In 1887, 18 years before they divided Bengal into two, the British laid down a railway line through the Hoollongapar Gibbon Sanctuary, located on the south bank of the Brahmaputra river system in Jorhat district. While the railway line connected British tea plantations in Tinsukia with those in Jorhat and Dibrugarh, it divided the sanctuary into two unequal compartments—one roughly 150 hectares (370 acres), the rest roughly 1,950 hectares (4,820 acres)...