A population estimate of whipsnakes, Masticophis t. taeniatus, utilizing communal hibernacula at Lone Rock, Tooele County, Utah, was made by taking samples in autumn 1973 and in spring 1974. The number of whipsnakes using this site was estimated by various methods to be 425-543. Confidence limits for the Lincoln Index were 276-618. Estimates of postdispersal density ranged from 0.15-0.22 whipsnake/ha and 17.7-26 g/ha. Whipsnakes used at least three separate dens at this location, differing from other sites where only one den per den complex is used. Age structure appeared equally balanced among various age groups older than 1 year old, and the latter was underrepresented. Sex ratios were significantly biased toward ? ?. The future [...]