Introduction
Bangladesh has two extant species of bears: the Tibetan black bear Ursus thibetanus thibetanus (a subspecies of the Asiatic black bear Ursus thibetanus) and the Malayan sun bear Helarctos malayanus malayanus (a subspecies of the sun bear Helarctos malayanus; Alam, Reference Alam2015a; Naher, Reference Naher2015). In the most recent regional assessment of the IUCN, the sloth bear Melursus ursinus was assessed as locally extirpated in Bangladesh, which has been linked to the disappearance of the wet deciduous forests of northern and central Bangladesh that were rich in termite mounds and formed the primary habitat of this myrmecophagous species in the country (Alam, Reference Alam2015b). The shal Shorea robusta-dominated wet deciduous forests that once sprawled across the northern and central floodplains of Bangladesh have been decimated over the last 5 decades through deforestation, illegal encroachment and felling of primary stands. The remnant patches, consisting mostly of secondary growths, are now the most degraded and fragmented forest type in the country (Khan, Reference Khan2018). Furthermore, across the international border in India, the sloth bear does not occur in Tripura and Mizoram, and its presence is uncertain in Meghalaya (Dharaiya et al., Reference Dharaiya, Bargali and Sharp2020; Garshelis et al., Reference Garshelis, Dharaiya, Sharp and Pigeon2022a). This localized extinction of sloth bears was predicted in various studies (Garshelis et al., Reference Garshelis, Joshi and Smith1999; Ahmed et al., Reference Ahmed, Kabir, Ahmed, Ahmed, Begum, Hassan and Khondker2009; Islam et al., Reference Islam, Uddin, Aziz, Muzaffar, Chakma and Chowdhury2013).
The Asiatic black bear and the sun bear are categorized as Vulnerable globally (Scotson et al., Reference Scotson, Fredriksson, Augeri, Cheah, Ngoprasert and Wai-Ming2017; Garshelis & Steinmetz, Reference Garshelis and Steinmetz2020) and as Critically Endangered in Bangladesh (Naher, Reference Naher2015; Alam, Reference Alam2015a). The riparian, hilly, mixed evergreen forests of eastern Bangladesh are their last refuges in the country (Fig. 1a,b; Islam et al., Reference Islam, Uddin, Aziz, Muzaffar, Chakma and Chowdhury2013; Alam, Reference Alam2015a; Naher, Reference Naher2015; Khan, Reference Khan2018). Despite the threats such as habitat loss and the conflict that the bears are facing in Bangladesh, there has been a lack of pertinent research and conservation investment. To our knowledge (Akash & Zakir, Reference Akash and Zakir2020), there is only one peer-reviewed study (Islam et al., Reference Islam, Uddin, Aziz, Muzaffar, Chakma and Chowdhury2013) that has assessed the status of bears in Bangladesh. That study was the outcome of a project (Islam et al., Reference Islam, Muzaffar, Aziz, Kabir, Uddin and Chakma2010) that investigated the status of bears in Bangladesh during 2008–2010 using semi-structured interviews and sign survey methods. Islam et al. (Reference Islam, Uddin, Aziz, Muzaffar, Chakma and Chowdhury2013) remarked that black bears were ‘scattered’ and ‘likely to be very low in number’. Because of the lack of verifiable evidence of sun bears, this species was reported as ‘vagrant’ and moving into trans-border forests from India.
Fig. 1 Distribution range and evidence of bears in Bangladesh: (a) Tibetan black bear Ursus thibetanus thibetanus, (b) Malayan sun bear Helarctos malayanus malayanus. Distribution maps for both the Indian subcontinent and Bangladesh were adapted from Scotson et al. (Reference Scotson, Fredriksson, Augeri, Cheah, Ngoprasert and Wai-Ming2017) and Garshelis & Steinmetz (Reference Garshelis and Steinmetz2020), respectively. Bear records were compiled from Islam et al. (Reference Islam, Uddin, Aziz, Muzaffar, Chakma and Chowdhury2013), Sarkar (Reference Sarker2016), Chakma (Reference Chakma2016), Creative Conservation Alliance (2016) and this study. Conflict incidents were compiled from media reports (Table 1).
