Within Borneo’s Gomantong Caves – slippery with teeming insects, bird droppings and guano from two million bats – fine dining is likely far from the mind. But overhead a perilous harvest ensues for the key ingredient of Chinese bird’s nest soup. By Linda Jaivin.

Borneo’s Gomantong Caves

Inside the Gomantong Caves, in Sabah, Borneo.
Inside the Gomantong Caves, in Sabah, Borneo.
Credit: Debbie Monique Jolliff / Alamy Stock Photo

The road has just entered the jungle, when our driver suddenly pulls over. Just ahead, a crested serpent eagle has swooped on what looks like a small snake. We pour out of the van to watch, saluting the fierce-looking raptor with our smartphones. It flies up onto the branch of a tree, its prey wriggling in its powerful claws. But when the snake turns out to be a giant worm, the eagle spits it out in apparent disgust. Even a creature that eats snakes for a living has its limits.

Us, not so much. Our destination is the Gomantong Caves. The limestone caves of Sabah in northern Borneo, not far from the Kinabatangan River, are 65 million years old. They are also home to up to two million wrinkle-lipped bats, billions of cockroaches, giant rats, poisonous centipedes and cave crabs that live in streams of guano.

In the parking lot of the Gomantong Forest Reserve, our guide, Suhaili, a Bornean man with a puckish sense of humour, hands out hard hats. We’ll need these, he explains cheerfully, to protect us from chunks of guano, dead bats and dying birds, not to mention cockroaches and other invertebrates, any of which could come pelting down at any moment from the cave’s 90-metre-high roof.

Next, he passes out latex gloves: “One each,” he says. “Right hand only.” The boardwalks that will take us on a counterclockwise circuit of the lower cave are notoriously slimy. Should we slip and need to grab onto the handrail, the glove will keep our hand from direct contact with layers of bat and bird guano and the swarms of insects that feed on it. The final item in our goodie bag is a hospital-style mask, for the ammoniac stench from the metres-deep mountain of guano covering the cave floor. I try mine on, and between the fierce wet heat of the surrounding jungle and my own sweat, it instantly disintegrates, hanging off my ears in pieces. Suhaili grins and reassures me: “They’re not that effective anyway.”

The Gomantong Caves certainly put the grot into grotto. As unlikely as it may seem, they are also a prime source of one of the world’s most expensive delicacies. The caves are home to thousands of birds that build their nests with their own spit – edible-nest swiftlets, Aerodramus fuciphagus. Their gummy spit-nests are the key ingredient in Chinese bird’s nest soup. Chinese tradition has it that consuming swiftlet nests – typically prepared with sugar, as a dessert – makes the skin glow, energises the system, improves focus, kickstarts the libido and helps you live longer. If you believe the claims on commercial websites, it’s recommended for pregnant women, stressed-out students, people who work late, women in menopause, the elderly, “those suffering from chronic ailments, those who are ill and those who have recuperated”. Oh, and it cures cancer, too.

Once the food of emperors, today, it’s a status dish on the menu of China’s burgeoning middle class. Many make do with nests from artificial “swift houses” across South-East Asia. These come with a moderately affordable price tag but gourmands complain of a slight mouth-feel of sawdust. There are reportedly some 60,000 swift farms in Malaysia alone. But those for whom, say, $A2300 a kilo is not a problem, prefer their nests to be cave-to-table. The Gomantong Caves have a reputation for producing some of the best, if not the best, in the world. Legend has it that it was in Borneo that the great 15th-century eunuch Admiral Zheng He first worked out that the nests were edible. The rest is culinary history.

Unregulated harvesting here and elsewhere, including stealing nests before the eggs inside have hatched, however, threatens the survival of the swiftlets in the wild. In some places, they’re already extinct. Here, harvesting of the nests is strictly regulated and permitted only after the young birds have hatched. Suhaili tells us the trade in nests from the Gomantong Caves earns Sabah more than 60 million Malaysian ringgit ($A20 million) a year. This may be only a small proportion of a global industry reportedly worth $US5 billion a year. But it’s a great source of income for Malaysia’s poorest state.

