August 16, 2019 Features & Images » Feature Story

The Long and Short of B.C.'s Snakes 

Learning about one of the world's least understood—and most threatened—animal groups

click to flip through (9) STORY AND PHOTOS BY LESLIE ANTHONY - The Long and Short of B.C.'s Snakes Learning about one of the world's least understood—and most threatened—animal groups
  • Story and photos by Leslie Anthony
  • The Long and Short of B.C.'s Snakes Learning about one of the world's least understood—and most threatened—animal groups

British Columbia is full of snakes. There, I said it. Some of you, mostly nature-minded people, will eagerly continue reading to learn something about one of the least understood—and most threatened—animal groups worldwide. Others will stop reading here, or at least want to. But even a few of those folks—maybe most—will continue anyway for much the same reason we read news about airline crashes and tsunamis: our fascination with low-probability threats overrules our fear of them. At least from the safety of the couch.

The reality is that snakes are only a threat to the worms and frogs and mice they feed on. And, of course, I'm exaggerating their ubiquity. Given our northerly location, British Columbia is hardly full of serpents, though at least one of our nine species can be found in abundance almost everywhere save the province's extreme northern reaches. The remainder—which also reach the northern limit of their ranges here—mostly populate areas of the southern tier, discontinuously distributed because of the labyrinthine nature of B.C.'s range-and-valley geography. The Lower Mainland (which boasts five species) and warm, southern Interior valleys (six species) harbour most of this modest diversity. But what our snake fauna lacks in variety is offset by its uniqueness: three colourful species of gartersnake; ancient, primitive species like the Northern Rubber Boa; large, agile hunters like the Great Basin Gophersnake and Western Yellow-bellied Racer; small nocturnal species like the Sharp-tailed Snake and Desert Nightsnake; and yes, even the undeserved bogeyman of every cowboy campfire, the Northern Pacific Rattlesnake.

Biologically speaking, snakes are fascinating creatures that date to the Jurassic period, approximately 150 million years ago. Though understood to have evolved through limb reduction in an ancient lizard lineage, it's unknown whether this was originally an aquatic or terrestrial adaptation—adding to the many mysteries and myths about snakes (a new book—The Origin of Snakes: Morphology and the Fossil Record, by Michael Wayne Caldwell, sorts through the various ideas). There may be a snake tie-in to our own origins as well. Some anthropologists believe that the high visual acuity of our primate ancestors evolved to detect snake strikes in their arboreal habitat. Meaning that we might have snakes to thank for the ability to see a frisbee approaching in our peripheral vision.

This article's purpose isn't to plumb evolutionary theory, however, but rather to celebrate the ecological importance of these animals, which provide major control on invertebrate, amphibian, fish and rodent populations in the wild, the latter representing a de facto ecological service to farmers in places like Pemberton, most of whom know that the more snakes on their property, the better.

Few who spend time in B.C.'s outdoors would not have had occasion to come across a snake crossing or sunning on a trail or road. While this causes consternation in some, others are thrilled with such encounters. Both should view these opportunities as special given the worldwide decline of these animals due to habitat destruction, persecution, and the inevitable increase in roadkill that comes with increased development. Eight of B.C.'s snakes are completely harmless, and while the rattlesnake packs a venomous bite, avoiding that danger is far easier than avoiding the danger of wasps or even bears. With that in mind, here's an overview of British Columbia's snake fauna. As I like to say, snakes are friends of nature, and any friend of nature is a friend of mine.

Ode to a Gartersnake

With more than 25 species in its continental clan, gartersnakes are the reptile most familiar to the North American public, found in virtually every terrestrial and aquatic habitat and at all but the most restrictive latitudes. They also populate children's books wherever a cute, chirpy snake character is required. Even if you grow up terrified of giant constrictors, skulking vipers, and swaying cobras, gartersnakes may still hold a place in your heart as innocent scions of the landscapes of youth. But they also have a more important function. Because most are food generalists who include frogs, tadpoles, and fish, they're of great utility in the transfer of energy between aquatic and terrestrial ecosystems. All gartersnakes bear live young and tend to den communally for winter—sometimes in high numbers.

