and scent-marking to fend off other gophers. Badgers hunt them all, creating big crescent-shaped throw mounds, the nearby grasses sometimes coated in dirt from all the furious digging.

Standing in this field I realize what makes holes so alluring. They are a window into a secret, complex underground world that we can never fully know, because it is a bad idea to stick body parts into most holes (see: “Any hole can be a snake hole”), and because we are too big to get into most of the holes. 

Usually. Vacha and I come upon a fresh badger hole that is deeper than the rest, too dark to gauge the bottom. A badger pressed its five-toed paws into the soft fresh mound, and a deer its hooves. Badger mounds attract all sorts. Vacha kneels, pokes a stick in. Snakes or scorpions don’t come around here, he says. He lies down. He sticks his whole arm in up to the shoulder. I take a turn and feel around, and I smell a faint sour musk. It is cool and cozy, bigger on the inside. A daybed, maybe. It feels intimate and maybe a little uppity to invite ourselves in. I think of something Walla-Murphy said: A hole is a home.

---

Some Notable Holes

How to distinguish some of our local diggers’ work, from bee holes to badger dens. 

Disclaimer: As a rule of thumb, do not stick your thumb, or any other part of your body, into a wild hole. It’s common sense, up there with not eating unidentified mushrooms and avoiding crumbly cliff edges.