Some people might consider a single rattlesnake under their house one rattlesnake too many. OK, so how about, I don’t know, approximately 100?

Such was the situation for a woman in Northern California at the start of this month. Having seen rattlesnakes slithering under her house – set in the northeastern part of the town of Santa Rosa, edging into the Mayacamas Mountains – she called the non-profit Sonoma County Reptile Rescue for assistance.

Its director, Al Wolf, found several rattlesnsnakes on his first foray below the woman’s home. Returning with a pair of buckets, safety gloves, and a snake-grabbing tool, he soon discovered that those initial serpents were but the tip of the rattler iceberg, if you will.

“I kept finding snakes for the next almost four hours,” he told the Los Angeles Times.

He ultimately ended up extracting 92–yes, 92–northern Pacific rattlers from below the floorboards: 22 adults and 59 babies in the first go, then 11 more on a return crawl-about. A memorable day on the job, to say the least, given that the magnitude far exceeded anything Wolf had seen at a home before, though he’s found dozens of rattlesnakes congregated at single sites in the wild.

“I was tickled pink,” Wolf, who founded Sonoma County Reptile Rescue in 1989, explained to the San Francisco Chronicle. “It’s what I like to do, and I generally get a call and find one, maybe two rattlesnakes. But when you start finding stuff like this, I think, ‘Oh good, this is a really worthwhile call.’”

That many rattlesnakes piled under a house is unusual, but the aggregation itself isn’t. Gravid female Pacific rattlers often give birth at communal sites called rookeries, which are commonly rocky settings offering ready access to both sun-basking vantages and cool, shady hideaways. Thermoregulation is a top priority for these pregnant snakes, which, research suggests, may need to maintain a higher body temperature than non-gravid females or males. Wolf speculated that plentiful rocks left around the Santa Rosa house’s foundation probably made it particularly attractive to rattlesnakes.

Speaking to Live Science, herpetologist Emily Taylor of California Polytechnic State University noted that, for reasons not entirely understood, some female rattlers give birth alone in holes, while others congregate in rookeries. She said those rookeries in California tend to be situated at higher-elevation sites, which – along with the specific context – made the big clutch of rattlers in Santa Rosa noteworthy. “It’s not typical in California at low elevations to have that many snakes, and it’s definitely not typical for them to be under a home,” she told Live Science.

The ins-and-outs of rattlesnake rookeries – often, like the communally occupied “hibernacula” dens where rattlers overwinter, used year after year – aren’t fully known. A study in Wyoming on the prairie rattlesnake (a close relative of the northern Pacific species, with which it was once lumped) suggested that, while males and non-pregnant females often made fairly lengthy journeys from hibernacula to warm-season foraging areas, gravid females traveled much shorter distances to rookeries. The authors proposed that rookeries might boost reproductive success by allowing pregnant rattlers to more effectively maintain an ideal body temperature (including by huddling together), plus provide protection from predators and set young rattlers up auspiciously for denning and finding prey.

In the Live Science article, Taylor said it was also possible that female rattlesnakes gathering in rookeries might be related, with research indicating some version of babysitting goes on within them.

Like the rest of their clan, northern Pacific rattlesnakes – while unaggressive – are venomous. It’s understandable, therefore, why a homeowner might balk at the idea of hosting 90-odd of them underfoot. Wolf relocated the Santa Rosa rattlesnakes at various regional locations that Sonoma County Reptile Rescue uses for the purpose, including dozens of known snake-denning areas and ranches and other properties whose owners desire some natural rodent control. According to media reports, he planned to make a followup visit to the house in question this month to check for stragglers, and also return in the spring in case freshly emerged rattlers were again beelining for the home’s nether regions.

(Oh, and bonus, at least as far as the homeowner was concerned: The San Francisco Chronicle reported that, in his quest to round up all of those subsurface rattlesnakes, Wolf also found and removed some long-expired opossum and cat remains. All in day’s work.)

Header image: Ken-ichi Ueda