Gunung Mulu National Park: a World of Caves


The karst landscape of Gunung Mulu was inscribed in 2000 as Malaysia’s second UNESCO Natural World Heritage Site. Among many natural sites already present in the prestigious list, Gunung Mulu easily stands out as it is one of the few that is inscribed on all four natural criteria set by the World Heritage Committee. These are: 1. it being an outstanding specimen for the study of geological processes, 2. it being a exemplary representative of ongoing ecological and biological processes, 3. it exhibiting a superlative phenomena of natural beauty, and 4.  it housing a natural habitat for in-situ conservation of biological diversity. 

How can something so fluffy be so deadly?! Some endemic insects in the park.
How can something so fluffy be so deadly?! Some endemic insects in the park.

Gunung Mulu National Park is very inaccessible, and going there really needs some effort. I arrived in Mulu on a plane from Kota Kinabalu, passing through Miri Airport in Sarawak first. This proved to be the most convenient — and expensive! 🙁 –way to reach the site compared to the 12-hour boat ride through the Mesilau River, or the 3-day trek along the Borneo headhunting trail in the mountains.

Entering Clearwater Cave. The underground river is so strong that the sound its rapids make echoes through out the cave.
Entering Clearwater cave. The underground river is so strong that the sound its rapids make echoes loudly throughout the cave.

I managed to explore various walking trails within the park, visit the indigenous Penan nomadic settlements (Penan people have the exclusive hunting rights in the park in recognition to their tradition; some of them are even the descendants of the notorious Borneo headhunting tribes), experience the longest tree-based canopy walkway in the world, enjoy the Paku waterfall all to myself (trekking “alone” some 2km through the forest!), and climb the Tree Top Tower hoping to see some wild animals in action. However, the real highlights of my trip were, of course, its show caves.

A local Penan living in nomadic settlements surrounding Gunung Mulu. He was about to go out hunting.
A local Penan living in nomadic settlements around Gunung Mulu. He was about to go out hunting.

In my 5-day trip into the jungles of Sarawak, I stayed in the humble Mulu Homestay just outside the entrance to the park.

The first set of caves I visited are the Wind Cave and Clearwater Cave. These caves are in Mount Api, and to get there requires riding a longboat passing through the Melinau Gorge canyon, stopping by the Penan village, and finally trekking along the karst mountainside.

One of the cave shafts (around 60m high/deep) in the Wind Cave. So, again, we were way below the face of the earth.
One of the cave shafts (around 60m high/deep?) in the Wind cave. So, again, we were way below the face of the earth.

Wind Cave is a personal favorite. The story behind its name is interesting – winds channeled to the cave, through its numerous shafts (eroded holes in the earth’s surface), can get really strong; hence, it is also named as the Cave of Winds. Its grand King’s Chamber, gifted with some of the best stalactites, stalagmites and pillar formations there are to find, will indefinitely hold a special place in my heart. As it was my first time to see cave shafts (I’ve seen four here), seeing one that drops close to 80 metres below the ground  was a stunning experience. From where I had been, the ground that we know is already way above me – yes, I went that deep below the earth’s surface 🙂

The beautiful King's Chamber in Wind Cave. A killer!
The beautiful King’s Chamber in the Wind Cave – the ultimate heartthrob for me!

The Clearwater Cave, on the other hand, boasts the record of being the largest cave network ever surveyed. Also, as much as I love Palawan’s Puerto Princesa Subterranean River NPthe real record of the longest underground river system actually belongs to the Clearwater Cave that spans over 170km in total length. The biggest cave chamber – the Sarawak Chamber – is also said to be connected to Clearwater. This massive cave network also displays a unique habitat for a rare one-leaf plant that only thrives at the cave’s mouth. At the end of the trek, I did not miss the opportunity to take a dip in the Clearwater river. I realized later on that I was the only one who braved jumping into the ridiculously cold river.

Rare one-leaf plants in the mouth of Clearwater Cave.
Rare one-leaf plants at the mouth of Clearwater cave.

The next set of caves I visited is that of the famed Deer Cave and adjacent Lang’s Cave, both of which are in the southern limestone karst hills of the park. To reach this part, visitors have to trek a total of 3kms from the park’s headquarter. Lang’s Cave is really small. It is so compact that one can even touch its ceiling, and get a close look at some ‘ongoing geological processes’ like dripstone activities, living stromatolites, and limestone (dis)colourations. Despite its size, this one is the most extravagantly furnished in terms of cave ornaments.

