How far westward? Revisiting the distribution of Arctonyx badgers in the westernmost global range

Bangladesh delimits the westernmost range of Arctonyx badgers, but their presence in the country is not completely understood. The whole of Bangladesh is reportedly home to the northern hog badger (A. albogularis); however, there is no valid record to date. The greater hog badger (Arctonyx collaris), its larger congener and a globally vulnerable mustelid, has three valid records. This work, between 2001 and 2021, traced 28 records (all of A. collaris: 20 from literature review and social media, 8 from camera-trapping) in Bangladesh including four rare cases of erythrism and seven conflict incidents. All but five were from mixed evergreen forests of southeast Bangladesh, the known A. collaris range. One record was from wet deciduous forests of northern Bangladesh (bordering Meghalaya, India), a region not previously marked as an A. collaris range. In 2021, from 4436 trap-nights of sampling, 17 notionally-independent events (all night-time) were obtained. This produced the first evidence of A. collaris in northeast Bangladesh, a region that borders the Tripura Hills, India (where it was first recorded in 2020) and belongs to the Indo-Burma biodiversity hotspot. The work proves the existence of relict populations whereas the absence of A. albogularis signifies a re-assessment of its westernmost distribution.