Yale researchers have made a breakthrough in understanding how pit vipers are able to detect prey in the dark using their infrared sensors. In a study published in the Proceedings of the National Academy of Sciences, physicists Isabella Graf and Benjamin Machta created a mathematical model to explain the snakes' remarkable thermosensitivity.
Pit vipers, found in a range of habitats from jungles to deserts, use their infrared sensors to detect even the smallest changes in temperature. These sensors are only as sensitive as those of humans, so the question arises: how are the snakes able to detect milli-Kelvin changes in temperature in widely varying environments?
Graf and Machta's mathematical model suggests that pit vipers have a biological mechanism that amplifies small signals and transmits them to their brain with high fidelity. The researchers discovered that there is a "bifurcation" point in the neuronal response of the snakes, where the less-sensitive temperature sensors exhibit a high degree of cooperation. Near this point, the snake's brain is able to gather almost as much information about temperature as if it could read out the measurement from each individual sensor and average them together perfectly.
"This is how a pit viper finds its dinner in the dead of night," Machta explained.
The study also accounted for the way pit vipers maintain their thermal sensitivity despite sweeping shifts in temperature between day and night. The researchers incorporated a "feedback" feature into their mathematical model, which automatically protects the overall sensitivity of the system throughout temperature swings.
Graf and Machta believe that their findings may have applications beyond the nocturnal hunting abilities of pit vipers. They suggest that similar feedback and design principles may be found in other sensory systems that need to detect tiny signals in varying environments.
The research was supported by the National Institutes of Health, a Simons Investigator award, and the German Research Foundation.
This breakthrough in understanding the sensory abilities of pit vipers sheds light on how these snakes are able to navigate and find prey in the dark. The mathematical model developed by Yale researchers Graf and Machta provides insights into the biological mechanisms that enable pit vipers to amplify small temperature signals and transmit them to their brain with high fidelity. The study also offers potential applications for other sensory systems that need to detect tiny signals in varying environments.
