Prachi Thatte PhD student, National Centre for Biological Sciences, Bangalore, India
Bilaspur is an agriculture dominated district in the north western part of the state of Chhattisgarh. It is known for the aromatic Dubraj variety of rice. Nearly 65% of the land area of Bilaspur is under agriculture. What remains is covered by villages and towns, industries and fragments of forests. The forest fragments are mainly found on hillocks and around boulders. Inspite of the patchy distribution of forests, sloth bears thrive in this landscape.
Harendra Singh Bargali and co-authors carried out a study to understand more about these sloth bears living in the agriculture dominated landscape. They wanted to investigate what sloth bears ate in this fragmented landscape.
Following sloth bears to observe what they eat can be challenging and not always feasible as they are active at night. How else could they study what sloth bears ate?
Sloth bear (Melursus ursinus). Photo by David V Raju, via Wikimedia Commons
Examining fecal samples (scat) is a common technique used in research to understand feeding habits of wild animals. Remains of food found in the scat are identified using reference collections of potential food samples. For example, the feces of animals that eat fruits often contain seeds of the fruits. A reference collection of seeds is used in that case to identify what fruits the animal has eaten. For carnivores, the hair and bones in the diet are used to identify the prey species.
For this study, the researchers collected sloth bear scat samples from May 1998 to December 2000 from Pendra and Marwahi areas of the Northern Bilaspur Forest Division. Contents of 568 scats were examined with the naked eye or using a microscope, wherever necessary. Out of the total number of scats, 192 scats were collected in summer, 192 scats were collected in winter and 184 scats were collected in monsoon. Collecting scats in different seasons allowed the researchers to understand if there are any seasonal changes in sloth bear diet.
Overall, researchers found insects to be the most frequently eaten food item. Among insects, termites were found to occur more frequently than ants and bees. Researchers identified 21 species of plants from the bear scat. Most plant material in the scat consisted of fruits, except groundnuts and mahua flowers found in some. Fruits of the Banyan tree (Ficus bengalensis), were the most frequently eaten fruits by the bears, followed by fruits of the white fig tree (Ficus virens). Bears also were found to occasionally eat groundnuts and corn from the crop fields.
Bilaspur district map. By Abhijit Sathe (derivative work), via Wikimedia Commons
Researchers found some seasonal variation in the diet of sloth bears. Plant material made up most of the diet during summer. During winter and monsoon, termites and ants dominated. Other studies in central India have found similar patterns, with termites and other insects dominating the diet in monsoon and early winter and fruits dominating in late winter and summer.
Researchers suggest that the observed pattern is governed by the availability of food items. Fig species which fruit throughout the year were found to contribute to the diet in all the seasons. Number of termite mounds on the ground is generally higher in the monsoon compared to summer, thus the higher contribution of termites to bear diet. Seasonal flowering and fruiting increases the amount of plant material in sloth bear scat in summer. For example, mahua (Madhuca indica) flowers in the month of March-April. Sloth bears are known to gorge on these flowers.
Bears also frequently get into conflicts with people in the mahua season. People collect mahua flowers, to make a local alcoholic brew popular in central India, and often encounter bears during their early morning collection trips into the forest.
Sloth bears in the study area live in patches of forest surrounded by agriculture and human settlements. The authors suggest reducing human activities in the forest patches and avoiding lopping of fig trees which are an important part of the sloth bear diet. Presence of groundnut and corn in the diet suggested occasional crop raiding by sloth bears. Hence the researchers also suggest not cultivating groundnut and corn close to the sloth bear habitat patches to avoid human-bear conflict.
This study investigating diet of sloth bears was carried out as a part of a larger project aimed at studying ecology of sloth bears in the fragmented landscape of North Bilaspur- their habitat, diet and their interaction with humans. “Ours was the first study on sloth bears outside protected areas” said Bargali, the lead author of the study. Just four years after the study, the authors noticed a decline in the population of sloth bears in North Bilaspur.
“We need to shift our focus from protected areas and adopt a landscape level approach for sloth bear conservation” Bargali says. Being one of the most widely distributed species in central India, sloth bears frequently occur outside protected areas. Understanding their behavior and ecology in fragmented forests outside protected areas, like the North Bilaspur Forest Division, is hence criti cal for ensuring long-term persistence of species in the central Indian landscape.
Original Paper: Bargali, H. S., Akhtar, N. and Chauhan, N. P. S. (2004). Feeding ecology of sloth bears in a disturbed area in central India Study area. Ursus 15, 212–217.