As it has been more than a decade since this first country-wide survey, the distribution and conservation status of bears in Bangladesh warrants an update. There has been a steady increase in media reports of human–bear conflicts in recent years, which Islam et al. (Reference Islam, Uddin, Aziz, Muzaffar, Chakma and Chowdhury2013) reported to be an uncommon issue. Garshelis et al. (Reference Garshelis, Dharaiya, Sharp and Pigeon2022a) reported the Asiatic black bear to be ‘fairly widespread’ in Bangladesh, in contrast to the findings of Islam et al. (Reference Islam, Uddin, Aziz, Muzaffar, Chakma and Chowdhury2013). There have been several recent camera-trap records of sun bears from south-eastern Bangladesh (e.g. Creative Conservation Alliance, 2016). In addition, Sarker (Reference Sarker2016) highlighted multiple sun bear localities in the country.
The absence of adequate and focused research investment on the least-known carnivores (Akash & Zakir, Reference Akash and Zakir2020; Srivathsa et al., Reference Srivathsa, Banerjee, Banerjee, Chawla and Das2022) and the inconsistencies between various sources concerning the distribution of bears in Bangladesh highlight the need to systematically reassess the conservation status and distribution of bears in the country.
In this study, we compiled verifiable accounts of bears in Bangladesh from peer-reviewed studies and grey literature produced by local conservation organizations. We provide evidence of a small population of the Asiatic black bear from a camera-trap survey carried out during March–July 2022 in north-eastern Bangladesh. We also compare verifiable reports of human–bear conflicts in Bangladesh from various sources to findings of previously published studies.
Study area
The mixed evergreen forests of eastern Bangladesh, together with the forests of southern Assam, Tripura and Mizoram states of India, form the south-western boundary of the Indo-Burma Biodiversity Hotspot (Myers et al., Reference Myers, Mittermeier, Mittermeier, Da Fonseca and Kent2000). In the north, the transboundary forests of Bangladesh constitute the northern fringes of the anticlinal Baramura-Atharamura-Longtharai-Jampui Hills (Akash et al., Reference Akash, Trageser, Zakir, Rahman, Mila and Ghose2021b). After traversing Tripura, these low-lying hill ranges re-emerge in Bangladesh and gain elevation in the Chattogram Hill Tracts (Figs 2 & 3). Southwards, the Hill Tracts become contiguous with the Rakhine Yoma mountain range, Myanmar; to the east, they cross the border, merging with the Dampa Tiger Reserve in Mizoram, India (Akash et al., Reference Akash, Trageser, Zakir, Rahman, Mila and Ghose2021b).
Fig. 2 Verifiable evidence of the Asiatic black bear in north-east Bangladesh: (a) Habiganj and Moulvibazar, two north-eastern districts, and (b) Rajkandi Reserve Forest. Circles denote the locations extracted from the literature; squares denote the camera-trap locations of this study. Land-cover features were adapted from Donlon et al. (Reference Donlon, Berruti, Buongiorno, Ferreira, Féménias and Frerick2012; Supplementary Table 1). (Readers of the printed journal are referred to the online article for a colour version of this figure.)
Fig. 3 Verifiable evidence of the Asiatic black bear and the sun bear in south-east Bangladesh. (a) Records extracted from the literature overlayed on the land-cover features of south-eastern districts, and (b) human–bear conflict incidents and camera-trap records overlayed on the land-cover features of south-eastern districts, also showing 2000–2019 forest-cover loss and patch effects near the Myanmar border. Data on land-cover features and loss of forest cover were adapted from previous studies (Donlon et al., Reference Donlon, Berruti, Buongiorno, Ferreira, Féménias and Frerick2012; Hansen et al., Reference Hansen, Potapov, Moore, Hancher, Turubanova and Tyukavina2013; Supplementary Table 1). (Readers of the printed journal are referred to the online article for a colour version of this figure.)
Of the c. 5,000 km2 of forested landscape in eastern Bangladesh, c. 500 km2 are located in north-eastern Bangladesh (Khan, Reference Khan2018; Rahman et al., Reference Rahman, McCarthy, McCarthy and Faisal2021). These landscapes are largely classified as reserve forests, set aside for the sustainable use of forestry resources (Chakma, Reference Chakma2016). North-eastern Bangladesh has six separate reserve forests (maximum altitude: 335 m), each of which is a combination of plantation forests and secondary natural mixed evergreen succession, characterized by seasonal and perennial streams and interspersed with tea plantations and villages (Zakir et al., Reference Zakir, Debbarma and Akash2020). The south-eastern reserve forests are primary dipterocarp-dominated forest patches on undulating topography (maximum altitude: 1,055 m), characterized by boulder-strewn stream networks (Chakma, Reference Chakma2016; Akash et al., Reference Akash, Trageser, Zakir, Rahman, Mila and Ghose2021b). Approximately 9.2% of these reserve forests is categorized as IUCN-designated protected area (IUCN category II national park/category IV wildlife sanctuary) to conserve and protect wildlife (Khan et al., Reference Khan, Haque, Khan, Ahmed, Chakma and Naher2022).
