Sex Differences in Activity and Movements in the Pig-Nosed Turtle, Carettochelys insculpta, in the Wet-Dry Tropics of Australia

Abstract
Dry season movement patterns, home ranges, and activity was studied in a population of pig-nosed turtles (Carettochelys insculpta) in the wet-dry tropics of northern Australia. Compared to other turtles inhabiting lotic habitats, C. insculpta occupied considerably larger home ranges, covering up to 10 km of river. Of previously published factors influencing home range size, low productivity of the (micro) habitat may best explain the extensive home ranges in C. insculpta. Patchiness and low nutrient value of the chief food (aquatic vegetation) of C. insculpta may force turtles to cover large expanses of river to acquire sufficient energy for growth and reproduction. Females were more active, moved farther, and occupied larger home ranges than males. Home ranges of females comprised 1–4 activity centers, many of which were associated with thermal springs. We suggest that females may exhibit increased activity and movements relative to males because of sexual inequality in parental investment, wher...