Rarest great ape

The rarest species of great ape is the Tapanuli orang utan Pongo tapanuliensis, which was formally described and named as a new species in scientific literature as recently as 2 November 2017. It is known from just a single but discrete population of around 800 individuals occupying an area in northwestern Sumatra, Indonesia, of no more than approximately 1,000 km², and is officially categorized by conservationists as Critically Endangered.

It differs from the more northerly Sumatran orang utan P.abelii not only genetically, as revealed by comparative DNA analyses, but also morphologically, possessing a relatively smaller head, flatter face, pronounced moustache and frizzier fur.

In addition, its diet is more diverse, and the long vocal calls of the males are audibly different from those of male Sumatran orang utans.