Having a Companion Could Help Rattlesnakes Stay Calm

During a stressful event, snakes experienced a smaller spike in heart rate when they were in the presence of another snake, according to a new study

A southern Pacific rattlesnake slithers over a finely rocky surface with its tongue out
A southern Pacific rattlesnake. Previous studies had found examples of companionship reducing stress in birds and mammals, but not reptiles. David McNew / Getty Images

When rattlesnakes are in the presence of a companion, they’re more resilient to stress, according to new research published this month in the journal Frontiers in Ethology.

Operating off a hunch, a team of scientists decided to monitor rattlesnakes’ heart rates as the animals underwent a stressful situation, with and without another snake nearby. They found snakes that faced stress alone experienced a greater spike in their heart rates than those that had company.

“Snakes and reptiles are really interesting, because I think they’re often overlooked in their behavior,” Chelsea Martin, a co-author of the study and biologist at Loma Linda University, tells CNN’s Jackie Wattles. “People are often really afraid of snakes … [but] they’re not so different from us. They have moms that take care of their children. They’re able to reduce their stress when they’re together. That’s something that we as humans do, too.”

Because snakes are solitary foragers, scientists typically consider the animals to be asocial, the study authors write. But some research has found examples of snake behaviors that appear more social, such as male snakes guarding female mates and female snakes grouping together during gestation.

The researchers wanted to study social buffering, which is when an organism’s stress is reduced in the presence of a companion. While other studies have observed social buffering in animals including fish, birds, humans, non-human primates, other mammals and even termites, it had never been reported in reptiles, according to the paper.

“I’m so pleased to see a well-conceived study that adds to our understanding of sociality in rattlesnakes,” Erika Nowak, who studies reptiles and amphibians at Northern Arizona University and did not contribute to the study, tells CNN.

To measure how snakes respond to stress, the researchers attached heart rate monitors to 25 adult southern Pacific rattlesnakes caught in the wild in Southern California. They placed each animal in a bucket—either alone, with another snake or with a rope, to see if just the presence of another object made a difference in their stress.

Then, the researchers disturbed the snakes by banging on the buckets with PVC pipes, and they measured how much the reptiles’ heart rates increased. Snakes with a companion experienced a significantly smaller spike in heart rate than the snakes in solitude or paired with a rope, suggesting that social buffering exists in this species.

“These animals aren’t all that different from us,” William Hayes, a co-author of the study and biologist at Loma Linda University, tells the Washington Post’s Kyle Melnick. “They’re sentient creatures. They have emotions; they have fear; they experience pain.”

The researchers compared the change in heart rate between female and male snakes, but they did not find a significant difference. The team also found no difference between populations of mountain-dwelling snakes that den together in the winter and lowland snakes that spend the winter alone.

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

The study might also shed light on how to care for snakes in captivity. When organisms get stressed out, they release hormones into their blood that affect their behavior, nervous system and immune system, per the paper. Chronic stress can put organisms at an increased risk of disease.

“[T]his [and other] research clearly shows that snakes could benefit from having cagemates,” Nowak tells CNN.

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