Of B.C.'s three gartersnake species, the most familiar is the Common Gartersnake, which further divides into three subspecies: the Puget Sound Gartersnake of Vancouver Island, the Gulf Islands, and the southern part of the Lower Mainland sports bold, yellow (or greenish) dorsal and lateral stripes on a black background; the Valley Gartersnake adds prominent red sidebars and a red cheek patch to this combination; and a similar if more subdued look is found in the Red-sided Gartersnake near the province's eastern border. Although frequent prey to a myriad of critters from hawks to raccoons, Valley Gartersnakes can be up to a metre in length and 20-plus years old. Although Alligator lizards are probably the more abundant reptile in Whistler, the Valley Gartersnake is more familiar, found in all our parks and wetlands, denning in various rockpiles around the valley. Watch for them crossing roads and the Valley Trail, especially early in the morning when they head out hunting.

Those who spend time on B.C.'s coastal islands or in the Interior will also be familiar with the Wandering Gartersnake, which has a brown-to-olive ground colour with a weak yellow stripe and black dots that combine to create a checkerboard pattern. These highly aquatic snakes often fill the niche occupied elsewhere by watersnakes, swimming at will in cold freshwater or ocean and feeding heartily on fish. It also likes mice—which is probably why it's the most abundant snake in Pemberton, beating out the Valley Gartersnake. It's known as far south as Rutherford Creek.

Finally, the Northwestern Gartersnake of B.C.'s South Coast islands and Lower Fraser Valley is a species whose confounding variability is its hallmark, with all manner of background colour and a dorsal stripe that can be red, orange, cream, blue or even non-existent. Northwesterns are further distinguished from the other two gartersnake species by a small head and less-prominent neck. They feed mostly on the slugs and earthworms common to their moist, foggy habitats. This species is common around Squamish and southward, but has also been found in the Pinecrest and Lucille Lake areas south of Whistler, and more recently within municipal boundaries in the Callaghan and at Cal-Cheak.

Northern Rubber Boa

For those who fear snakes, the impressively docile, almost toy-like Rubber Boa might be the ticket out of your own personal Fear Factor. This olive- or chocolate-brown animal whose name derives from its playdough appearance is people friendly: it's small (adults rarely exceed 70 centimetres), sleepy and slow-moving (people tend to be freaked out by other snakes' jerky, frantic movements), and it never, ever bites. It's also ancient (males sport vestiges of rear limbs in the form of tiny spurs used for tickling females), nocturnal (with cat-like vertical pupils), long-lived (up to 70 years!), and engages in fascinating behaviours.

The first of these has to do with defence against larger predators: like most snakes, Rubber Boas release a fetid combination of feces, uric acid and anal musk when disturbed. If that doesn't do the trick, the snake might flatten into a coil and flash a bright yellow belly as a sort of warning. If all else fails, they contract into a ball with their head buried in the centre and the blunt, nondescript tail sticking out. As a result, it has been nicknamed the "two-headed snake." This last posture has a further utility in the Rubber Boa's pursuit of food. Curling through the netherworld beneath leaves and logs and rocks, it seeks out the nests of small rodents, preferentially inhaling any babies it might find; when it does happen upon a nest and starts to devour the helpless young, it keeps the mother rodent at bay by fooling her into thinking its tail is its head, which she then attacks. As a result, the tails of most older Rubber Boas are heavily scarred by the slashes of rodent teeth.

Rubber Boas hibernate in hillside dens and transit to valley bottoms in summer in search of food. Females give birth to between one and four live young every few years and often hang around the den until the young are born in August. Though rarely seen, Rubber Boas are common throughout the Pemberton Valley, north to the Upper Lillooet and south to Rutherford Creek.

