Dry Season Dietary Ecology of Sloth Bears (Melursus ursinus) in Chitwan National Park, Nepal : foraging strategies shaped by elevation, habitat type, and tiger presence

Sammanfattning

The sloth bear (Melursus ursinus) is a myrmecophagous species that depends heavily on termites and ants during the dry season when fruit resources decline. Studying this dietary reliance is vital for understanding how sloth bears adapt to seasonal shortages while navigating ecological pressures such as predators and human disturbance. In the Madi–Bagai sector of Chitwan National Park, Nepal—a landscape marked by habitat diversity and human–wildlife conflict—this study used scat analysis (n = 61) and habitat surveys across 291.85 km² to examine how diet varies with elevation, forest type, predator presence, and human disturbance. Termites were the dominant prey (80.3%), followed by ants (15.5%), particularly Camponotus and Pheidole. Termite occurrence increased with elevation and was highest in grasslands and riverine forests, while ant fragments declined with elevation and were most common in Sal forests. Tiger detections correlated with higher termite intake and reduced ant consumption. This suggests a predator-driven dietary shift consistent with the "landscape of fear" mechanism, where sloth bears adjust foraging to avoid predation risk. Human disturbance scores showed no significant relationship with scat density. These termite and ant use patterns reflect a flexible foraging strategy that responds to environmental gradients and predator cues. By linking diet composition to ecological variables and spatial risk, the study highlights the need to conserve diverse microhabitats, especially termite-rich zones, within human-impacted landscapes.