It was the smell that gave it away.
Sonoma County Reptile Rescue director Al Wolf had been called out to a home in Santa Rosa, California, after the owner noticed snakes coming and going from the foundations underneath her house.
As he was led under the property with a flashlight, bucket, hexarmour gloves and 24-inch snake pole, he first noticed the thick musky stench that reptiles emit when they sense danger.
“Within a minute I saw my first rattlesnake, and then I saw a second rattlesnake. Every three to four minutes I would find another snake.”
Just over three hours later, Mr Wolf had pulled out more than 80 rattlesnakes, 59 babies and 22 adults.
He’s since gone back to the house twice more and retrieved another 11 snakes.
After 30 years as director of Sonoma County Reptile Rescue, Mr Wolf is well accustomed to handling rattlesnakes. But the most he had previously come across under one home was six snakes.
“I’ve never had a find like that before,” Mr Wolf told The Independent.
“The owner did make a little remark to me that she knows why she hasn’t had a rodent problem.”
Mr Wolf said he enjoyed rescuing rattlesnakes, but after being bitten 13 times, he had a healthy respect for them.
“I’m pretty gentle about it, I like them, I’m not going to hurt them. You get a few that don’t want to be touched, but I do this literally everyday.
“I don’t consider it dangerous because it’s what I do all the time, but I do have respect for them.
“I don’t want to get bit again.”
The house had an unsecured foundation, so animals could access underneath the house, and being in a rocky area of Santa Rosa, it was a perfect nesting ground for the snakes.
They like curling up in warm dens and will return to the same location year after year, Mr Wolf says.
“I’ll be going out there again because October is the month that they’re all going to come back in for hibernation, so there are probably more snakes under there.”
After retrieving the snakes, Mr Wolf relocates them to ranches around northern California as pest control.
The homeowner, a woman in her 80s who lives alone, asked to remain anonymous as her neighbour likes killing snakes, Mr Wolf said.
Sonoma County has been devastated by fires over the last few years, with 7,000 homes being lost.
Rattlesnakes try to avoid contact with humans, but Mr Wolf said the fires had forced the snakes to come closer to homes as they look for places to hide.
About 8,000 people are bitten by venomous snakes in the United States each year, with 10 to 15 deaths, according to the Food and Drug Administration.
Rattlesnake bites can be fatal, but are treatable with anti-venom.