We carried out a camera-trap survey in the 62 km2 Rajkandi Reserve Forest, which is one of the six north-eastern reserve forests of Bangladesh (Fig. 2). Vegetation in this reserve forest comprises mosaics of thick bamboo patches, primary forests (dominated by Artocarpus spp., Ficus spp., Holigarna caustica and Tetrameles nudiflora) and plantations (dominated by Acacia spp., Albizia spp., Tectona grandis and indigenous medicinal and fruiting plants). To the south and east, this reserve forest shares a border with India; it is heavily riparian, rugged (altitude: 80–245 m) and boulder-strewn. To the north and west, it is bordered by villages and betel-leaf Piper betle plantations (Rahman et al., Reference Rahman, McCarthy, McCarthy and Faisal2021).
Methods
Camera-trap survey
We carried out a non-baited camera-trap survey to assess the diversity of terrestrial medium and large mammals for 5 months (March–July 2022) in Rajkandi Reserve Forest as part of a larger project studying the mammalian carnivores of eastern Bangladesh. We followed a grid-based approach (1 × 1 km) and deployed one camera trap within each of 13 grid cells. Before the deployment of the camera traps we conducted a reconnaissance survey traversing 65 km of transects and attempted to map the major animal trails within the Reserve Forest. We also noted geocoordinates of trees that were marked by bears. We identified c. 20 trees of two species, H. caustica and Artocarpus chama, with both old and fresh claw marks of bears. Claw-width measurements of young Asiatic black bears are indistinguishable from those of sun bears (Steinmetz & Garshelis, Reference Steinmetz and Garshelis2008; Garshelis et al., Reference Garshelis, Dharaiya, Sharp and Pigeon2022a). Claw-rake marks can also vary significantly depending on the climbing postures of the bears. Thus, we relied on other methods such as camera traps to confirm species presence. We based the selection of cells and locations of the camera traps on these field observations.
We deployed camera traps close to forest streams, cliffs and wildlife trails at a height of 25–100 cm above the ground. The mean distance between camera traps was 2 km. If deployment was at > 45 cm height, we directed the angle of view of the camera trap down at c. 20–40° relative to its vertical axis. We programmed each camera-trap unit to capture 3–5 photographs per trigger, with a capture delay period of 1–3 s between consecutive triggers. We organized the camera-trapping data following Niedballa et al. (Reference Niedballa, Sollmann, Courtiol and Wilting2016) and considered capture events to be independent if at least 30 min had elapsed between two consecutive photographs of the same species at the same station (Meek et al., Reference Meek, Ballard, Claridge, Kays and Moseby2014).
We identified animal species following Menon (Reference Menon2014) and Hunter & Barrett (Reference Hunter and Barrett2018). Asiatic black bears have a longer muzzle, bigger, visible and round pinnae and a shaggier coat, whereas sun bears have a short and blunt muzzle, smaller pinnae that give an almost earless appearance in camera-trap photos and a shorter, velvety coat. Whenever visible on camera-trap photos, we also noted the shape of chest marks: Asiatic black bears have a cream-coloured V-shaped mark, whereas sun bears have orange- or yellow-coloured marks of variable shape, or sometimes no marks at all. We shared the camera-trap photos with experts of the IUCN Species Survival Commission Bear Specialist Group for further verification of the species.
Human–bear conflict incidents
We searched online databases of Bangla and English newspapers, web-based news portals and social media sites for reports of human–bear conflict incidents. In addition, we identified relevant grey literature (e.g. project reports and book chapters) using Google Scholar (Google, Reference Google2022) and reviewed wildlife guidebooks of Bangladesh (Khan, Reference Khan2015, Reference Khan2018).
To construct our search string, we followed the guidelines of Pullin & Stewart (Reference Pullin and Stewart2006) and the methods used by Akash et al. (Reference Akash, Dheer, Dloniak and Jacobson2021a,Reference Akash, Trageser, Zakir, Rahman, Mila and Ghoseb). We included the common name of the species (‘bear’ OR ‘Malayan sun bear’ OR ‘Asiatic black bear’) AND country name (‘Bangladesh’) AND relevant keywords (‘bear attack’ OR ‘bear rescue’ OR ‘mauled by bear’) AND the name of regions where bears were reported to be present (‘Bandarban’ OR ‘Rangamati’ OR ‘Khagrachhari’ OR ‘Cox's Bazar’ OR ‘Chittagong’ OR ‘Moulvibazar’ OR ‘Habiganj’ OR ‘Sherpur’). To extract data from Bangla media reports, we used this search string in the Bangla language.
