Lush and volcanic, the Indonesian isle of Sumatra is a land of rugged tropical terrain and orangutan-filled jungles. Wedged between Java and the Malay Peninsula, the island envelopes the Leuser Ecosystem, one of the most biodiverse places on earth.

Over half the size of Switzerland, at 2.6 million hectares, the largest rainforest conservation area in Southeast Asia sweeps in the Gunung Leuser National Park — home to the orangutan plus three highly endangered large mammal species: the Sumatran rhino, elephant and tiger.

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Why choose Sumatra to see orangutans?

The Sumatran orangutan — The Pongo Abelii — is a species apart. Far fewer in number than the Bornean orangutan, the chance of seeing them in their native habitat is equally rare.

A dire warning was issued in April 2019 by animal charities in the UK: the Sumatran orangutan could be extinct within two decades. Critically endangered on the IUCN (International Union for the Conservation of Nature) Red List, it estimates their current population living in the wild at about 13,846.

Dwelling only in the forests of northern Sumatra, most of the remaining population live amid the tropical lowland rainforests, cloud-draped mountains and steamy peat swamps of the Leuser Ecosystem and its surrounds.

Sumatran orangutans have lighter red coats and thinner faces than their rounder Bornean cousins, but do have some similar traits — including one particularly surprising one, according to the WWF. Adult males have a beard and moustache, while adult female Sumatran orangutans also have beards.

The best time to see them in the wild is whenever you can. As with all tropical climates, Sumatra has wet (October to April) and dry (May to September) seasons; but due to climate change and regional unpredictability, the line between the two is becoming increasingly blurry.

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Where to see orangutans in Sumatra

Gunung Leuser National Park

Once present across the island of Sumatra and even into Java, the orangutan population has now been pushed back into the island’s north amid the coffee plantations of the provinces of North Sumatra and Aceh. Only some fall within the protected zone of the Gunung (Mount) Leuser National Park.

Despite being technically protected under Indonesian law, the extraordinarily life-rich Leuser Ecosystem — including the orangutans (and people) that live within it — continues to face threats of mining activities, palm oil, pulp and paper plantations. Only about a third of the apes live in internationally-recognised protected conservation areas.

For now, the only place geared to greet you for orangutan sightings/tours is the 7,927km square Gunung Leuser National Park, where the creatures dwell in lowland rainforests. The chances of seeing the orangutan here are high, together with other primates such as the leaf monkey, macaques and gibbons.

The rainforests, montane forests and peat swamps of the Leuser Ecosystem is the last place on earth where Sumatran orangutans roam free together with elephants, tigers, rhinos and sun bears — though the likelihood of seeing these animals is far less.

The main launchpad for the park is the village of Bukit Lawang, spread along the banks of the Sungai Bohorok river, on the eastern fringes of the park. The resort lies 90km west of Medan City, the main arrival point on the island by air.

Bukit Lawang actually grew up around the now-closed Bohorok Orangutan Rehabilitation Centre, set up by two Swiss women in 1973 with the aim of returning captive and orphaned orangutans to the wild after teaching them the art of tree climbing and nest building. Accommodation in Bukit Lawang is basic, but the whole village is geared towards orangutan tours.

Those travelling independently can also board a bus to Medan from the Pinang Baris bus station, but the relatively short journey will take up to four hours and coaches are not air-conditioned. Furthermore, there have been serious alerts about ticketing rackets at this station, with organised groups displaying aggressive behaviour towards travellers, pressuring them into paying higher than the going fare.

The orangutan experience
In order to enter the park, visitors must be accompanied by a licensed guide. The entrance fee is 150,000 Rupiah (£8) and travellers should be prepared for jungle trekking. It is possible to take day tours, but those looking for a more adventurous experience can choose overnight jungle camping stays or basic guesthouses, lasting from one night to four.

Visitors should be prepared to hike for several hours to reach orangutan nesting spots, but along the way you can spot Thomas Leaf monkeys, macaques and other apes. As you’ll be viewing orangutans in the wild, it’s vital that you follow the advice of your guides and respect the animals. Never feed them (this is so they don’t become reliant on humans) and keep a respectful distance.

Be aware that you are more likely to spot female Sumatran orangutans and their babies than adult males, who only visit the forest during mating season. Trekking at Gunung Leuser is relatively easy for those with decent fitness levels. Day treks are family friendly, although those with young children may find the heat and humidity an issue. Expect a day trek to last about eight hours in total.

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Key features

Close encounters with orangutans in the wild: Seeing the critically endangered Sumatran orangutan in its own habitat and spreading the word about conservation efforts.

Back-to-nature experiences: Overnight jungle treks offer the chance to sleep in bamboo camps in the rainforest.

Jungle trekking: On longer treks, experienced guides will introduce to the wonders of the rainforest. You may even be lucky enough to see the Sumatran elephant or tiger.

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