Sharp-tailed Snake

This small, secretive, nocturnal burrowing snake is a phantom that comes and goes from many of the Gary Oak meadow and open-canopy forest edges where it's found; it might be encountered annually at a site for a few years in a row, then disappear altogether only to turn up again years later. Common in California and Oregon, there are scattered populations in Washington state and, until 2011, when a single mainland population was discovered in Pemberton, it was found in B.C. only on the Gulf Islands and the southern tip of Vancouver Island.

The 20-to-30-cm snake has a reddish hue with a dusty charcoal band along each flank and a belly uniquely adorned with black crossbands—like the stripes of an old jail outfit. Its head is quite small with no discernable neck, and it's thought to be a slug specialist. It never bites.

Like racers and Gophersnakes, the Sharp-tailed Snake is confined to warm, open habitats like south-facing slopes where ground temperatures rise enough to incubate its eggs. Unfortunately, humans like these same sunny places, which are undergoing rapid destruction by urban development across its range—including Pemberton—keeping this unique, unassuming creature atop both provincial and federal endangered species lists.

Northern Pacific Rattlesnake

Far from being the demonic desert hazard they're depicted as, rattlesnakes are actually pretty cool. These wide-bodied animals have dark blotches on a lighter background that become more like bands toward the tail, encircling the body completely. They possess a rattle, of course, a distinct neck, a wide triangular head, and vertical pupils—a combination of characters that readily distinguishes them from other B.C. snakes. Sit-and-wait ambush predators, rattlesnakes lurk along routes used by small mammals such as ground squirrels and packrats, alerted to the approach of food by heat-sensing pits located between the nostril and eyes. Like many other B.C. snakes, they bear a small number of live young in late summer.

Rattlesnakes are also cool in being the most reasonable form of dangerous wildlife given the lengths they go to be left alone: their first line of defense is remaining motionless (a naturalist in the Okanagan once told me that for every rattler you see, there are 10 you don't); if that doesn't work, they head for cover. If you surprise, corner or get too close to one, they issue an audio warning; they're reluctant to bite, and, when they do, often don't inject venom—about a third of all rattlesnake bites are "dry" because every drop wasted on defense is a drop stolen from food procurement. Thus, the Okanagan, Canada's fastest-growing region and home to hundreds of thousands of people, averages about two bites a year. And zero deaths. (See sidebar for more info.)

The issue, at the northern edge of the rattlesnakes' range, however, is that preferential winter den sites are located in the rocky scree of hillsides that are separated from lower foraging habitat by development such as housing and roads, bringing snakes and humans into increasing contact.

Great Basin Gophersnake

British Columbia's largest snake at up to 2.5 metres is the Gophersnake—so named for its extensive use of abandoned rodent burrows. Due to its size, colouration, blotchy pattern, and occasional habit of vibrating its tail in dry grass, it's also the species most readily confused with the Northern Pacific Rattlesnake—a situation compounded by that fact that the ranges of the two species have a 90-per-cent overlap in the Okanagan, Thompson, Nicola, Similkameen and Fraser River Valleys. This, unfortunately, has led to even greater persecution than the animal would normally encounter.

This large, wide-ranging, egg-laying snake with a checkerboard pattern on its belly may look intimidating but it is completely harmless, and the bigger the specimen, the more rodent control it can carry out—a boon to farmers wherever it occurs. These animals tend to be solitary, denning, as per the name, in ground squirrel burrows.

Western Yellow-bellied Racer

Also known as the blue racer, this is one of the most widely distributed snake species in North America, known for its speed, climbing ability and prominent eyes—all signs of an active, daytime hunter of small mammals and birds.

The colour is bluish grey, bluish green or brownish with a cream to yellow belly and chin. Like the Great Basin Gophersnake with which it shares its range, racers can grow to almost two metres in length, though individuals over a metre are rare. Juveniles tend to be tan or light brown with a dark, splotchy pattern, which often sees them confused with Gophersnakes or Rattlesnakes until they morph into the unpatterned adult look.