We considered a media report as valid only if it included a verifiable image (i.e. a bear dead or alive, tree marked by bears, human casualty with typical signs of being mauled by a bear), was accompanied by a detailed report and/or expert opinion, and if the reported location was within the geopolitical boundary of Bangladesh.
Categorization of data
We categorized these refined data according to spatial (up to district and subdistrict, the first- and the second-order administrative units of Bangladesh, respectively) and temporal (year, month, season) characteristics. We noted the type of incident (i.e. ‘conflict’ involving a confrontation between a human and bear or ‘poaching’ including occasions of bear hide confiscation and/or rescues of bear cubs from traffickers). We noted the number of human casualties (deaths and/or injuries), the number of bears involved (death, escape or rescue) and the causes or activities stated in the news reports as leading to these incidents. We did not classify the incidents to the species level unless there was verifiable evidence such as photographic records or DNA analysis.
We grouped the data obtained from the literature into non-verifiable (based on local information or interviews) and verifiable records (construed from camera-trap data or signs such as claw-marked trees, latrines or trophies). We extracted the geocoordinates of the sites described in Islam et al. (Reference Islam, Uddin, Aziz, Muzaffar, Chakma and Chowdhury2013). We ascertained the geocoordinates for several data points provided by Islam et al. (Reference Islam, Muzaffar, Aziz, Kabir, Uddin and Chakma2010) but determined that these were outside the international border of Bangladesh. No geocoordinates were provided in the observations of Chakma (Reference Chakma2016), Sarkar (Reference Sarker2016) and Creative Conservation Alliance (2016); in these cases we assigned the observations to the relevant subdistrict and district as described in the pertinent literature.
Preparation of maps
We plotted the data using ArcGIS 10.5 (WGS 1984 geo-datum; Esri, USA). We followed the regional classification scheme of Khan (Reference Khan2018) for discussing bear presence in north-eastern and south-eastern Bangladesh (Figs 2 & 3). We used the range map for both bear species of Scotson et al. (Reference Scotson, Fredriksson, Augeri, Cheah, Ngoprasert and Wai-Ming2017) and Garshelis & Steinmetz (Reference Garshelis and Steinmetz2020). We extracted land-cover data for eastern Bangladesh from the Sentinel-3 Sea and Land Surface Temperature Radiometer (SLSRT) level 2 dataset (Donlon et al., Reference Donlon, Berruti, Buongiorno, Ferreira, Féménias and Frerick2012) following the instructions of Polehampton et al. (Reference Polehampton, Cox, Smith, Ghent, Wooster and Xu2021), and we then reclassified the data into seven land-cover categories: floodplain, grassland–cropland mosaic, secondary forest, old growth forest, mangrove, urban area and waterbody (Supplementary Table 1). We used the Global Forest Change 2000–2019 v. 1.7 dataset (Hansen et al., Reference Hansen, Potapov, Moore, Hancher, Turubanova and Tyukavina2013) to calculate forest-cover loss in eastern Bangladesh. We adapted the elevation gradient and the distribution of waterbodies in eastern Bangladesh from the Shuttle Radar Topography Mission (SRTM) dataset (Farr & Kobrick, Reference Farr and Kobrick2000) and the Global Wetland v. 3 dataset (Gumbricht et al., Reference Gumbricht, Roman-Cuesta, Verchot, Herold, Wittmann and Householder2017).
Results
Records from the literature
Asiatic black bear
From four studies (Islam et al., Reference Islam, Muzaffar, Aziz, Kabir, Uddin and Chakma2010, Reference Islam, Uddin, Aziz, Muzaffar, Chakma and Chowdhury2013; Chakma, Reference Chakma2016; Creative Conservation Alliance, 2016) we extracted 101 sites as being in eastern Bangladesh (Figs 1a, 2a & 3a). Of these, the Asiatic black bear was reported to be present in 88 sites, 59 of which are in south-eastern Bangladesh, 26 in north-eastern Bangladesh and three in northern Bangladesh (Figs 1a, 2a & 3a; Supplementary Table 2). However, verifiable evidence was available for only 43 of these sites (20 in south-eastern Bangladesh and 23 in north-eastern Bangladesh; Figs 2a & 3a; Supplementary Table 2). Chakma (Reference Chakma2016) and Creative Conservation Alliance (2016) provided the first camera-trap evidence of Asiatic black bears in Bangladesh (Fig. 3b), with records from Kassalong Reserve Forest (northern section of south-eastern Bangladesh) and Sangu-Matamuhuri Reserve Forest (southern section of south-eastern Bangladesh; Fig. 3b). Islam et al. (Reference Islam, Uddin, Aziz, Muzaffar, Chakma and Chowdhury2013) was the only study that provided information on Asiatic black bears in the north-eastern part of Bangladesh.
