On any Bay Area hike, snakes are likely closer than you realize. They lurk in gopher tunnels, hide under rocks, or bask in thickets just off the trail. Yet you probably won’t spot them—their survival depends on remaining hidden. So for nature lovers seeking a challenge, finding a rare snake is deeply rewarding. “Snake hunting,” says Emily Taylor, a Cal Poly San Luis Obispo biology professor and snake expert, “is the new birdwatching.”
The Bay Area is home to 25 different kinds of snakes. To maximize your chances of a face-to-face encounter, familiarize yourself with your target’s habits and preferences, just like birders do. Finding all our snake species may take years of effort. As a wildlife biologist and obsessive snake seeker, I’m still on the hunt myself. Here are some tips on getting started in different parts of our region: the Peninsula and Santa Cruz Mountains, the North Bay, and the East Bay.
Peninsula and the Santa Cruz Mountains
In this area, one hike may meander through redwoods, scrubby chaparral, oak woodlands, and shaded riparian canyons. It’s a mosaic of habitats with an array of inhabitants.
Years ago, when I started looking for snakes, I would open a field guide and flip to the range maps, glance at the shaded region for a species, and rush out, imagining that anywhere in that area could yield my target. I failed to consider microhabitat requirements. Microhabitats are the differing features across the wider landscape—rocky ridges, meadows, creeks. Each species has its preferred haunt. With no other snake is this as apparent as with the Bay Area’s flagship species, the San Francisco gartersnake (Thamnophis sirtalis tetrataenia).
Its range map includes nearly all of San Mateo County and a portion of Santa Cruz County, but you’ll never find it in the redwoods or chaparral. You have to think like a San Francisco gartersnake to find it. What do gartersnakes love? Frogs! What do frogs love? Ponds! The San Francisco gartersnake is rarely found far from water and its frog buffets.
The gartersnake’s alternating stripes of red, blue, and black, which stream down its back and flanks, have earned it an international fan club. “They’re kind of a legendary snake,” says Toby Sheppard-Wilder, a fifth grader and snake aficionado from Oregon whose family made a trip this spring to see these snakes. On a sunny morning in San Mateo County, Toby saw his first one, after just 15 minutes of searching. “I was really happy afterwards, for a long time,” he says. “Still am!!”
Toby’s winning strategy to find them (and mine as well) is to prowl slowly around pond margins, scanning vegetation at the edge for basking snakes. Go slow; despite their bright colors, they blend in well. When you see one, stay quiet and watch—not only to avoid disturbing an endangered species but because an unobtrusive approach has its own rewards. I once watched a gartersnake cruise along the edge of a pond poking its head into the crevices between matted tule. It caught nine treefrogs, choking each one down like popcorn in a matter of seconds.
The California mountain kingsnake (Lampropeltis zonata) is another looker on the Peninsula, with rings of maroon, cream, and black down its length. But it is no show-off—the kingsnake can be one of the most challenging of all local snakes to find, as it spends most of its time underground. It’s the Goldilocks of snakes, waiting for the perfect blend of conditions to come up and bask at the surface: recent rains and cool nights followed by balmy daytime temperatures. On warmer days, look in the morning. On colder overcast days, a ray of sunlight warming the rocks might bring mountain kings out from their underground halls. These kingsnakes can live for over 20 years, so if you see one, you may well cross paths again!
Red, white, and black-banded snakes are often said to have evolved their flashy colors to mimic venomous coral snakes. On its face, that doesn’t add up for our mountain kings, whose range does not overlap with that of coral snakes. How would predators learn to associate the color pattern with danger and avoid it? Researchers have championed various ideas. Perhaps the species’ ancestors’ ranges overlapped in the past. Maybe predators avoid those colors instinctually. Or maybe the colors give slithering snakes a ‘‘flicker effect,” making them harder to visually track.
North Bay
What do the rolling hills of Marin County have in common with the Amazon jungle? Boas! But while the Amazon’s enormous anacondas can swallow a capybara whole, here we have rubber boas (Charina bottae) that can swallow a baby mouse whole. Our boas can do something the giant constrictors of South America could never manage, though—survive in the cold. Ours are the northernmost species of boa, and while they don’t mind cool weather they do seem to require some moisture. They are rare or absent in dry areas like the Diablo Range. In the North Bay, they flourish.