Dripstones in Lang's Cave. See the ceiling? Told you it wasn't that high.
Dripstones in the Lang’s Cave. See the ceiling? Told you it was not that high.

The nearby Deer Cave has the reputation of having the biggest cave opening in the world at 170m x 120m. It’s not superbly decorated as the others, but the inside is home to a totally alien ecosystem that is practically deprived of sunlight and regular air movement. The cave houses around 3.5 million wrinkle-lipped bats, a lot of creepy crawlies, several cave snakes, some freshwater shrimps and fish (this was a big surprise!), and more than a metre-deep sea of guano (bat droppings). One of the highlights of the Deer Cave would be the Flight of the Black Dragon in the afternoon. In consonance to natural rhythms of the jungle, all the bats would fly out at dusk to feed on insects, forming what appears to be like a black ribbon dancing in the sky.

Deer Cave: the profile of Abe Lincoln in the opening, and the sea of guano.
Deer Cave: the profile of Abe Lincoln in the opening, and the sea of guano.

During my entire stay in the park, I never got to see the bats leaving the Deer Cave despite patiently waiting for 3 hours every afternoon and always getting heavily soaked in the rain along the way. It was only then that I realized that it rains “all the time” in a rainforest!

All in all, it was a very pleasant trip into the forests of Sarawak in Borneo. Cave visits are only handled by certified heritage site guides, entry permits can be hard to obtain, all activities in the park should be recorded, information posters are everywhere, trails are signposted properly, and the site is well and strictly kept and administered (if you snap a leaf off a plant, expect some fine. So, better behave). These measures are all cognizant to the sensitiveness and vulnerability of this fragile natural wonder.

Maria Easters Sylvester, a guide from Kuching I made friends with, and I in the picnic area beside the Clearwater River.
Maria Easters Sylvester, a guide from Kuching I made friends with, and I in the picnic area beside the Clearwater river.

After having visited five UNESCO World Natural Heritage Sites  and several other natural parks in Asia, I have to admit that Gunung Mulu is one of the most well-managed and impressive natural sites I have seen.


Bernard Joseph Esposo Guerrero is a self-confessed cultural junky. Based in the Philippines, he has delivered several talks on tourism, destination promotion and management, and the importance of cultural conservation. As an independent heritage researcher and consultant, he has assisted and appeared in some features by the Euronews, NGC-Asia, and Solar News Channel's What I See travel show. He has traveled (both work and leisure) extensively in the Philippines and in Southeast Asia, and takes high interest in ticking off as many UNESCO World Heritage Sites as possible. So far, Gunung Mulu National Park in Sarawak, the Temple of Preah Vihear in Cambodia, and the Philippines' Apo Reef and Ifugao Rice Terraces are the best places he has seen in SE Asia. Instagram: theberntraveler

3 responses to “Gunung Mulu National Park: a World of Caves

  1. Hi Bernard,

    Absolutely beautiful photos.

    We visited a small national park in the north of Penang – nothing like this – and I recalled being absolutely drenched with sweat. Sure if was hot but the humidity levels were through the roof. Almost mind-boggling, as i felt like I was in a sauna the moment I stepped into the park, being under the canopy. Malaysia is one of the most diverse countries on earth for a reason; rain sustains life!

    The wind cave looked beyond awesome and I’m so happy that the folks over there have strict restrictions in place. Being fined and watched helps people respect nature, so we can preserve it, and more folks on earth need to preserve and work in harmony with nature, like the locals you mentioned who are allowed to hunt.

    They know to take care of the forest.

    Reminds me of the local fisherman here in Fiji. They pull back on fishing during certain seasons, not because fewer fish are available, but because they note levels are depleting. Great discipline they show, to keep harmony and balance, and to take care of their supply for future generations.

    Thanks so much Bernard.

    Tweeting through Triberr.


    1. Thanks, Ryan!

      Would you remember the name of the national park you went to near (or, is it IN) Penang? I’ve been to that lovely island too before and I really enjoyed those walks I had in the historic enclave of George Town.

      Yes, I think that the best approach to natural site administration would have to involve those in the grassroots to effectively manage one – after all, the locals would know best the area and how it behaves. Also, they give a “cultural” side to the landscape. I have another article here entitled, “Mt. Iglit-Baco, Philippines: Into the Savannas”; I also shared there how the local Mangyans use indigenous knowledge to their agricultural practices — pretty interesting and sustainable actually!

      Again, thanks for reading my article. I’ve gone through your page as well. Keep writing.


      PS. Maybe swing over to the Philippines soon?

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