Sun bear
We found 11 potential sites reported by previous studies. The records provided by Islam et al. (Reference Islam, Uddin, Aziz, Muzaffar, Chakma and Chowdhury2013) and Sarkar (Reference Sarker2016) were, however, non-verifiable. Sarkar (Reference Sarker2016) noted that Malayan sun bears had been reported in eight sites (without giving details of these observations) in the region (Fig. 3a) since 1970. The study by Creative Conservation Alliance (2016) provided the first camera-trap evidence of this species in Bangladesh, which was recorded in Sangu-Matamuhuri Reserve Forest (Fig. 3b). During a study conducted by IUCN Bangladesh, a Malayan sun bear was camera-trapped in Kassalong Reserve Forest (Fig. 3b; Haque, Reference Haque2021). Islam et al. (Reference Islam, Uddin, Aziz, Muzaffar, Chakma and Chowdhury2013) mentioned a captive Malayan sun bear in south-eastern Bangladesh but did not provide any further details. We found no verifiable evidence of the occurrence of Malayan sun bears in north-eastern Bangladesh.
Results from the 2022 camera-trap survey
We obtained 45 photographs of the Tibetan black bear in four independent events from three out of 13 deployed camera traps (totalling 988 camera-trap nights; Fig. 2b; Plate 1). All but one (Plate 1d) of these captures indicated nocturnal/crepuscular activity of the bears. In addition to the black bears, the survey recorded 13 other mammal species, including eight carnivores (two felids, three viverrids and three mustelids), three ungulates (red serow Capricornis rubidus, wild boar Sus scrofa and barking deer Muntiacus muntjak) and two primates (rhesus macaque Macaca mulatta and northern pig-tailed macaque Macaca leonina). Among the sympatric carnivores, the Asiatic golden cat Catopuma temminckii was the second largest (by body mass) after the black bear.
Plate 1 Photographs of the Tibetan black bear Ursus thibetanus thibetanus obtained during the 2022 camera-trap survey in Rajkandi Reserve Forest, north-eastern Bangladesh. Images (a–f) show representative photographs from each capture event of the species.
We identified four different individuals in the four independent capture events. We identified two black bears based on their different chest marks (Plate 1a,b). Both of them crossed the same camera-trap station travelling in the same direction on 18 May 2022 within 1 h of each other (03.10–04.11). One of these bears (Plate 1b) had an old scar above the left eye.
From the camera-trap photos taken on 24 June 2022 we noted two black bears visiting a station together, feeding on fruits of A. chama. The photographs were captured within 1 min of each other (19.26–19.27). We inferred that these were distinct individuals based on the difference in body size and snout (Plate 1e,f). Another capture of an adult black bear occurred at this station at 04.35 on 10 June 2022 (Plate 1d), and a smaller individual was recorded at a different camera-trap station at 05.58 on 14 May 2022 (Plate 1c). Although these may have been the same two individuals that were photographed on 24 June 2022, we were unable to confirm this.
Conflict incidents
From media reports published during 2003–2023 we collated 29 human–bear conflict incidents in Bangladesh (Table 1; Supplementary Table 3). All but two records (one in 2003 and another in 2005) were from 2014 onward, of which 23 took place in the last 6 years (2018–2023). These incidents resulted in 83 human casualties (80 injured, three dead) and 13 bear casualties (six dead, seven rescued). Notably, 58 human casualties occurred in just two incidents (Table 1). In both of these cases, a single Asiatic black bear strayed into human settlements, causing panic amongst the local inhabitants and leading to their retaliation against the bear. Poor management of the situation contributed to the high casualties; in addition, one Asiatic black bear was beaten to death (in Sherpur district; Table 1).
Table 1 Characteristics of human–bear conflict incidents in Bangladesh collated from 2003–2023 media reports. In the incidents marked with an asterisk (*), the bear species involved was reported to be the Asiatic black bear Ursus thibetanus; in all other cases the bear species was not reported.
Details of the conflict incidents are provided in Table 1 and Supplementary Table 3. The districts of Moulvibazar (north-eastern Bangladesh), Khagrachari, Bandarban and Rangamati (south-eastern Bangladesh) accounted for 24 incidents. In south-eastern Bangladesh most of the incidents were clustered in Rangamati (Baghaihat subdistrict) and Bandarban (Ruma subdistrict) districts (Fig. 3b; Table 1).
