Scholarly Commons

Chemosensory and temperature-based Prey Discrimination in Ball Pythons

Ball pythons (Python regius), like other snakes in the Boidae family, use heat-sensitive pit organs and odor-sensitive Jacobson’s organ (vomernasal organ) to detect prey. The discrimination sensitivity and interaction of these organs to influence prey detection and choice however have been poorly tested. We performed a series of two-choice experiments to determine ball python preference for specific odors and/or biologically-relevant thermal stimuli. We tested the following pairs of stimuli: 1) rat odor vs. water, 2) anterior vs posterior odors of a rat, 3) rat (familiar) vs rabbit (unfamiliar) odor, 4) rat vs orange peel odor, 5) odor from a large vs small rat, 6) thawed frozen rat vs live rat, 7) heat vs. rat odor, 8) heat & rat vs heat alone, 9) heat & rat vs rat odor alone. We used the number of tongue flicks (TFF) and time near the stimulus as measures of preference. We found that ball pythons significantly prefer rat odors to water controls and odors from the anterior over the posterior of a rat but showed no significant preference for odors from live vs thawed rats, small vs large rats, or rats vs. rabbits. Orange peels served as a strong repellent and inhibited attraction to rat odorants. Heat and rat odors were equally attractive to the snakes but heat and rat odor combined was much more attractive than heat alone or rat odor alone. Collectively our results indicate that pythons use heat and odor cues to a similar degree in detecting prey from a distance and they are able to discriminate not just between the presence or absence of prey, but are also likely to perceive differences in prey body orientation as well. This may be an important ability for effectively attacking and subduing prey. Pythons did not exhibit evidence of feeding neophobia, or avoidance of unfamiliar prey odors suggesting that they would quickly adapt to novel prey types.