Physiological and behavioral effects of harassment on wild western diamond-backed rattlesnakes

Cocks, Karina Yvonne (2023) Physiological and behavioral effects of harassment on wild western diamond-backed rattlesnakes. Masters thesis, Northern Arizona University.

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Abstract

Human-rattlesnake interactions are becoming more common as human development increases. Informed management of these interactions is crucial to prevent snakebite in humans while preserving rattlesnakes’ roles in their ecosystems. The objective of this study was to understand how rattlesnakes respond to the harassment followed by removal to a new area to determine whether providing a minimal stressor to the snakes will minimize human-snake interactions. This work may inform future management strategies that can decrease the frequency of human-rattlesnake interactions. I investigated the effects of a novel harassment method on the plasma corticosterone (CORT) levels in wild Western Diamond-backed Rattlesnakes (Crotalus atrox) in Arizona. I also investigated the behavioral, spatial, and physiological effects of repeated instances of the novel harassment method coupled with short distance translocation (SDT) in five telemetered adult male C. atrox at Tuzigoot National Monument. Corticosterone levels in snakes that experienced harassment were higher than baseline CORT levels. Snakes that were treated with adrenocorticotropin (ACTH), which is meant to elicit a “maximum” CORT response, did not differ in plasma CORT levels from snakes that experienced harassment. At Tuzigoot National Monument, three snakes were subjected to harassment and SDT (“treatment”), and two snakes received SDT without harassment (“control”). While sample sizes were too small to allow for statistical analyses, patterns in the data suggested that: 1) snakes that experienced harassment and SDT had smaller activity ranges than snakes that only experienced SDT; 2) there was no difference in the distance moved per day excluding treatment days between the two groups; 3) post-treatment movement (flight) distances did not differ between the two groups; 4) average 24-hour Overall Dynamic Body Acceleration (ODBA) was not affected by treatment; 5) there was no difference in body temperatures between groups; 6) there was no difference in defensive behavior between groups; and 7) there was no difference in post-harassment CORT levels between groups. My findings indicate that Western Diamond-backed Rattlesnakes responded to this novel harassment method with a high stress response. However, there was little evidence that spatial ecology, body temperatures, and behaviors changed as a result of harassment coupled with SDT. More research and additional data analyses are needed to determine if repeated instances of this harassment method coupled with SDT could lead to human avoidance and learning in rattlesnakes and if this method could be used as a management strategy to decrease the likelihood of human-rattlesnake interactions.

Item Type:	Thesis (Masters)
Publisher’s Statement:	© Copyright is held by the author. Digital access to this material is made possible by the Cline Library, Northern Arizona University. Further transmission, reproduction or presentation of protected items is prohibited except with permission of the author.
Keywords:	Western diamondbacked rattlesnakes, Human-snake interactions; Wildlife management;
Subjects:	Q Science > QL Zoology
NAU Depositing Author Academic Status:	Student
Department/Unit:	Graduate College > Theses and Dissertations College of the Environment, Forestry, and Natural Sciences > Biological Sciences
Date Deposited:	09 Jul 2026 17:44
Last Modified:	09 Jul 2026 17:44
URI:	https://openknowledge.nau.edu/id/eprint/6284

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