Guling Mulu National Park in Malaysia, commonly known as Mulu, is the jewel in the Malaysian national park system. It’s a tropical rainforest (receiving more than 15 feet of rain per year) with tall mountains, steep cliffs, dramatic, razor-sharp limestone pinnacles, a huge network of caves of all levels of difficulty, rivers to cruise, a tribal longhouse to visit and more than 20,000 species of animals and 3,500 of plants. Excursions range from boat rides on eight-passenger longboats and walk-through cave light shows to advanced spelunking and an incredibly rigorous, two-night camping excursion that requires rock climbing skills and a lot of stamina.

We chose a middle ground, with as many moderate activities as we could squeeze into two days in the park. These included a number of basic activities, such as an introduction into the park’s geology and biodiversity in the park’s engaging,wonderfully descriptive discovery center, a walk through the forest canopy along a half-kilometer skywalk and a birds-eye view of the forest and into the canopy from a 30-meter high observation tower. We walked a number of trails on our own and saw a few of the mountains, ravines and dramatic holes caused by the collapse of underground caves and the efforts of the jungle to retake the land. We also planned to participate in five additional ranger-led activities (rangers are required for entry into all of the caves).

Our first planned cave exploration was to be a four-hour tour of several stalactite- and stalagmite-filled chambers of Wind Cave, followed by a walk through part of the 36-mile long Clearwater Cave to explore the power of an underwater river that continually erodes and shapes the cave. This trek, however, fell victim to our unexpected Miri detour which cut a day from our trip to Mulu.  fortunately, we were still about to participate in four other delightful adventures:

• Sky Canopy Walk, a 480 meter,tree-based canopy walk that is 20 meters above the forest floor. The walkway, suspended among more than a dozen “emergents” (those relative handful of trees that tower 20-30 meters above the canopy, provides a great view of the forest below, and explains the many ways in which animals and humans have found for using the trees. Some of the more interesting facts, however, came from the guide and the interpretive signs along the path to the skywalk. We learned for example, the unique strategies specific insects employ to capitalize on specific plants, such as the way one beetle spreads saliva on yam plant leaves and how, over a few days when the beetle returns, the saliva neutralizes the leafs poisons and allows it to be eaten: how fig wasps’ entire lifecycle, from larval stage through the tome in which the female dies, revolves around a specific fig.
• Night Walk, a flashlight-based tour through a lowland forest where we heard a range of forest sounds, from all types of insects, tree frogs and geckos and saw fluorescent fungi, a pit viper and all types of giant spiders and insects and even a bright yellow sleeping bird. Joyce and one of the other women in our groups also had a less than pleasant rendezvous with some fire ants. They really do burn when they bite you and the bites are similar in itchiness as mosquito bites (which Joyce also was lucky enough to also get). Overall, we saw more wildlife than on our Bako might walk, but somewhat less than we hoped for. Our guide was pretty good at spotting different species, but not at knowing what they were.
• Lagangs Cave. A half-hour longboat cruise and then walk to the cave, where we donned helmets and headlights for a 45-minute clamber over rocks, crawling through tight passages and caverns filled with beautiful stalagmites and stalactites. Although the description claims it is easy and suitable for the entire family, the cave floor, on which you will be crawling on your hands and knees under stalactites and under stalagmites, is muddy and slippery. The cave is certainly beautiful, but exercise care and prepare to get muddy.
• Deer Cave, via a 5.5-hour, muddy, slippery, but beautiful walk deep into Deer Cave where we climbed, including one stretch with ropes and clambered over boulders covered in bat guano (bat poop), navigating rocks crossing underground guano-tainted steams and dodging the cockroaches and centipedes that made a steady diet of the guano. (Not a very pleasant vision, but you do get somewhat used to it.)

Why would we put ourselves through such an ordeal? First to explore the huge caverns and the lovely stalactites and stalagmites of one of the largest limestone caves on earth. Second to end up where we and the other two couples on the hike THOUGHT we would end up– in the Garden of Eden grotto with a lovely 30-meter waterfall that plunged over a shear limestone cliff into a crystal-clear pond in which we would take a swim. But as we learned from our guide when we reached our actual destination, that was the destination of a nine-hour trip of the same name that was not available that day. While we did reach a clean pond, we elected to not even try to go into the water due to the rocks we would have to navigate in bare feet. 

Still, we did enjoy the hike and our guide was one of the best nature guides we have had, pointing out, naming and explaining fascinating details about a number of beautiful animals (like the endangered, bright red-headed, phosphorescent green and black-striped wing Rajahbrooke butterfly) and less beautiful  animals (cave-dwelling blind catfish and giant blind cricket). Also, we exited the cave about 5:30; just in time to watch wave after wave of 2-3 million Wrinkled-Lip bats make their sweeping mass exit from the cave in search of eating two-thirds of their bodyweight in mosquitos (about 30 tons in total for all of the bats) that they will devour by sunrise and return to their cave to deposit more guano in anticipation of tomorrow’s hikers. Unlike other bats we have seen, these bats flew in an S shape line.

And then there were all the other fascinating rainforest facts we learned. For example:

• Only 5% of all the sunlight that shines on a rainforest makes its way through the canopy to the understory and only 1% reaches the forest floor.
• Although trees in tropical rain forests drop only a few leaves at a time, a total of more than 10 tons of leaves fall per hectare each year.
• Despite the huge volume of nutrients that fall onto and decompose on the forest floor and the volume of water that falls on it, it has poor fertility due to a combination of low sunlight penetration and frequent floods that wash the nutrients into rivers.
• Virtually every species of plant has its own seed dispersal strategy and many are dependent on unique relationships with a particular specie is of animal for fertilizing the plant and spreading its seeds.
• There are more than 20 million invertebrate animals in a typical hectare of rainforest.
• Bats, the only mammals that can fly (versus glide), account for 25% of all mammal species.
• Tiny mouse deer search our bat guano-filled streams as a source of salt,
• A leech (which generally causes no real harm to its host! and does not spread diseases), can consume 15 times its body weight at a time, and not feed again for months.
• If insects went extinct, many specie of plants would never be fertilized and many species of animals that rely on them for food would face shortages or die off. If bats were to go extinct, many other plant species would go extinct and the population of mosquitos and other flying insects would explode. If humans were to become extinct, the only species that would be negatively affected would be head lice!

While this made for a fascinating and very full two days, it was far from enough. Although it allowed us to do some basic splunkering (which we enjoy but are only out-of-practice novices), we would have liked to have done more, we would also have also appreciated if the description of our Langangs Cave splunkering trip explained exactly what was involved, so we could have prepared for it.

More regrettably, we were not able to get even a view of the rugged, geologically unusual Pinnacles section of the park–rugged, knife-like fractured limestone that are the remnants of large collapsed caverns. Seeing them requires a physically demanding, three-day, two-night hike that covers only 11.4 km each way, but the second day includes 1.2 km vertical assent with ropes required for part of it. And the descent is much more difficult, not to speak of dangerous than the ascent. Even if we had the gear and the time required for this expedition,we weren’t sure we would have been up to it.

However, the good news is that unlike Bako National Park, the accommodations were very comfortable and clean and the food was decent. Not great, but at least edible.