Odorized air current trailing by garter snakes, Thamnophis sirtalis

Area of Science:

• Ethology
• Sensory Ecology
• Chemosensation

Background:

• The red-sided garter snake (Thamnophis sirtalis parietalis) is known for its complex foraging behaviors.
• Understanding chemosensory mechanisms is vital for comprehending animal navigation and predator-prey interactions.

Purpose of the Study:

• To investigate the olfactory capabilities of adult red-sided garter snakes in response to airborne odor trails.
• To determine the role of the vomeronasal system in the snakes' ability to detect and follow chemical cues.

Main Methods:

• Utilized an airtight T-maze apparatus with controlled airflow to present olfactory stimuli.
• Tested responses to varying concentrations of earthworm extract to identify threshold detection levels.
• Investigated the effect of differentially blocking vomeronasal ducts on trailing behavior.

Main Results:

• Snakes successfully trailed earthworm extract across a range of concentrations.
• A significant increase in tongue-flick rate and speed was observed at a 10% concentration, indicating a potential threshold.
• Complete blockage of vomeronasal ducts abolished trailing behavior, while unilateral blockage induced directional bias.

Conclusions:

• The vomeronasal system is essential for airborne odor trail following in Thamnophis sirtalis parietalis.
• A positive correlation exists between tongue-flick rate and speed, suggesting integrated sensory-motor responses.
• The tongue-vomeronasal system likely functions as a chemotaxic system, guiding snakes along odor gradients.