Different forms of incursion into forested habitats were reported as the predominant activities leading to these negative interactions, but there was no livestock depredation. Most commonly, people encountered a bear whilst working in swidden cultivation (an agrarian practice in the hilly region requiring slash-and-burn techniques), followed by interactions occurring during logging activities. Most incidents (60%) occurred in the summer (February–May).
There were reports of seven poaching incidents. In 2016 a bear skin was confiscated in Dhaka, the capital of Bangladesh; this was the only known incident of illicit trade in bear derivatives to be reported in the media (Table 1; Supplementary Table 3).
We noted a Malayan sun bear in captivity in a small menagerie in Jessore, south-western Bangladesh (Supplementary Plate 1). We also found at least two incidents involving the confiscations of three captive Asiatic black bears from unauthorized menageries by the Bangladesh Forest Department (Supplementary Plates 2 & 3). Seven cubs were rescued from south-eastern Bangladesh. In May 2022 two Asiatic black bear cubs were rescued at the India–Bangladesh border whilst being smuggled from south-eastern Bangladesh into India (Supplementary Plate 4; Mukherjee, Reference Mukherjee2022). In January 2023 two newborn bear cubs were rescued from a highway whilst being smuggled out of Bangladesh (Table 1; Supplementary Plate 5).
We found no evidence of sloth bears in Bangladesh.
Discussion
Presence of bears in Bangladesh
Our compilation of bear records, comprising 43 verifiable records from previous studies, 23 conflict incidents reported during 2018–2023 and the results from our camera-trap survey, shows that two species of bears still occur in Bangladesh. The findings can be substantiated by multiple factors. Firstly, the records were far from the international borders between Bangladesh and north-eastern Indian states (Fig. 3a). Secondly, we observed an increasing frequency of media reports on human–bear conflicts in south-eastern Bangladesh (Table 1). Furthermore, there were multiple reports of the hunting and trafficking of bears and bear cubs (Table 1; Creative Conservation Alliance, 2016). We found no evidence of sloth bears, corroborating the findings of previous studies (Garshelis et al., Reference Garshelis, Joshi and Smith1999; Ahmed et al., Reference Ahmed, Kabir, Ahmed, Ahmed, Begum, Hassan and Khondker2009; Islam et al., Reference Islam, Uddin, Aziz, Muzaffar, Chakma and Chowdhury2013).
Islam et al. (Reference Islam, Uddin, Aziz, Muzaffar, Chakma and Chowdhury2013) considered the Malayan sun bear as a transient vagrant from the forests of north-eastern India bordering Bangladesh. However, the camera-trap images obtained in Kassalong Reserve Forest (by IUCN Bangladesh) and Sangu-Matamuhuri Reserve Forest (by Creative Conservation Alliance) indicate that the species could be a resident (Fig. 3b). Both locations are comparatively rugged and continuous with the forests of Mizoram state (India) and Chin state (Myanmar), which also harbour populations of the species (Gouda et al., Reference Gouda, Chauhan, Sethy and Sahu2020). Creative Conservation Alliance (2016) also provided multiple photographs showing sun bears hunted by Indigenous People, all from Sangu-Matamuhuri Reserve Forest. These observations require further investigation into whether Malayan sun bears are indeed vagrant or have resident, edge-of-range populations in the country.
In addition, the survey sites of Islam et al. (Reference Islam, Muzaffar, Aziz, Kabir, Uddin and Chakma2010, Reference Islam, Uddin, Aziz, Muzaffar, Chakma and Chowdhury2013) form a cluster in north-eastern Bangladesh (all within 10–20 km2) and are scattered over a wide range of south-eastern Bangladesh (Figs 2a & 3a). These sites were surveyed based on local Indigenous knowledge. In places where bear populations occur in low density, signs, local knowledge and expert opinion are beneficial (Proctor et al., Reference Proctor, Garshelis, Thatte, Steinmetz, Crudge and McLellan2022); however, these approaches can lead to biased results as local knowledge is difficult to verify without empirical evidence and may sometimes be based on conjecture (Garshelis et al., Reference Garshelis, Dharaiya, Sharp and Pigeon2022a,Reference Garshelis, Pigeon, Hwang, Proctor, McShea, Fuller and Morinb).
