From fruit eaters to forest gardeners: Study reveals sloth bears’ role in seed dispersal

Jaipur: Sloth bears in Kumbhalgarh and Todgarh-Raoli wildlife sanctuaries are doing more than searching for termites and ants. A new study found that the species plays a significant role in dispersing the seeds of several plant species, aiding forest regeneration.The findings, published in the journal Biotropica, emerge from a study by Utkarsh Prajapati and Vijay Kumar Koli of Mohanlal Sukhadia University, Udaipur, and independent scientist K S Gopi Sundar. The researchers investigated whether seeds consumed by sloth bears remain viable after passing through the animals’ digestive tract and whether they can germinate and survive.To answer these questions, the team analysed sloth bear scats collected from Kumbhalgarh and Todgarh-Raoli wildlife sanctuaries and identified fruit species that formed an important part of the animals’ diet.

Germination and seedling survival experiments were then conducted using seeds recovered from bear scats and compared with seeds collected directly from fruits.A senior forest official said the results showed that seeds of several plant species remained viable after passing through sloth bears. “Germination success varied among species, but the study demonstrated that seeds could survive digestion and subsequently sprout.

Species examined included Grewia flavescens, Cassia fistula, Diospyros melanoxylon, Phoenix sylvestris, Ziziphus nummularia, Cordia myxa, Ficus religiosa and Lantana camara,” the official said.Researchers also found differences in germination timing between seeds recovered from scats and those collected directly from plants. “In the case of Ziziphus nummularia, seeds obtained from sloth bear scats germinated earlier than those collected from fruits.

Seeds of Cassia fistula and Lantana camara germinated only in the scat-derived seed group during the experiment, while Cordia myxa germinated only in the natural seed group,” the official added.The study further examined seedling survival after germination and found no significant difference between seedlings originating from scat-derived seeds and those from plant-collected seeds.According to the researchers, the findings provide evidence that sloth bears function as endozoochorous seed dispersers — animals that disperse seeds after consuming fruits and depositing them through their droppings.

Since sloth bears move across large areas while foraging, they have the potential to transport seeds away from parent plants and distribute them across the landscape.The study, however, highlighted an important caveat. “Seeds of Lantana camara, a non-native invasive shrub, germinated only in the scat-derived seed group during the experiment, indicating that sloth bears may contribute to the dispersal of invasive species alongside native plants,” the researchers noted.