We asked Chris Draper, program manager for captive wild animals at the Born Free Foundation in the U.K., to comment on the photograph.

"It is hard to say too much without the wider context and knowledge of the enclosure," he told The Dodo. "[But] the picture presents a striking contrast between the zoo visitors and the orangutan: a moment's interest and comedy for the visitors and a lifetime's captivity for the orangutan."

In the wild, Draper explains, orangutans are almost exclusively arboreal - "finding safety and comfort in the trees." Yet, he continues, "here we see a situation where endless streams of visitors may file past at eye level with this intelligent and sensitive ape."

Sumatran orangutans are critically endangered, with no more than 7,300 left in the wild.

"It is difficult to imagine how exhibiting the orangutan in this manner is helping to conserve wild orangutans," Draper notes. "Will the visitors become ardent conservationists or even reconsider their use of palm oil - the production of which is a significant contributor to the destruction of orangutan habitat - having briefly laughed at an ape in captivity?"

"Something tells me," he says, "it is unlikely."