The Sloth Bear’s historical distribution includes a large portion of India, Bangladesh, and Sri Lanka, as well as the southern lowlands of Nepal and presumably Bhutan. Some unverified reports suggested that they once occurred in the western-most corner of present day Myanmar (Erdbrink 1953), but this was never confirmed and seems unlikely based on the mountainous habitat. Historically this species overlapped the distributions of Asiatic Black Bears (Ursus thibetanus) in northern India (Bargali et al. 2012), and with both Asiatic Black Bears and Sun Bears (Helarctos malayanus) in northeastern India (Choudhury 2011). Historical records are confusing, though, because Sloth Bears and Asiatic Black Bears look alike and were often not reliably distinguished.
At least 90% of the present Sloth Bear range occurs in India. Within India their distribution is constrained to the south by the ocean, to the northwest by deserts, and to the north and east by mountains. Although Sloth Bears were once common and even abundant throughout the Indian Peninsula (McTaggart Cowan 1972, Krishnan 1972, Brander 1982), their range has shrunk and densities reduced due to continuous habitat loss and human-caused mortalities. Although still found scattered across much of its former range, their actual distribution is now highly fragmented and confined mainly to five distinct regions, namely northern, northeastern, central, southeastern, and southwestern (Garshelis et al. 1999a, Johnsingh 2003, Yoganand et al. 2006, Sathyakumar et al. 2012).
The northern distribution region occurs largely within the state of Uttarakhand (Bargali 2012), but also includes the neighbouring states of Uttar Pradesh and the northwestern tip of Bihar. This northern region borders the southern and western areas of Nepal and includes trans-border populations. However, the northern region remains completely isolated from the other population regions in India due to large scale forest removal and agriculture and human settlements.
The northeastern region is the farthest east that this species occurs and is perhaps the least understood region in terms of Sloth Bear distribution. The bulk of the distribution appears to occur in the state of Assam (Choudhury 2011, Sathyakumar et al. 2012), though Sloth Bears are also known from Manipur, Megalaya and Arunachal Pradesh (where it is very rare). The fact that the distribution of Sloth Bears in this region overlaps with that of both Asiatic Black Bears and Sun Bears has made reports of Sloth Bear occurrence less reliable.
The central region is the largest region. The bulk of the distribution occurs in the states of Madhya Pradesh and Chattisgarh, but includes the states of Orissa, Andhra Pradesh, Maharashtra, Uttar Pradesh, Bihar, Jharkhand and West Bengal. Just south of this region, in the southern half of Andhra Pradesh, is the southeastern region, which occurs along the Eastern Ghats. It is not known whether bears move between the central and southeastern regions.
The southwestern area follows the Western Ghats and principally falls within the states of Maharashtra, Goa, Karnataka, Kerala and Tamil Nadu, where there may be a connection to the southeastern region. They have been observed up to 2,000 m elevation in the Western Ghats (A.J.T. Johnsingh, personal communication, in Garshelis et al. 1999a). They also stretch northwestward into Gujarat and Rajasthan.
In Nepal, Sloth Bears are most common within the narrow strip of lowland grassland–forest mosaic called the Terai. They also range into the lower Siwaliks (maximum elevation is unknown). The bears are mainly in protected areas in the central and western portions of the Terai. Since the mid-1980s, they were thought to have been extirpated from the Sukla Phanta Wildlife Reserve in western Nepal, an area containing the largest patch of continuous grassland in Nepal (Garshelis et al. 1999b). However, during a 2013 Tiger camera trap study in the reserve a photo of a Sloth Bear was captured. Then in 2014 Sloth Bear tracks and scat were recorded in the reserve as well (Babu Ram Lamichane, National Trust for Nature Conservation—Suklaphanta Conservation Program, pers. comm., 2015). Therefore, it appears that Sloth Bears have recolonized Sulka Phanta Wildlife Reserve, likely from adjacent Piliphit Tiger Reserve in Uttar Pradesh, India, which is known to have Sloth Bears (Sathyakumar et al. 2012); alternately, Sloth Bears persisted in such small numbers that they went undetected for several years (Johnsingh 2003). Some of the Sloth Bear populations in Nepal remain connected with the Indian northern region (Sathyakumar et al. 2012).
Sloth Bears have been extirpated from Bangladesh (Islam et al. 2013). The last documented records are from the mid-1990s (NCSIP-1 2001, Sarker 2006). Although they had been present in the southeastern, eastern and northeastern parts of the country, the forest patches in which they persisted have been largely removed (Sarker 2006).
Recent investigations suggest that if Sloth Bears occupy Bhutan, they are very rare. Garshelis et al. (1999a) mapped two populations of Sloth Bears in Bhutan, including Royal Manas National Park (RMNP) and Phipsoo Wildlife Sanctuary. Their range map was based on habitat-elevation information and purported documentation of presence. However, due to frequent confusion in distinguishing Sloth Bears from Asiatic Black Bears, it is now apparent that this range map was wrong. Sloth Bears appear to have a much narrower range in Bhutan, if at all. One camera trap photo in RMNP, taken in 2009, 2 km from the Indian border, is the only current verified record of presence (Garshelis et al. 2015). Grasslands, which are preferred habitat for Sloth Bears (Garshelis et al. 1999 a,b; Choudhury 2011) are present in both RMNP and Phipsoo Wildlife Sanctuary, and both of these protected areas are connected to protected areas in India, known to contain sloth bears. However, it is not known whether a true trans-boundary population exists anywhere along this border, or if just a few vagrant bears occasionally come across to the Bhutan side (Garshelis et al. 2015).
The Sri Lankan Sloth Bear subspecies is distributed in the north and east sides of the island and is closely tied with forest cover (Ratnayeke et al. 2007a). Sloth Bears occupy roughly 17% of the island and there is still a high connectivity between occupied areas. However, recent civil war activities largely occurred in the northern and eastern sides of the island, which are home to the largest contiguous forest patches and which historically supported healthy Sloth Bear populations. These areas have gone largely unprotected and it is still unknown how sloth bear distribution may have been affected (Ratnayeke et al. 2006, 2007a).