Rattlesnakes use social buffering to alleviate stress

Social buffering, the phenomenon in which a creature’s stress levels decrease due to the presence of a companion, has been extensively studied in highly social animals like mammals and birds. However, a recent study has shed light on social buffering in rattlesnakes, marking the first evidence of this behavior in reptiles.

When animals experience acute or chronic stress, they produce an increased amount of hormones that can affect their nervous system, immune response, and behavior. Some animals have the ability to modulate their stress response when in the presence of a conspecific, effectively buffering the stress. This phenomenon is known as social buffering.

While snakes are often considered solitary creatures, there is growing research suggesting that they can exhibit complex social behavior. Nevertheless, the extent of social buffering in reptiles, as well as other asocial organisms and solitary foragers, remains largely unexplored. Researchers in the United States have conducted a study to investigate whether rattlesnakes in Southern California employ social buffering to alleviate acute stress.

The study revealed that when two snakes were together and exposed to a stressful situation, they were able to buffer each other’s stress response, similar to how humans support each other during challenging events. Chelsea Martin, a Ph.D. student at Loma Linda University and the lead author of the study published in Frontiers in Ethology, explained, “This attenuation of the stress response has not been previously observed in any reptile species.”

The scientists used a special testing apparatus for their measurements. Credit: Chelsea Martin

Snakes that rattle buffer

The presence of a snake companion significantly reduced the change in heart rate of stressed snakes. The researchers conducted their study using wild-caught rattlesnakes, allowing them to demonstrate that social buffering likely occurs in natural settings and can also persist in captivity.

The snakes used in the study were obtained from populations that exhibited both individual and communal overwintering habits. Surprisingly, the researchers found no discernible differences between snake populations that overwintered alone or in groups. Furthermore, there were no observed variations in social buffering between male and female snakes.

The fact that montane rattlesnakes hibernate communally suggests the existence of stronger social networks compared to lowland rattlesnakes, which typically overwinter individually. Additionally, female rattlesnakes are known to aggregate during pregnancy and remain with their newborn offspring. Taking these factors into account, the researchers determined that the propensity for social buffering was equally pronounced in both snake populations and among male and female individuals.

These findings contribute to our understanding of the social dynamics and stress management mechanisms in reptiles, highlighting the potential for social buffering in various snake species.

Snakes in a bucket

In their study, the researchers investigated social buffering in 25 wild-caught southern Pacific rattlesnakes. They conducted their experiments under three different conditions: when the snakes were alone, in the presence of a rope as an inanimate control object, and with a same-sex companion.

To assess the snakes’ acute stress levels and examine social buffering, the researchers relied on heart rate measurements as a reliable indicator. The snakes were equipped with electrodes near their hearts, and the sensors were connected to a heart rate monitor. The testing environment involved placing the snakes in a dark and enclosed bucket.

After allowing a 20-minute adjustment period, the snakes were deliberately disturbed. The research team, led by Martin, recorded the increase in the snakes’ heart rates from their baseline levels. They also noted the time it took for the snakes’ heart rates to return to normal and monitored the duration of their rattling behavior.

By analyzing these parameters, the researchers aimed to investigate the influence of social companionship on the snakes’ stress response and determine the presence of social buffering in this reptilian species.

An image boost for rattlesnakes

“Our findings not only offer valuable insights into the social behavior patterns of snakes,” stated Martin, “but they also have the potential to improve the public perception of rattlesnakes, which are often unfairly stigmatized. By showcasing their capacity for social buffering, our research may contribute to changing the negative perception surrounding these creatures.”

The researchers also acknowledged certain limitations of their study. Throughout the duration of the experiment, the snake pairs were confined to tight spaces, preventing the investigation of whether a stress-buffering response occurs when snakes are in proximity but not in direct physical contact. Additionally, the impact of familiarity between two snakes on their social buffering response remains an unknown variable that the researchers hope to explore in future studies.

Source: Frontiers

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