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ABSTRACT.-We describe the diet of Crotalus lepidus klauberi (Banded Rock Rattlesnake) using samples collected in the field and from museum specimens, as well as several records from unpublished reports. Most records (approximately 91%) were from the northern Sierra Madrean Archipelago. Diet consisted of 55.4% lizards, 28.3% scolopendromorph centipedes, 13.8% mammals, 1.9% birds, and 0.6% snakes. Sceloporus spg. comprised 92.4% of lizards. Extrapolation suggests that Sceloporus jarrovii represents 82.3% of lizard records. Diet was independent of geographic distribution (mountain range) sex, source of sample (stomach vs. intestine/feces) and age class. However, predator snout-vent length differed significantly among prey types; snakes that ate birds were longest followed in turn by those that ate mammals, lizards, and centipedes. Collection date also differed significantly among prey classes; the mean date for centipede records was later than the mean date for squamate, bird, or mammal records. We found no difference in the elevation of collection sites among prey classes.
Descriptive natural history studies are essential for both the development of biological theory and conservation efforts (Dodd, 1987; Greene, 1994). Dietary studies are particularly important for understanding snake biology, because diet is a primary force in the evolution of snake morphology and behavior (Gans, 1961; Cock Buning, 1983; Greene, 1983; Mushinsky 1987; Greene, 1992, 1997; Rodriguez-Robles et al., 1999; Rodriguez-Robles and Greene, 1999). As landscapes become increasingly fragmented and climate change alters species distributions (Meffe and Carroll, 1997), a thorough knowledge of diet of affected taxa will be vital for successful conservation. Based in part on the difficulty of obtaining large sample sizes, information regarding the diet of most snake species is anecdotal (Mushinsky, 1987). Herein, we describe and evaluate variability in the diet of Crotalus lepidus klauberi (Banded Rock Rattlesnake), and discuss autecological and conservation implications. A collaborative approach, combining data from field studies with data obtained from museum specimens and historical records, permits us to progress beyond the anecdotal.
As its common name implies, Crotalus lepidus (Rock Rattlesnake) is predominantly saxicolous and found on ridges and in drainages in and and semiarid hillsides or mountains from 300-- 2930 m (Stebbins, 1985). Crotalus lepidus is distributed from southeastern Arizona, southern New Mexico and west Texas south to Jalisco, Mexico, (Stebbins, 1985). Four subspecies are recognized, C. l. klauberi, Crotalus...