It’s unclear when ancient humans first arrived on the shores of Sulawesi, a 71,898-square-mile Indonesian island west of Borneo. The oldest-known skeleton dates back to between 16,000 and 25,000 years ago, while some stone tools and rock shelters seem to have been assembled more than 118,000 years ago. Fossil bits from long-gone megafauna, whose quantity and concentration suggest they were hunted to extinction, indicate that other hominin specie…