Environmental influences on exploratory behavior in six species of southern California rattlesnakes

Armstrong, Deanni

University of California - San Bernardino

San Bernardino, California USA

Martin, Chelsea

cemartin@students.llu.edu

Hayes, William K.                                                                                                                           

Department of Earth and Biological Sciences

Loma Linda University

Loma Linda, California USA

Behavior remains a relatively understudied aspect of snake biology, especially compared to other animal groups. However, research over the past few decades has revealed that snakes exhibit greater behavioral complexity than previously assumed. One emerging area of interest is personality—defined as consistent individual differences in behavior—which remains understudied in the genus Crotalus. Understanding how environmental factors, including urbanization, influence snake behavior becomes increasingly important as human-rattlesnake interactions increase due to urban expansion. Investigating how habitat affects rattlesnake personality can offer deeper insights into behavioral variation across heterogeneous environments. In this study, we examined exploratory behavior (a prominent aspect of personality) in six species of southern California rattlesnake: Western Diamond-backed Rattlesnake (C. atrox), Sidewinder (C. cerastes), Southern Pacific Rattlesnake (C. helleri), Red Diamond Rattlesnake (C. ruber), Southwestern Speckled Rattlesnake (C. pyrrhus), and Mojave Rattlesnake (C. scutulatus). Individuals were collected from different bioregions across southern California (coast, desert, mountain, and valley) and tested in two laboratory open-field trials. We hypothesized that snakes from more developed and open habitats need to search more for resources and would be more exploratory. Preliminary analyses for four species (C. atrox, C. cerastes, C. helleri, and C. ruber) indicates the presence of personality across all species, as individuals displayed consistent behavior across trials. Exploratory behavior varied with habitat characteristics. Snakes from habitats with higher annual temperature explored less; C. ruber and C. helleri from more urbanized areas explored more; C. helleri from forested areas explored less; and C. cerastes from regions with higher precipitation explored more. Gravid females were less exploratory than males and non-gravid females, suggesting that reproductive state may also influence exploration. These findings suggest that habitat type—including urbanization—can influence rattlesnake personality. This study lays the groundwork for future research exploring how behavioral traits of rattlesnakes might be shaped by environmental change.