Captain Bingham was not the first to have heard of the tua yeua. The Thais, of course, spoke of it and one witness in the 1880s said he had seen one and it was too tall to have been a gibbon.
South of Thailand in Malaysia various types of apes or humanoids have been reported. Perhaps it was one of these, but, again, we cannot identify these with certainty either. However, it is known that Thailand once numbered the orang utan among its fauna. Could a population of these have survived as late as the 19th Century? And the question arises, could a population of this endangered species still survive in some part of Thailand rarely trodden by human feet, to this day?