The Sumatran orangutan is one of the three species of orangutan, found only in the north of Sumatra. It is rarer than the Bornean orangutan but more common than the recently identified Tapanuli orangutan, which is also found on Sumatra (Wikipedia, general species account).
Males grow to about 1.7 m tall and 90 kg, while females are smaller, averaging about 90 cm and 45 kg. Compared with the Bornean species, Sumatran orangutans are thinner and have longer faces; their hair is longer and a paler red (Wikipedia, general species account).
Description: Wildlife of Sumatra guide, Wildlife of Everywhere (wildlifeofeverywhere.com); general species information paraphrased from Wikipedia (CC BY-SA)
Mammals of the World