Because of the lack of any habitat suitability modelling, and also considering the omnivorous nature of Asiatic black bears and their ability to survive in degraded forest patches (Sathyakumar et al., Reference Sathyakumar, Sharma and Charoo2013), it is difficult to infer the extent to which the forests of eastern Bangladesh are suitable for bears. Remote camera trapping and/or DNA-based sampling are now considered to be the most reliable methods for assessing and monitoring bear distributions (Proctor et al., Reference Proctor, Garshelis, Thatte, Steinmetz, Crudge and McLellan2022). These methods can help determine population status and assess threats at a national level, which are often based on expert opinion because empirical evidence is lacking. For example, Alam (Reference Alam2015a) stated that the Asiatic black bear had disappeared from north-eastern Bangladesh, whereas our findings suggest the possible presence of a small population in this region.
Human–bear conflict
Eastern Bangladesh appears to be an area of frequent human–bear conflict, based on our analysis of media reports. During 2007–2010, 47 bears were reportedly killed in this region (Islam et al., Reference Islam, Uddin, Aziz, Muzaffar, Chakma and Chowdhury2013). The reported incidents mostly took place in summer, the harvesting season of fruits and crops (Fig. 3b; Table 1). However, we are also cognizant that drawing inferences from media reports has limitations. Incidents could be under-reported, leading to underestimation of the problem, whereas over-reporting may occur because of the popularity of such stories on social media and in news outlets, or because of increased human–wildlife contact as a result of human activities encroaching into forests. It has been reported that in Dachigam National Park, Kashmir, bear attacks on people intensify in winter, but the highest intensity of crop damage occurs in summer (Charoo et al., Reference Charoo, Sharma and Sathyakumar2011). In Bhutan, incidents with bears have been reported in summer and autumn (Jamtsho & Wangchuk, Reference Jamtsho and Wangchuk2016). Human–bear conflict intensity in northern Pakistan also reached its peak in summer (Khattak et al., Reference Khattak, Mehmood, Teng, Ahmad, Rehman and Liu2022). However, one study noted that bear poaching incidents were most intense in winter in Siran and Kagan valleys, Pakistan (Ullah et al., Reference Ullah, Ullah, Ullah, Mahmood and Iqbal2020). The concentration of conflict incidents in summer suggests a possible correlation between the fruiting season and the activities of bears in these regions.
The increasing frequency of reported human–bear conflict in recent times probably indicates the presence of a larger, hitherto undocumented, edge-of-range population of the Asiatic black bear in eastern Bangladesh. The number of conflict incidents during 2018–2023 (n = 23) in Bangladesh was higher than in Bhutan and Pakistan. Jamtsho & Wangchuk (Reference Jamtsho and Wangchuk2016) noted an increase in human–bear conflict in Bhutan, totalling 19 incidents during 2013–2015. Similarly, Khattak et al. (Reference Khattak, Mehmood, Teng, Ahmad, Rehman and Liu2022) reported 14 cases within 2 years in northern Pakistan. Although Islam et al. (Reference Islam, Uddin, Aziz, Muzaffar, Chakma and Chowdhury2013) did not elaborate on the underlying drivers and causes of this conflict, they noted that 47 bears were killed during 2007–2010 in Bangladesh. Together with the tiger Panthera tigris, the Asiatic black bear and sun bear are the only carnivore species for which, in the Bangladesh Wildlife (Security and Protection) Act 2012, under Clause 52, a compensation policy has been legislated should such conflict occur. However, there have been no studies or initiatives to systematically address the patterns and drivers of human–bear conflict incidents, although such activities have been conducted for conflicts involving tigers in the Sundarbans (Akash & Zakir, Reference Akash and Zakir2020).
Illegal trade of bears
This study emphasizes the hitherto unnoticed wildlife trade and poaching activities that target bears. This is a threat as demand for live bears (for use in menageries and circuses), bear trophies and bear derivatives (bear bile, claws, etc.) is high (Sarkar, Reference Sarker2016; Kabir, Reference Kabir2019). Both bear species are protected under Schedule I of the Bangladesh Wildlife (Security and Protection) Act 2012, however, Asiatic black bears are kept in various private and government zoos across the country, with the origin of these bears remaining undocumented.