The benefits are not just economic. Wild swiftlet populations require a fair whack of wilderness to sustain them. The palm oil plantations that have destroyed so much of Borneo’s remarkably biodiverse environment, posing an existential threat to the orang-utan and other native species, knock up against the edge of the Gomantong Forest Reserve. But they can’t come in. And so nearly 3300 hectares of rainforest is saved.

We troop along behind Suhaili on the raised boardwalk that leads through the dense jungle to the caves. Butterflies flutter across our path. A yellow-and-black striped millipede the size of a man’s finger twitches its orange antennae at us. Vines tangle, birds flit, squirrels scoot. From deep in the jungle come clicks, cheeps, squeaks and a rustling. Suhaili tells us about a giant python, some eight metres long, that not so far from here gobbled up a man, gumboots and all.

Finally, we emerge in a park-like clearing. Ahead looms the entrance to the cave. To the right of the path is a kind of wooden longhouse on stilts, home to the security guards and harvesters. Someone is cooking. Strewn on the ground outside are baskets, ropes, ladders and bamboo poles. Harvesting is dangerous work. There’s no safety net over the guano pit with its hidden rocky outcrops and boulders, and not a few have fallen to their death here. At the mouth of the cave is a rock formation that, viewed from inside, looks eerily like a human face. It’s where, at the start of the harvest, workers traditionally sacrifice a goat to pray for their safety.

We’ve just stepped inside when the smell slaps me across the face, though judging from the others’ expressions, Suhaili is probably right about the masks. We crunch our way along the slimy, infested boardwalk, extinguishing countless invertebrate lives as we go, not daring to stop lest the frenetic underfoot hordes make a dash for freedom up our trousers. We point our smartphone torches at the cave wall: circles of light illuminate kinetic, shimmering masses of cockroaches and centipedes. Rats scuttle in and out of holes in the cave wall.

The most horrifying sight is that of two little makeshift wooden huts, one propped up in the guano field, the other, in a nook in the crawly cave wall. There’s a third one in the upper cave, where the swiftlets that make the white nests considered the most valuable have their colony. These are security stations. Nest poaching is an ever-present threat. “Worst job in the world,” Suhaili says. He points out the mosquito netting that covers every door and window: “That’s for cockroaches.” The guards, he says, earn 15 ringgit a day ($A5). Harvesters, by way of contrast, can earn up to 10,000 ringgit ($A3300) over a period of less than two weeks. The guards get a bonus during harvesting season, but the main perk of the job is that if any nests fall down, they get to keep and sell them. According to Suhaili, guards rarely stick it out more than three years; some stay only two days before fleeing.

 Bat excretions fall like gentle rain, plop plop plop. 

There’s something on the walkway. It’s a solitary gumboot. “The python!” We hoot, our laughter tinged with hysteria.

Back in the fresh air, we shed gloves and hats and retreat to the benches of a park pavilion that affords a view of the cave entrance, the thickly forested mountain, and a sky full of cotton-puff clouds. My hands are covered in black spots. I panic before realising that the cover of my Moleskine notebook has half-dissolved in the heat.

We are waiting for dusk. This is the moment when the swiftlets return, bellies full of insects, and the bats fly out for the jungle’s second sitting. A huge helmeted hornbill takes up a post in a tree by the cave entrance, waiting for dinner. Swiftlets are on the menu. High up to our right, a red leaf monkey shows its melancholic face. Finally, the spectacle begins. In ones and tens at first, and then in their hundreds and thousands, the wrinkle-lipped bats erupt from a hole at the top of the mountain like lava. They stream into the sky, a lacy black ribbon. A bat hawk, wings outstretched, dives towards them. The ribbon knots, as the bats make a bait ball in the sky before flinging themselves in another direction. Another hawk attacks. The bats switch direction again. And then, on the mountain, a flash of orange fur and the most awesome sight of all: an orang-utan mother and baby in the wild. From the grotesque to the sublime.

This article was first published in the print edition of The Saturday Paper on August 4, 2018 as "To the bat cave".

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