Meeting Abstract
Respiratory evaporative heat loss generates a “cold-nose” effect in snakes, indicated by a stark difference in temperature between the rostrum and body. This phenomenon is implicated in thermal targeting in snakes that utilize infrared imaging (i.e., rattlesnakes, and by extension possibly other pit vipers, and boas and pythons). These snakes possess facial pit organs that detect the heat generated by infrared photons, and transmit this information via a unique neural pathway to the brain’s optic tectum. Once there, images of the thermal environment merge with visual images for more effective predatory and defensive targeting. Just as cooling augments the sensitivity of some artificial IR-imaging cameras, cooling of snake pit organs may enhance the quality of the image produced by lessening the effects of thermal background noise. As an initial approach to better understand the role of rostral cooling in snakes, we hypothesized that rostral cooling is more anatomically expansive in snakes possessing infrared-imaging systems than in those without IR capabilities. To test this hypothesis, we utilized infrared thermography to examine a variety of species of boid, crotaline, and colubrid snakes. We then used data generated from IR thermograms to measure and describe the extent of surface cooling relative to pit organ location, as well as the variation between species. Results show that (1) rostral cooling is common in both IR-imaging and non-IR-imaging snakes, (2) the anatomical extent of rostral cooling varies between species, (3) cooling encompasses the facial areas including the pit organs, and (4) cooling is more expansive in pythons relative to boas. This may provide enhanced thermal detection capabilities in some taxa for more effective detection and localization of homeothermic prey and potential predators.