Racers are egg-layers, occurring in all the usual warm and dry southern valleys, but have also been found farther north and west than Gophersnakes, around Anderson Lake near D'Arcy—possibly expanding their range due to climate change.

Desert Nightsnake

The Desert Nightsnake has only been on the list of B.C. reptiles since 1980, when it was first discovered in the lower Okanagan Valley—Canada's only true desert ecosystem and home to more threatened and endangered reptiles than anywhere else in the country. To date, there have only been a few dozen records of this small, mottled, cat-eyed snake that likes to eat frogs, salamanders, lizards and the young of other snakes. As the name suggests, it's nocturnal, and thus, coupled with small size, not likely to be encountered by people. Where the Sharp-tailed Snake is a phantom that comes and goes from various sites, the Desert Nightsnake is a virtual ghost, almost impossible to find even where it's known to occur.

Critter Cautions

Most folks stumble upon snakes, but some (mea culpa) actually go looking for them. If you're the type that wants to understand these animals better, it's a harder learning curve than, say, birding. Birds are out in the open, draw attention to themselves by vocalizing, and, being able to fly away, aren't worried about much; snakes, like other small creatures, are into camouflage and hiding. A good place to expect to see these animals, however, are ecotones—areas where one type of habitat meets another—like the edges of fields and forests, along a marshy lakeshore, and human-disturbed areas like borrow pits and trail edges. Such areas also tend to concentrate the prey snakes feed on.

Snakes should be photographed, like other wildlife, at a distance that doesn't cause discomfort for the animal. Obviously, this is closer with small animals like snakes than it is with large mammals, but the same rules apply. Furthermore, all snakes—including rattlesnakes—are protected under B.C.'s Wildlife Act: it is illegal to kill, harm, or remove them from the wild.

Though many people get worked up about snakebite, it's not much of a hazard in this part of the world. On average, 20,000 people a year die of snakebite worldwide, most in sub-Saharan Africa and Asia, yet the decade average for the U.S. is 2.1 deaths per 7,000 to 8,000 bites annually—and even then, fatalities are mostly those with pre-existing medical conditions. In Canada, the stats are even better—one death per decade versus 3.3 each year from wasp stings.

Even though it's not the hazard it's made out to be, a large-scale study in North America showed two disturbing trends: first, venomous snakebites were overwhelmingly suffered by males ages 15 to 35, and second, the vast majority occurred on the lower arm or hands, indicating the snake was being handled. By not handling venomous snakes, you reduce the risk of being bitten by 99 per cent; the other one per cent can be meliorated by easily followed cautions.

When travelling in rattlesnake country, stick to clear, open trails and carry a walking stick for sweeping ahead in vegetated areas. If you encounter a rattlesnake sunning on a trail that you can't safely go around, use a stick longer than a metre to encourage it to move off. When scrambling in rattlesnake-prone areas, don't put hands or feet anywhere you can't see them—such as reaching up into rocky crevices or stepping over logs. If you hear a rattlesnake, stop and locate the sound. If it's close, allow the critter to calm down then back off. Once you're a good body-length away, you can generally go around it. If you encounter a dead rattlesnake, don't touch it—the biting reflex remains intact even after death. 

Nk'mip Cellars is North America's first Indigenous-owned-and-operated winery. Situated on a long bench overlooking Osoyoos Lake, the winery also boasts a Desert Cultural Centre that promotes heritage knowledge and a program to protect and restore habitat for species at risk—particularly snakes. Visitors can learn about the multiyear rattlesnake radio-tracking program and watch snakes being tagged with under-skin microchips or paint applied to rattle segments that enable wildlife managers to monitor populations and work out protection strategies.

Naturally (ha ha), there are several great online resources when it comes to snakes. Consult these for more information, range maps, organizations, and other links: the Canadian Herpetological Society (CHS): canadianherpetology.ca; and the Reptiles of B.C. official website: bcreptiles.ca/snakes.htm.

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