gunung leuser national park orangutans orang-outans sumatra indonesia indonesie

This article of our travel blog Heulys describes a two day trek in the jungle of Sumatra, more specifically in the Gunung Leuser National Park one of Indonesia’s largest parks. The discovery of the Sumatran jungle and its wildlife represents one the most exciting experiences we have ever had.

1. The jungle of Sumatra is an exceptional ecosystem

This tropical area is still largely intact

The Gunung Leuser National Park forms, together with Kerinci Seblat National Park and Bukit Barisan Selatan, the Tropical Rainforest Heritage of Sumatra. It is also recognised by UNESCO as a Biosphere Reserve.

But the natural balance of the park can be threaten by deforestation and deseases transmitted by humans. As Sumatra is developping ecotourism, this trek took place by respecting the natural environment and its wildlife.

Bohorok River near Bukit Lawang, trek Sumatra in the gunung leuser national park

Bohorok River near Bukit Lawang, Sumatra, Indonesia

This environment is rare and protected

It is the only place in the world, with Borneo, where free orangutans can be observed.

A rehabilitation center for orangutans was built in 1973 in the park. It was created to insert gradually in their natural environment the primates that had been injured, displaced from their housing or mistreated (some having known captivity as pets).
This activity of rehabilitation has stopped but it is still possible to observe these free orangutans in the rain forest.

2. Two day trek in the jungle of Sumatra

We leave Medan to join the charming village of Bukit Lawang, eastern entrance point of the park.  Upon our arrival, we feel a very peaceful atmosphere. The monotonous rumbling of the Bohorok River which adjoins the village stresses the impression of serenity.

trek village of Bukit Lawang in the jungle of sumatra, near the bohorok river

Bukit Lawang

Face to face with orangutans

The entrance of the park is located on the opposite bank of the river. Accompanied with our guide, we cross the river in canoe. In the forest, a ranger leads us towards the “feeding platform” of the orangutans. Quickly, some animals, regular guests of the place, are coming.
We remain speechless, watching these magnificent animals, whose behavior is so “human” that it impresses us. They strech, sway lianas, and feed in turn their youngs.
And their look…  Who observes who? We are completely mesmerized by this extraordinary show.
Look at the video. You will undestand what words cannot describe. Observe the young with the mother ! Magical and exceptional moments.

Orangutan of Sumatra in the Gunung Leuser National Park, Indonesia trek

Orangutan of Sumatra, Gunung Leuser National Park

Discover of the jungle of Sumatra

We leave the orangutans and then penetrate deeper into the jungle to observe other rare animals in the wild. This is the start of our discovery of what a rain forest is actually. The jungle of Sumatra is:

  • First of all, a noisy environment! The park is a true “wildlife reservoir”. The figures speak for themselves: besides orangutans, the park is the home to nearly 200 species of mammals, 350 species of birds, 190 species of reptiles. In two days, we met various families of primates (macaques, gibbons, Thomas leaf monkeys), varans and of course, we saw many birds. Other animals (tigers, elephants, etc…) are also present. They communicate with each other to mate, to find preys, to warn of predators… All these diverse and varied sounds produce a real concert of screams, singings and calls of all kinds.

primates in the gunung leuser national park, sumatra trek

Thomas leaf monkey – Gunung Leuser National Park

  • The ground is mountainuous (Mount Leuser culminates at 11,092 feet). It is also steep, slippery, forcing the hiker to cling to the roots and branches of the trees, to lianes, in brief to anything that stop from sliding.
  • The air is hot and saturated by humidity
  • Finally, the Sumatran jungle represents a highly diversified ecosystem, including zones of rainforest, mangroves swamps, rivers,… The vegetation is actually luxuriant and exceptional. Our guide told us that more than 8,000 plant species, including the Rafflesia, the world biggest flower, can be found in the jungle of Sumatra. We are impressed by the size of the trees which hide the sky.

gunung leuser trek sumatra Rain forest of Sumatra, Indonesia

Overnight camp in the jungle of Sumatra

In the evening, we spend the night in the jungle, by the Bohorok River. Our camp amounts to a plastic cover, stretched out between pickets, and under which we install our mat. Next to us, under their tent, the guides and cooks prepare our dinner: chicken and fresh fruits.
Difficult to sleep. More than the discomfort, the ceaseless rumbling of the river, the rumbling of thunder, the animals screamings form a concert which is unusual to us. But what a great camping experience !
The next morning, the weather is magnificent. After a breakfast again with fruits that a varan has tried to pinch us, we take back our exploration of the jungle of Sumatra, in search of orangutans, other primates, other animals in the wild.

hiking in the jungle of sumatra near the bohorok river gunung leuser national park

Camp in the jungle of sumatra

Playful return to Bukit Lawang

Late in the afternoon, we return to Bukit Lawang by the Bohorok river, in rafting. We cross the rapids of the river on inner tubes bound between them. What a thrill!
This very refreshing activity, of about forty minutes, is very popular, especially on weekends.


A trek of 2 days in the jungle of Sumatra is an unforgettable adventure, for all lovers of fauna and flora. Seeing the orangutangs and other animals, observing an incredible variety of flora, constitute a fascinating and moving experience.

Travel Information

Map showing our trek in the jungle of sumatra
Where is it? Bukit Lawang is located 55 miles west of Medan (3 hours drive).
How to get there? Means of transportation includes:

  • From Medan to Bukit Lawang, by bus in basic comfort, every 30 minutes.
  • In private vehicules rented at the Kuala Namu Airport (Medan) or proposed by hotels.
  • By air from Medan to Kutacane (internal flight of 30 minutes).

When to go? The climate is fairly even all year round, eventhough there is a dry and a wet seasons. During the wet season, rain usually comes at the end of the day.

Where to sleep? There are many guest-houses at Bukit Lawang, along the Bohorok river.
What are the conditions to visit the park? Be necessarily accompanied with a guide for any trek in the jungle. It is possible to reserve:

  • on a tour of Sumatra with a national trekking agency.
  • on the website of an agency.
  • locally at Bukit Lawang: Watch out, from Medan, guides put pressure on the tourists to offer their services at prohibitive prices. Take time at Bukit Lawang to compare the proposed rates, to question other tourists.

Other recommandations?
Respect the safety instructions of the park, adopt a responsible behavior with regards of the forest and the animals.
Besides, a trek in jungle requires:

  • a certain physical commitment, even if the hike does not present technical difficulties.
  • carry a lot of water,
  • arm yourself with anti-mosquitoes, wear long pants to protect from insects and leeches. Wear very good hiking shoes.
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