Mulu: Tropical Caves and Forests

Our Borneo adventure continued with a visit to Mulu National Park, a land of deep tropical forest and deep tropical caves.

Riki’s thoughts…

The second segment of our vacation started with an early trip to the airport from our adorable culvert, followed by a two-leg flight from Kuching to Miri then to Mulu. We took a tiny cab ride (both in distance and in car size) from the airport to the Gunung Mulu National Park, a World Heritage Site. This is a place that Kelly has visited before. He and a great team did a collecting trip there a few decades ago. He noticed that it had gone through quite a few upgrades since he and the team were there last.

We were scheduled to be at the park for three nights, with a big overnight excursion to the Sarawak Cavern, the world’s largest cavern. Our first scheduled trip was the day we arrived, an afternoon hike to Lang Cave and Deer Cave. The park is so well-developed that the two-kilometer hike was entirely on boardwalk and concrete path, but it is through absolutely gorgeous rainforest. I had never been to a rainforest and was struck with the beauty and the noise. There was a frog that kept asking, “What?” but never gave time for us to repeat ourselves, along with a billion other night sounds.

Kelly loves caves, so I will leave the description of the caves to his literary genius. I will only mention that I felt somewhat fatigued and tired as we explored the caves, but I was able to find some roaches, a dead bat, and two earwigs that made Kelly very happy for reasons – something about a flea that lives on their legs. I enjoyed the cave tours and the hike out to them. We waited for a legendary exodus of the bats from Deer Cave, but the rain kept the bats indoors for the evening, so instead we walked back to the park headquarters in the dark.  Kelly loves being in the rainforest at night. This was my first time, and it was both intimidating and amazing. We found some gorgeous insects and some huge spiders with our headlamps. When Kelly handed me that humungous stick insect, I was hooked. I now love the rainforest at night, too.

That night, as we were eating dinner in the lovely on-site restaurant, I began feeling a bit, well,  bronchial. We were scheduled to leave the next morning for a 3-hour hike, two kilometers trekking up a river, and a one-kilometer scramble up huge boulders to the mouth of the cavern. I knew at midnight, when I woke up with a fever, a faucet where my nose used to be, and bronchial tubes that felt significantly narrowed, that I was indeed ill. I spent several hours working on my “you go to the cavern without me” speech.

In the morning, my deep voice and congested sinuses gave my condition away to Kelly. I launched into my prepared speech, but he was up and out the door to talk to our guide to cancel our excursion before I even got rolling on it. By mid-afternoon, he was also feeling sick. It would have been a miserable trip for him if I had convinced him to go without me. We spent the day exploring the trails around our bungalow and resting when our fevers spiked. Luckily, the restaurant served shakes, which were like life-nectar to us. We managed to hike back out to the amphitheater to watch the bat exodus. We were not disappointed. It was beyond amazing!! Kelly caught it in some videos. Enjoy! 

The next morning, we scheduled a trip up-river in a longboat to a village and two more caves. The village had a little artisan collective. We enjoyed looking at all the handmade wares, but did not buy anything, though the blow guns and set of darts were tempting. The first cave was an intense 200 steps up to the mouth, and 1000 steps through the cave. We, despite our colds, were the only ones in our tour group to make it to the top without stopping. These two 50+ agers, I guess, are used to hiking. Why does 30 minutes on an orbital make me feel like dying, then?

The caves, Wind Cave and Clearwater Cave, were beautiful, and well worth the effort to reach them. We were rewarded after the second cave tour with an invitation to swim in the river. I was pretty scared to do that, since I am weak swimmer, but I powered past my fear and enjoyed the dip in the clear and not cold river.

After a good afternoon nap, we hiked a bit through the rainforest until an evening rain drove us indoors, where we were entertained by some geckos fighting over a huge insect on the windows (outside) in our cute and comfortable bungalow. We went to bed, feeling both ill and satisfied.

The next morning, we were able to take a leisurely time wrapping up our time at Gunung Mulu. Our flight was early afternoon. It was hard to say goodbye to this lovely place, but more adventures were calling, and we had to answer. Goodbye for now, bats and caves and millipedes. God-willing, we will be back, and this time, we will see the Sarawak Cavern!!

Kelly’s thoughts…

I visited Borneo about 10 years ago on a collecting campaign with my colleagues.  On that tripe, we worked at a national park near Kuching and Mulu National Park.  It was an amazing experience, and when I was considering a new adventure for Riki and me, after our epic adventure to Chad last year, Borneo seemed like a great choice.

After our couple days near Kuching and Bako Park, we took a short flight to Mulu National Park.  This is an amazing region of dense tropical forest with higher elevation mountains represented by sandstone and limestone uplifts.  The limestone is heavily weathered by the intense precipitation into massive cave systems, some of the largest and most extensive in the world.

We got sick.  Like, really bad fevers and such.  We had planned to hike out to the Sarawak Chamber.  The Sarawak Chamber is a space in Good Luck Cave that is the largest enclosed space known on the planet.  The space could fit 40 747 airplanes without overlapping.  It’s huge.  I have wanted to visit it since I first learned about it back in high school when my friends and I (including Riki!) were heavy into caving.  We had arranged to hike out to the cave to see the Chamber, but because we were really sick, we decided to bail on that plan.

But that was okay.  We ended up exploring the tropical forests of Mulu, visited some other cave systems, and saw millions of bats flying out of Deer Cave.  Even though we were diseased and feverish, we had a great time finding birds and reptiles and caves and arthropods and great milkshakes and food in Mulu Park.

I was so impressed with Riki.  So many new things… she explored tropical caves, she was out in the rainforest at night looking for critters, she got fully immersed in a tropical stream, and she did it all while pushing through a nasty cold. She is a wonder and a wonderful partner.

The Deer Cave bats were amazing… some 15 minutes of bats streaming out of the cave, millions of bats that spread out over the forest every evening to eat moths and other flying insects.

Inside the cave, which is huge, we found massive amounts of guano which sometimes meant breathing a lot of serious ammonia.

Inside these caves the bats have a specialized parasitic earwig species, Arixenia esau.  This incredible insect scrapes the skin of bats to eat.  Some 10 years ago, when I was here, we collected several hundred specimens of this species. Later, we observed that a species of flea was attached to the specimens.  These fleas were “phoretic” on the earwigs, they rode around on them to transport from bat to bat.  We even published a paper on this phenomenon, my only paper on earwigs, fleas and bats!  Riki found a couple of the earwigs, and I was able to film them.  What a great wildlife opportunity!

We found a lot of other wonderful wildlife including millipedes, frogs, dangerous caterpillars, amazing lizards, giant stick insects, and amazing butterflies.

Even sick and kinda miserable, we had a great visit to the rain forests of Mulu.