Demography and Home Range of the Frillneck Lizard, Chlamydosaurus kingii (Agamidae), in Northern Australia

The demography and home range of a population of frillneck lizards, Chlamydosaurus kingii, were examined from 1992 to 1994, in Kakadu National Park, Northern Territory, Australia. Lizards were studied using radiotelemetry and mark-recapture techniques. Reproduction occurred between November and April each year, coinciding with monsoonal conditions. Reproductive activity was highest in the first three months of the wet season. Females reached sexual maturity at 18 months of age. Males grew faster than females. Minimum longevity in the field was four years for females and six years for males. The population structure was constant at three sites, and the sex ratio exhibited a strong male bias. Density of frillneck lizards in Eucalyptus open forest varied from 0.13 to 0.78 hasup-1/sup. Males have larger dry-season home ranges (mean=1.96± 0.57 ha) than females (mean=0.63± 0.12 ha). No seasonal difference was evident in size of home range for either male or female lizards. No correlation was evident between snout-vent length and home range for either sex. This suggests that the home ranges of frillneck lizards were not determined by either food resources or body size but possibly related to social behavior. Arid-adapted agamids exhibit broad similarity in timing of the reproductive season, whereas factors such as growth and age at sexual maturity differ with body size and environmental conditions