Activity budget of Bengal Monitor Varanus bengalensis: Effect of daytime, season, age and temperature

Abstract

The Bengal Monitor (Varanus bengalensis) is a large, ecologically flexible species and commonly found in many ecological settings including human-modified habitats. We conducted a study on the activity budget of this species employing the focal sampling method in the Chandpur district of Bangladesh. The Bengal Monitor spent the highest proportion of time in resting (33.09%) and the least proportion (3.75%) of time in anti-predatory behavior. The proportion of time spent on each activity by Bengal Monitor varied significantly between age classes and seasons except anti-predatory behavior. The highest proportion of basking activity was recorded for adult and sub-adult individuals in the dry season. Meanwhile, resting and foraging behavior was higher during the wet season. Locomotion activities were higher in sub-adults than in adult individuals. The duration of the activities did not differ significantly for daytime and season. However, an increase of air temperature significantly impacted lowering basking and rising locomotion activities among all behaviors of adult Bengal Monitor. The present findings suggest that the activities of the Bengal Monitor varied according to temporal and seasonal changes in the habitat's temperature, and age may crucially affect the allocation time for different activities.