Using Camera Traps to Study Wild Ungulate Ecology and Behavior in a Tropical Semi-Arid System

Abstract

Camera traps are under-utilized for studying ungulate demography and behavior. Reliable demographic and behavioral information on ungulates is critical for management as they are major drivers of ecosystems and form bulk of the large carnivore diets. We deployed camera traps in woodland and open forest habitats of Ranthambhore National Park during summer (n = 33) and winter (n = 31) to assess effects of season and habitat on body condition, age–sex structure, group size, activity patterns and budgets of chital and sambar. Adult chital body condition was significantly higher in winter (3.86 ± 0.01) than summer (2.66 ± 0.04), as was sambar (winter: 3.89 ± 0.01; summer: 3.67 ± 0.09). Adult sex ratios were consistently female-biased for chital (winter: 1.29 ± 0.004; summer: 1.84 ± 0.006) and sambar (winter: 1.6 ± 0.07; summer: 2.2 ± 0.25). Fawn: female ratios were lower in winter (chital: 9.36 ± 0.9, sambar: 4.65 ± 0.3) than summer (chital: 17.06 ± 2.5, sambar: 8 ± 2.1), reflecting the influence of their respective reproductive cycles. Mean group size was higher in winter (chital: 2.63 ± 0.11; sambar: 1.76 ± 0.05) than summer (chital: 2.39 ± 0.14; sambar: 1.62 ± 0.11), but differences were not significant. Both species exhibited bimodal crepuscular activity, shifting with sunrise, sunset, and insolation. Chital spent more time walking (54.6%) in summer, followed by foraging (29.5%); while in winter, foraging (43.7%) was more compared to walking (32.7%). For sambar, walking (50.4%) was more than foraging (39.2%) in summer; however, in winter foraging was increased to 43.5%, and walking decreased to 29.9%. This study highlights camera traps as a non-invasive tool to monitor ungulate populations, linking seasonal behavior, and habitat conditions, providing early warning signals of stress, and overall performance relevant for management.