Rattlesnake researchers raise vipers from the pits of human fear

FRENCHMAN COULEE, GRANT COUNTY – It was a sunny afternoon in May, the first hot day of the year in the Columbia Basin. For rattlesnakes, and the researchers who study them, temperature is everything – and J.D. Brooks was eager to make the most of a short season.

From late April to early September, when other outdoor enthusiasts are doing their best to avoid Washington’s only venomous snake, Brooks and his fellow graduate students at Central Washington University are on the hunt.

Their quarry is Crotalus oreganus, the Northern Pacific rattlesnake. Armed with snake tongs and 5-gallon buckets, the group taking to the field last month is part of a 30-year quest by CWU biologist Dan Beck to uncover the secrets of a creature that gives most people the creeps.

Beck and his students have staked out dozens of snake dens across Central and Eastern Washington. They’ve documented the species’ habits, developed ways to monitor growth rates based on rattle size, and deployed tiny transmitters to track the animals’ movements.

Among their findings is that Northern Pacifics are surprisingly mellow homebodies – with a social life.

Along the way, Beck says he’s also learned a lot about human nature.

“The science is fascinating, but as I get older I get more interested in people and the way we react to rattlesnakes,” he said. “They are a metaphor for what we fear.”

When he first started studying Washington’s rattlers, it was common for people to stomp any snakes they encountered and even destroy dens. That’s changed, and Beck hopes his efforts to introduce schoolkids, scout troops and civic clubs to the state’s sole rattler species have helped.

“You just sit down and talk with people about the amazing stuff snakes do,” he said. “When you take away the superstitions and stories and replace them with knowledge and understanding, you end up with respect rather than fear.”

As Brooks and graduate student Joey Chase collected their gear, they explained that the area where they were working on this day – a popular climbing destination called Frenchman Coulee – is home to two rattlesnake dens that Beck’s lab has been monitoring for years.

Atop a steep basalt outcrop, the students quickly spotted several of the brown, mottled snakes sunning themselves among the rocks.

A furious buzz erupted as Brooks plucked a young snake from its lounging spot, using 3-foot-long tongs to grab its head while maintaining a safe distance. He released the rattler on open ground and nudged it toward a narrow plastic tube.

Perhaps mistaking the clear cylinder for a hiding place, the snake slithered in. Brooks grabbed the tube, pinning the snake’s business end inside and leaving its tail dangling.

A series of swift, scientific maneuvers followed: The researchers measured, sexed and appraised the animal. They clipped scales for future identification and stuck a cotton swab in the cloaca – an all-purpose posterior orifice – to collect DNA.

Brooks, who’s studying coloration and camouflage, took photos to compare snakes from different areas.

After a harsh winter, the snakes had only recently emerged from their den, where as many as 50 hibernate en masse, Brooks said.

With a range that extends from California through Oregon, Idaho, Eastern Washington and well into British Columbia, Northern Pacifics are the world’s northernmost-occurring rattlesnake.

Except for rare hitchhikers, they aren’t found in Western Washington, but they do thrive in Oregon’s Willamette Valley.

Northwest winters are brutal for ecotherms like snakes, which are at the mercy of their environment when it comes to regulating body temperature, said John Rohrer, a U.S. Forest Service biologist who studies the snakes in the Methow Valley. Rattlesnakes can’t even digest a meal if they aren’t warm enough.

“I’m so intrigued by the idea that these animals could survive in an area where there can be freezing temperatures every day from September into April,” Rohrer said.

A good den is crucial, and most snakes use the same site year after year.

Dens, or hibernacula, are almost always on south-facing slopes, where the animals can soak up sun when they emerge from their chilly months of hibernation, Beck and his students found. The refuges must be deep enough to extend below the frost line, while also being sheltered from wind, rain and dripping snowmelt.

“They are pretty unique places,” said Rohrer, who collaborates with Beck and has mapped roughly 30 hibernacula in the Methow Valley. “I want to make sure we know where they are, so we’re not building roads or trails too close.”

Thermometers threaded into dens log winter temperatures as low as 40 degrees, Beck said. Recently, he and his students have also started implanting minuscule temperature sensors and radio transmitters inside some of their research subjects.

After Brooks and Chase were done on the cliff top, they headed for a den on lower ground. Chase hoped to find a wired-up male nicknamed Joselito.

He captured Joselito last summer, near a small marsh. “I haven’t seen him in a year,” said Chase, who is tracking snakes to see how forest fires affect foraging and survival.

As a kid, he says, he was afraid of snakes. But after keeping them as pets and working with wild populations, admiration took hold. “Now I just think they’re so cute, even when they’re coiled up and rattling.”

Chase started his college career at Cornell, but moved to CWU because it’s one of the few places where students can study rattlesnakes in the wild.

Near the second den, he unfolded a radio antenna and held it aloft like an umbrella, listening for the staccato beeps that would indicate Joselito was nearby.

Northern Pacific rattlesnakes have well-defined territories and rarely venture more than a mile from their dens, Chase explained.

Sure enough, he soon picked up Joselito’s trail.

As the beeps intensified, Brooks plucked the long, greenish snake from under a clump of sage.

By far the biggest catch of the day, Joselito is at least 10 years old, Chase estimated. Northern Pacifics can grow to 3 feet, and live more than 25 years.

Compared with other rattlesnakes, Northern Pacifics are also relatively mild-mannered. Maybe it’s because they live in a colder climate, Beck speculated. “They’re just less irritable, not as defensive.”

He and his team are also seeing evidence of more social interactions than previously expected. Beck recently set up a den-like exhibit at CWU with around a dozen rescued rattlesnakes. Two males, called Tickler and Bruce, hang out together all the time. Other snakes avoid each other.

Studies with related species show that females shepherd their offspring – which are born live – through their first few weeks, and that many snakes prefer to associate with their own relatives. Beck and his colleagues discovered that Northern Pacifics in Washington congregate at communal sites to shed their skins – perhaps because that’s when females get frisky and males want to be nearby.

The snakes might also be able to adapt to new surroundings, said Rohrer, who responds to calls from panicked residents with a rattler in the yard. He marks the animals, then moves them to more remote areas.

Recaptures show that at least some of the snakes survive the shift.

Northern Pacifics are a protected species in British Columbia, but not in Washington. The snakes help keep populations of mice and small mammals in check, while in turn are preyed upon by hawks and other predators. But the biggest threat they face is people and development, Beck said.

He teamed up recently with researchers at the University of British Columbia who are analyzing snake DNA to gauge the genetic health of Northwest populations, and to identify barriers – like roads – that block snake movements.

Northern Pacific rattlers don’t seem to be in peril in Washington – but researchers don’t have a good handle on the population as a whole, Beck added.

“Rattlesnakes are survivors,” he said. “Still, I’ve noticed that a lot of the dens over the years where we used to see a lot of snakes – we don’t see them anymore.”