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Rattlesnakes can calm down their friends, study shows

Photo by Cade Powell, BLM

  • Research reveals that rattlesnakes, like humans, experience stress reduction when in the presence of a companion snake, a phenomenon known as social buffering.
  • Stress can lead to hormonal changes, affecting the nervous system, immune response and behavior.
  • The study examined 25 wild Southern Pacific rattlesnakes in different scenarios, measuring their heart rate to assess stress levels and social buffering.
  • By controlling small mammal populations, rattlesnakes maintain ecosystem balance and also reduce rodent and tick-borne diseases. Yet, they often face threats from humans.

If you stress out a rattlesnake, make sure it has a friend around. Much like humans, stressed snakes are calmed by a companion’s presence, according to new research.

Stress can lead to increased hormone production, resulting in changes in the nervous system, immune response and behavior. Certain animals, like humans, can regulate their stress response when in the company of another animal of their species, which is referred to as social buffering.

“We showed that when two snakes were together and experienced a stressful situation, they could buffer each other’s stress response, much like what happens to humans when they endure a stressful event together,” said Chelsea Martin, a Ph.D. student at Loma Linda University and first author of the study published in Frontiers in Ethology.

Snakes can display complex social behavior, but the concept of social buffering in reptiles has yet to be extensively studied.

“This dampening of the stress response has not been reported previously in any reptile species,” Martin said.

The scientists examined how social buffering affected 25 wild Southern Pacific rattlesnakes (Crotalus helleri), also known as black diamond rattlesnakes, in three different scenarios: when the snakes were alone, in the presence of a same-sex companion, and in the presence of a rope as an inanimate control object.

The researchers used heart rate as a dependable indicator of acute stress levels and social buffering. They fitted electrodes near the snakes’ hearts and connected the sensors to a heart rate monitor. They then placed the snakes in a dark and enclosed testing environment: a bucket.

After 20 minutes, the researchers artificially disrupted the snakes’ environment. Martin then measured the increase in heart rate from the baseline, the time required for the heart rate to return to normal, and the duration of rattling exhibited by the snakes.

Rattlesnake with a rope serving as inanimate control object in the study. Photo courtesy of Chlesea Martin.
Researchers fit a heart rate monitor on one of the rattlesnake test subjects. Photo courtesy of Chlesea Martin.

The presence of a companion snake significantly reduced the change in heart rate, indicating less stress. The researchers worked with wild-caught rattlesnakes, demonstrating that social buffering most likely exists in nature and can carry on in captivity.

“Our test snakes came from populations that overwinter individually and communally. We found no differences in snake populations who did or didn’t overwinter in groups,” Martin said. “We also did not observe a difference in social buffering between the sexes.”

Rattlesnakes can be found throughout most regions of the continental United States, with a higher concentration in the Southwest, and are also present in Mexico, Central America and South America. While most rattlesnake species are doing well, one species and one subspecies of rattlesnake are officially recognized by the U.S. government as threatened.

Rattlesnakes play an important role in their ecosystems by controlling small mammal populations like rodents. By consuming these prey species, rattlesnakes play a vital role in preserving the overall health of different species and reducing the transmission of diseases from rodents to humans.

Despite their services, rattlesnakes risk being killed by people who perceive them as dangerous nuisances instead of recognizing their role as essential predators. This fear also has repercussions for species like gopher snakes, which resemble rattlesnakes and are often mistakenly killed because of a misidentification.

“Our results provide insights into social behavior patterns of snakes,” Martin said. “But it might also improve rattlesnakes’ image. In the public eye, they are often maligned. Our findings could help to change that.”


Martin, C. E., Fox, G. A., Putman, B. J., & Hayes, W. K. (2023). Social security: Can rattlesnakes reduce acute stress through social buffering? Frontiers in Ethology2, 1181774. doi:10.3389/fetho.2023.1181774

Banner image of rattlesnake by Cade Powell, BLM vis Flickr (CC BY 2.0)

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