Orangutan | Smithsonian’s National Zoo and Conservation Biology Institute https://nationalzoo.si.edu/animals/orangutan
Orangutans are the largest arboreal mammals and the most socially solitary of the great apes. All three orangutan species — Bornean, Sumatran and the newly discovered Tapanuli — are critically endangered, primarily due to habitat loss.
Sumatran and Tapanuli orangutans are in imminent danger