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Pacific rattlesnakes may benefit from climate change on the Central Coast

Hayley Crowell
Cal Poly researcher Hayley Crowell in the field

Now, in the heat of summer, warmer temperatures on the Central may not be comfortable for everyone.

But, a new study by a team of Cal Poly researchers found that Pacific rattlesnakes actually enjoy warmer temperatures and are more suited to conditions brought on by climate change.

Credit Hayley Crowell

The research team used temperature loggers to measure the body temperatures of Pacific Rattlesnakes.

“By using a series of temperature loggers throughout the environment and temperature loggers that were surgically implanted into snakes we [were able to] get snake body temperatures. We found that a majority of these rattlesnakes are existing at temperatures in environments that are lower than their preferred body temperatures,” said snake evolution and physiology expert Hayley Crowell.

Crowell said the team used a temperature gradient to allow rattlesnakes to choose a comfortable body temperature.

“One end is really hot and one end is really cold, you let the snakes move back and forth until they find the temperature and place they are happy at. In the lab, they chose temperatures that were around 85-86 degrees fahrenheit,” Crowell said.

Crowell said snakes in the wild have lower body temperatures than they prefer. For example, a Pacific rattlesnake on the coast has an average body temperature of 70 degrees, while inland Pacific rattlesnakes run a bit warmer at 74 degrees.

“Warming climates might allow them to thermoregulate to body temperatures that they actually want to be at,” Crowell said.

According to Crowell, warmer climates can lead to a longer active season for snakes — which is beneficial for the species’ survival.

Credit Hayley Crowell
Hayley Crowell

"They can come out of hibernation earlier which means more opportunities to find feed, more opportunities to find mates. It increases their active season overall,” Crowell said.

But for residents, Crowell said, this will not lead to a noticeable increase in the rattlesnake population.

“Does this mean there are going to be a ton more rattlesnakes? Probably not. Will it help them immediately become warmer? Maybe. Honestly, I don’t think anyone is going to see a giant increase of snakes in their backyard in the next 10 years,” Crowell said.

Crowell believes pacific rattlesnakes are important to our ecosystem and that they are not as dangerous or aggressive as most people think.

“In California they are very important. These pacific rattlesnakes coevolve with the ground squirrels that everybody detests. They live in yards, dig things up, and ruin foundations. Pacific rattlesnakes are their number one predator. They play a big role in maintaining the ground squirrel population,” Crowell said.

“They have no idea that we are not predators. They do have venom but they don’t want to use their venom because they can’t constrict. The only way they can get food is to have venom so if they waste it on someone messing with them they can’t eat,” Crowell said.

To learn more about Pacific rattlesnakes, and how to safely remove them, visit the Central Coast Snake Services website at

Corrected: April 15, 2022 at 4:22 PM PDT
An earlier version of this story referenced "rattlesnake bite temperatures" when it should have read "rattlesnake body temperatures." The text has been corrected.
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