Bear conservation in eastern Bangladesh
South of 25°N, Bangladesh forms the westernmost edge of the ranges of both Asiatic black bears and Malayan sun bears. Eastern Bangladesh, combined with Tripura and southern Assam in India, forms the western tip of the Indo-Burma Biodiversity Hotspot, an ecologically uncharted area that is exceptionally rich in carnivore diversity (Khan, Reference Khan2018; Akash & Zakir, Reference Akash and Zakir2020; Akash et al., Reference Akash, Trageser, Zakir, Rahman, Mila and Ghose2021b; Zakir et al., Reference Zakir, Debbarma, Mahjabin, Debbarma and Khan2021). The region is reportedly home to all 27 Carnivora species known to be present in the country, which is nearly half of those occurring across the entire Indian subcontinent, including the leopard Panthera pardus, dhole Cuon alpinus, Asiatic golden cat, clouded leopard Neofelis nebulosa, marbled cat Pardofelis marmorata and binturong Arctictis binturong, amongst others (Chakma, Reference Chakma2016; Creative Conservation Alliance, 2016; Khan, Reference Khan2018). The rugged, riparian, mixed evergreen forests of eastern Bangladesh are also the edge-of-range habitats for Asiatic elephants Elephas maximus and rare forest ungulates such as gaur Bos gaurus and red serow (Creative Conservation Alliance, 2016).
Despite being more at risk of extinction than core populations, edge populations are especially valuable for their adaptability to marginal habitats, their genetic diversity and their ability to colonize new habitats and respond to abrupt environmental and climatic shifts (Hunter & Hutchinson, Reference Hunter and Hutchinson1994). Edge populations have the evolutionary potential for future speciation events (Lesica & Allendorf, Reference Lesica and Allendorf1995; Razgour et al., Reference Razgour, Juste, Ibáñez, Kiefer, Rebelo and Puechmaille2013).
Bear conservation efforts in Bangladesh are far below the investments made to preserve the tiger in the Sundarbans, another large carnivore (Akash & Zakir, Reference Akash and Zakir2020). Bear research in the country suffers from a lack of research infrastructure and collaboration, inadequate funding and awareness-raising programmes, logistical difficulties and a lack of knowledge regarding the conservation of less charismatic wildlife amongst policymakers (Akash & Zakir, Reference Akash and Zakir2020). To address these shortcomings, it is important that the Bangladesh government involves members of the IUCN Species Survival Commission Bear Specialist Group in Bangladesh and the Asian Bear Monitoring Expert Team in future monitoring efforts. We also recommend involving young students in bear research and expanding Bear Specialist Group membership in Bangladesh by inviting a new generation of bear biologists.
The forests of eastern Bangladesh are often selected as substitute locations for plantations and development. Although there are protection schemes in place, only c. 10% of these forests are categorized as protected areas according to globally recognized standards, such as those defined by the IUCN protected area categories (Khan et al., Reference Khan, Haque, Khan, Ahmed, Chakma and Naher2022). It also appears that > 95% of the forested landscape in the country is yet to be systematically assessed for bears (Figs 2a & 3a). Our study shows that Sangu-Matamuhuri Reserve Forest and Kassalong Reserve Forest are the last strongholds of bears where they could still be elevated to flagship species for the conservation of the mammalian communities living there.
As suggested by Garshelis et al. (Reference Garshelis, Pigeon, Hwang, Proctor, McShea, Fuller and Morin2022b) and McShea et al. (Reference McShea, Hwang, Liu, Li, Lamb and McLellan2022), we recommend the following: systematic monitoring of bears in eastern Bangladesh using advanced camera trapping and genetic methods; government-level support, encouragement and endorsement of bear research and conservation initiatives in these locations; the preparation of comprehensive human–bear conflict mitigation guidelines, implementation plans and rapid response teams; systematic documentation of human–bear conflict casualties at district hospitals in eastern Bangladesh and a centralized repository of these data at the Bangladesh Forest Department; stringent measures to protect the forest habitats in eastern Bangladesh and reduce poaching; and the implementation of specific actions for the welfare of captive bears in governmental and private collections.
Author contributions
Conceptualization, methodology, validation, data collection, writing: MA, SS; data collection, data curation, writing: SA, AGC, TZ; field survey: HD, SA, KNMDS; supervision: SS.
Acknowledgements
The 2021 camera-trap survey in north-east Bangladesh was supported by the Conservation Leadership Programme. We thank the Indigenous People of eastern Bangladesh and the field personnel of the Bangladesh Forest Department for their assistance; and Brian Crudge, Dusit Ngoprasert and Robert Steinmetz for their support with bear identification.
Conflicts of interest
None.
Ethical standards
This research abided by the Oryx guidelines on ethical standards. The camera-trapping work was a non-invasive survey carried out under the permission of the Bangladesh Forest Department and did not involve people. Images of people captured inadvertently on camera traps were stored in a protected database to ensure their privacy.
Data availability
The data supporting the findings of this study are available within the article and its Supplementary Materials.
Open access
