RATTLESNAKES

PROJECT DESCRIPTION: My Master's research focused around the behavioral ecology of Timber Rattlesnakes (Crotalus horridus) during hibernation. I tested whether rattlesnakes emerged throughout winter during short-term warming events, how long they stayed on the surface, and what effect that had on their fat stores to survive hibernation. 

• HIGHLIGHTS: We found that rattlesnakes in Tennessee did in fact emerge occasionally (<10 times) throughout winter; they would stay on the surface basking for an average of 5 hrs before returning back underground. As an ectotherm, basking in the sun elevates a snake's body temperature, increasing metabolism, and therefore burning through accumulated energy stores from summer foraging.

• While basking almost doubled their energy expenditure, hibernating rattlesnakes metabolism is so reduced (~10 x lower than non-hibernating rates), that basking has little effect on their overall energy budget. For example, to replace the energy lost from basking 5 hrs a day, everyday, for 5 months (average hibernation in Tennessee), the snake would need to eat 1 extra field mouse to offset the 'cost of basking'. So why don't snakes bask more often? There are likely many factors... reduced prey availability during winter, snakes are more sluggish during cold weather and more susceptible to predation, and they need to escape lethal temperatures on the surface.

PAPER LINK: Mid-winter emergence in hibernating Timber Rattlesnakes (Crotalus horridus). Journal of Herpetology 50(2): 203–208.

PAPER LINK: Body temperatures and winter activity in overwintering Timber Rattlesnakes (Crotalus horridus) in Tennessee. Herpetological Conservation and Biology 12(3): 601–615.