Patterns of behavior in the Texas tortoise, Gopherus berlandieri: a multivariate ordination approach

We compared the distribution of 19 categories of behavior exhibited by 47 a dult Texas tortoises (Gopherus berlandieri) over 3 years with the use of de trended correspondence analysis (DCA) and canonical correspondence analysis (CCA). DCA revealed a gradient from passive to active behavior along axis 1. Tortoises were more active in 1994 and less active in 1996. This pattern was likely due to the extremely hot and dry conditions in 1996. Year was t he most significant variable explaining variability in behavior when sex, a ge, size, year, and grazing treatment (pastures grazed versus ungrazed by c attle) were used as environmental variables in CCA. Age, size, and grazing treatment were not significant variables in CCA. Tortoises used proportiona lly more burrows, shallow surface depressions termed pallets, and cavity pa llets, and ate more cactus in 1996. More foraging and active behaviors, lik e courtship, were observed in 1994. Sex was a significant variable in expla ining behavioral variability after the effects of year were controlled for. Males tended to exhibit more active behaviors than females. Our analyses s uggested that the grazing regime used in Chaparral Wildlife Management Area did not affect the patterns of behavior exhibited by this protected tortoi se.