Demographic Differences in Behavior, Movement, and Habitat Use in the Toad-Headed Agama (Phrynocephalus versicolor) of the Gobi Desert (Dornogovi, Mongolia)

Demographic constraints can have a profound effect on behavioral ecology. Yet examinations of intraspecific variation considering both sex and age are rare. We assess age and sex-specific habitat use, movement, and behavior in variegated toad-headed agamas (Phrynocephalus versicolor) in the Gobi Desert, Mongolia. We predicted that juveniles would move and forage more than either adult sex and would engage in more random movement paths (i.e., higher entropy) than adults. We conducted 15 min focal observations, marking locations every 30 s to delineate the movement path of individuals. We recorded foraging and tail displays throughout the observation and habitat data at each marker. We found no sex-specific variation in behavior, number of moves, or entropy, but did record sex-specific variation in habitat use and movement paths. Age-specific variation in behavior, movement, entropy, and habitat use was prevalent and nuanced. Juveniles ate, dug, moved, and tail displayed more than adults, and they had movement paths with higher entropy than either adult sex. Sex and age-based variation in behavior, movement, and habitat use could arise from differential body size, experience, or reproductive status. Future work is needed to understand the function of tail displays and the relationship of entropy in movement paths to behavioral ecology.