Sloth bears play an important but often overlooked role in maintaining India’s dry deciduous forests by dispersing viable seeds and influencing the regeneration of vegetation, according to a study conducted in Rajasthan’s Aravalli range.
Researchers surveyed the south central Aravallis between November 2021 and July 2022 and analyzed 180 sloth bear droppings. They found that the animals significantly changed their diet according to seasonal food availability.
During winter, plant based foods were more prominent, while the bears shifted toward animal based foods in summer. Ants appeared in more than 80% of the winter samples, while termites dominated the summer samples. Among fruits, donkey berry (Grewia flavescens) was an important food source in both seasons, while Ziziphus nummularia was preferred in winter and golden shower tree (Cassia fistula) in summer.
Researchers also tested whether seeds survived the bears’ digestive process. They planted 50 seeds from each of eight important plant species half collected from bear droppings and half directly from fruits. Seeds from six species remained highly viable after passing through the bears’ digestive tracts.
In some cases, digestion actually appeared to accelerate germination. For example Ziziphus nummularia seeds from bear droppings germinated in about 50 days compared with around 100 days for seeds taken directly from fruits.
However, the study also highlights a potential downside. Sloth bears may help spread Lantana camara one of India’s invasive shrubs. Three of the 25 Lantana seeds collected from bear droppings germinated, while none of the seeds collected directly from fruits did. Because sloth bears have relatively large home ranges, researchers suggest they could potentially transport the invasive plant across considerable distances.
The findings highlight how omnivores can influence entire ecosystems beyond their role as consumers. By moving seeds across their habitats and affecting which plants regenerate, sloth bears may help shape the composition of dry forests.
Sloth bears are not merely forest inhabitants their feeding and movement patterns can actively shape vegetation and forest regeneration, although they may also unintentionally spread invasive plants such as Lantana.