Life in the Thornscrub: Movement, Home Range, and Territoriality of the Reticulate Collared Lizard

Hibbitts, Toby J. 

Texas A&M Natural Resources Institute

Biodiversity Research and Teaching Collection

Wildlife and Fisheries Sciences Department

Texas A&M University

College Station, TX

thibbitts@tamu.edu

Garrett, Timothy B. 

Biodiversity Research and Teaching Collection

Wildlife and Fisheries Sciences Department

Texas A&M University

College Station, TX

Adams, Connor S. 

Texas A&M Natural Resources Institute

College Station, TX

Campbell, Tyler A. 

East Foundation

San Antonio, TX

Walkup, Danielle K.

Johnson, Timothy E.

Ryberg, Wade A. 

Texas A&M Natural Resources Institute

College Station, TX

Over an animal’s lifetime, several habitats may be required for persistence, and the collection of movements within and among these habitats make up that animal’s home range. For lizards, variation in home range size is best explained by either sit-and-wait or active foraging styles. Entire lizard families typically share characteristic foraging styles; however, within the subfamily Crotaphytinae, foraging style characteristics do not appear to be shared. In this study, we explore movements, home range size, and territoriality of the Reticulate Collared Lizard (Crotaphytus reticulatus), a basal taxon in the genus that could help characterize the ancestral foraging style for all Crotaphytus. Using GPS telemetry data from 10 adult males and four adult females tracked during the breeding season over three years, we found male C. reticulatus moved significantly longer distances and maintained significantly larger home ranges and core areas than females. We observed no home range overlap in females and one case of overlap in males, although all females maintained home ranges overlapped by a single male home range. The one-to-one pattern of a male home range overlapping just a single female home range is consistent with male mate guarding or tracking observed in active foragers. Moreover, compared to the Common Collared Lizard (Crotaphytus collaris), a classic sit-and-wait forager, C. reticulatus moves more frequently, maintains a larger home range, is less territorial, and exhibits less sexual dimorphism. In an evolutionary context, this active foraging style and the associated movement, home range, and territoriality traits of C. reticulatus are considered a derived rather than ancestral condition within the Crotaphytinae. From a conservation perspective, this study confirms that private land stewardship across the C. reticulatus distribution in Texas has benefitted the species, and it suggests that regional conservation planning for the species will be most successful with continued engagement with private landowners