The Sumatran orangutan (Pongo abelii) is one of the two species of orangutans. Found only on the island of Sumatra in Indonesia, it is rarer than the Bornean orangutan. Its common name is based on two separate local words, "orang" ("people" or "person") and "hutan" ("forest"), and translates as 'Man of the Forest'. Male Sumatran orangutans grow to about 1.4 m (4.6 ft) tall and 90 kg (200 lb). Females are smaller, averaging 90 cm (3.0 ft) and 45 kg (99 lb). Compared to the Bornean species, Sumatran orangutans are thinner and have longer faces; their hair is longer with a paler red colour.
Orang utan of Sumatera, can be visited by trekking 3 hours into the Gunung Leuser National Park in Bukit Lawang. To see orang utan, trekking alongwith a local guide is needed.
If you visit north Sumatera, then you will have to land at Kualanamu Airport and you can direcly go to Bukit Lawang and than from Bukit Lawang, do trekking into the jungle for 3 hours. Besides Orang Utan, you can visit other animals such as thomas leaf monkeys,birds,ants, gibbon etc.