ONTOGENIC VARIATION IN THE AUTECOLOGY OF THE GREATER EARLESS LIZARD COPHOSAURUS-TEXANUS

We investigated the potential for ontogenetic resource partitioning wi thin a population of the Texas earless lizard Cophosaurus texanus. Res ults from focal samples, line transects, haphazard observations, and s tomach flushes compiled in summer (July 1993) and autumn (September 19 95) revealed differences in microhabitat use and diet between adults a nd juveniles. Juveniles use rock perches more frequently than adult ma les, and consume smaller prey than adults. No ontogenetic differences in thermal ecology were observed. Diet differences between juveniles a nd adults may be attributed to the inability of juveniles to handle la rge prey items. Differences between juveniles and adults in prey size and microhabitat use suggest ontogenetic variation in foraging, predat or avoidance, and territory defense.