From the 1960s until the 2000s there had been no confirmed sightings of the eastern black-crested gibbon and it was thought to be possibly extinct. In 2002 a small population was rediscovered by two FFI biologists in a karst forest of Trùng Khánh District, Cao Bằng Province, in northeast Vietnam.
From the 1960s until the 2000s, there were no confirmed sightings of the eastern black-crested gibbon and it was believed to be possibly extinct. In 2002, a small population was rediscovered by two FFI biologists in a karst forest of Trùng Khánh District, Cao Bằng Province, in northeast Vietnam.