Hibernation and Hibernacula Attributes Associated with Timber Rattlesnakes at Center Hill Lake in Dekalb County, Tennessee
Bryan, Danny L.
Cumberland University, Lebanon, TN USA
The Timber Rattlesnake (Crotalus horridus) is facing serious threats throughout the United States, with population studies indicating a decreasing trend throughout its range. Timber Rattlesnakes often return to a historical hibernaculum in subsequent years, and maintaining protected hibernacula is critical to their viability and survival. Identification of important habitat characteristics is needed to define optimal habitat. Critical attributes include appropriate thermal properties, insolation (solar radiation), access to spaces below frost line, and various soil properties. Natural hibernacula in this study were located on southwest-facing slopes with exposed limestone seams. Timber rattlesnakes implanted with radio-transmitters were observed hibernating between 122-175 days, with egress beginning in mid- to late March and ingress beginning in mid- late October. Plots were established at 16 hibernacula and at 20 random locations to measure percent slope, aspect, percent exposed rock, total number of trees, total basal area, and densities of tree species to determine if differences existed. All hibernacula in this study had a south to southwest exposure, and percent slope was highly variable and did not appear to be an important factor in determining hibernacula sites. To summarize, percent exposed rock, presence of an exposed limestone rock seam, total number of trees, total basal area, slope position, and aspect are contributing factors when timber rattlesnakes are selecting hibernacula sites. Total number of trees was less at hibernacula sites than at random plots, and tree species that prefer xeric conditions were more common at hibernacula.