On a blustery day in the Marin Headlands, as the fog burns away, the vegetation twinkles with dew, and the sun breaks through in patches—that’s when you might find a boa thermoregulating, maybe underneath a fallen fence post or a wind-whipped piece of cardboard nestled on a grassy hillside, as I once saw. That’s a perfect little safe house to warm up under without exposing oneself to predators like hawks or coyotes. If you find a boa, pause to appreciate how its skin looks several sizes too big and crinkles oddly along the curves. How its olive scales are unusually small and smooth to ease its movement through the soil. Then look at the head. Or is that the tail? Don’t worry, you wouldn’t be the first to confuse the two; in fact, this is the boa’s best defense. Facing a predator, or even an angry mouse whose home has been invaded (boas eat baby mice), the snake presents its tail for a bruising while hiding its head. That’s why older boas almost always sport scarred, knobbly tails.
Admire the boa, and then carefully put back its cover. Boas are slow-moving and slow-growing, and they return to the same favored spots to thermoregulate, so this could be the start of a beautiful friendship. A boa from Oregon was determined to be at least 55 years old—the longest recorded lifespan of any wild snake. Some of the boas in Marin’s hills could remember the moon landing or the dissolution of the Beatles, if boas cared about the things we legged creatures got up to.
East Bay
The dry, craggy hills of the Diablo Range in the East Bay are home to snakes that love heat and tolerate dry conditions. Hiking Mount Diablo, if you’re very lucky you could see the threatened Alameda whipsnake (Masticophis lateralis euryxanthus) living up to its name, chasing down an unfortunate lizard so fast that it’s a stripy streak. Just five populations are known to remain in Contra Costa and Alameda counties. In years of hiking the area, I have only seen one. More likely, you may see the area’s own garter, the Diablo Range gartersnake (Thamnophis atratus zaxanthus), diving into a cattle pond to chase tadpoles.
Northern California’s only dangerously venomous snake, the northern Pacific rattlesnake (Crotalus oreganus), is found in the Diablo Range in abundance—hence the warning signs at trailheads around here. A bit of caution is warranted, but no need to fear. Venom is costly for snakes to make, and they gain nothing by using it up on something too large to eat. Most venomous snakebites in the U.S. happen when somebody is harassing or trying to kill a snake. Pay attention to where you put your feet and hands, wear proper footwear, keep dogs leashed, and don’t mess with any rattlesnakes, and your chances of being bitten dwindle to the point that the cows you’ll pass on your hike pose a greater risk to your health.
Once you’ve braved the cows and made your way to, say, a rocky ridge, start peering at rock piles, especially sun-dappled ones that offer the residents in their nooks a nice temperature gradient. You might even find a rattlesnake den, a spot where rattlers overwinter. Usually it’s a deep fissure that offers insulation from temperature swings. These can be spots for various roommates of other species—gartersnakes, whipsnakes, racers, and gopher snakes have all lodged with rattlers. A tip from expert Emily Taylor: Look for a pregnant female in July or August. When it is too hot to lie in the full sun, “she may have just one loop of her body sticking out in the sun,” Taylor says. That’s “the loop that contains all her fetal rattlesnakes, with eight or 10 little baby snakes in there.” Mom is doing something that only snakes, with their long bodies, can do: By heating up a segment of her body, she speeds up her babies’ development.
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In fall, you may see the newborn rattlesnakes tangled up in a wad with their siblings, each as cute as a button, with only a single tail nubbin rather than a full rattle. They are no more dangerous than adult rattlesnakes, contrary to myth. Actually less so, because they have less venom. You may see their tired mothers nearby, deflated after giving live birth. Seeing their unblinking eyes and unwavering expressions, you might assume they’re unfeeling. But research shows that pit vipers form connections with their young and siblings. They’ll go their separate ways, then converge when they return to the den. And in difficult situations, rattlesnakes stress less with another snake nearby.
Rarely, you may see two males raising themselves off the ground, teetering as each tries to lift his head a little farther skyward than the other, shoving but never biting his rival. In this rattlesnake “combat,” the bigger snake typically wins by pinning the smaller and hopefully impressing any female rattlers nearby. But don’t count on seeing this on your first rattlesnake sighting or even your hundredth!
more RESOURCES FOR EXPLORing
Starting your snake journey
In the past year, California snake enthusiasts gained two new fantastic resources. California Snakes and How to Find Them, by Emily Taylor, is full of personal stories, natural history, and tips. California Amphibians and Reptiles, by Robert Hansen and Jackson Shedd—biologists with decades of experience investigating California’s reptile species—is a trove of range maps, identification keys, and info on every imaginable morph and variety of species. Both books are stunningly illustrated. Thanks to guides like these, there’s never been a better time to start looking for snakes. If you do, I hope you will come to love them, and look forward to even fleeting glimpses of a sinuous coil flowing into the tall grass beside a trail.
