Date of Award

2023

Degree Type

Open Access Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

First Advisor

Stephen C. Richter

Abstract

To maximize energy available for foraging or reproduction, optimality theory suggests individuals allocate energy toward defensive behaviors equivalent to risk of predation. In this framework, repeat encounters with humans that do not reduce individual fitness could result in a decreased defensive response toward humans in subsequent encounters. I investigated the role individual experience played in shaping the defensive behaviors and frequency of site use of foraging of eastern copperheads (Agkistrodon contortrix) at Koomer Ridge Campground in the Daniel Boone National Forest, Kentucky. Since 2015 this site has been used for ongoing, annual mark-recapture studies of the foraging ecology of copperheads as they predate emerging annual cicadas (Neotibicen tibicen tibicen). Using a standardized behavioral trial for vipers, I tested whether copperhead defensive behavior toward humans was influenced by long-term capture history, within-season site-use history, body size, sex, and soil temperature. Model averaging results indicated that intensity of copperhead behavioral response to humans increased with number of years an individual had been recaptured, but no other explanatory variables significantly influenced behavior. The frequency at which an individual foraged at Koomer during the field season was positively, significantly related to the number of years they had been recaptured. These results indicate that copperheads with longer capture histories are coming to the site to forage more frequently and are more willing to defend their foraging opportunities. My study suggests that free-ranging copperheads are able to modulate their foraging and defensive behavior based on previous experience with humans, leading to some individuals becoming more tolerant.

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