The biodiversity hotspot you must visit now, before it’s too late

This is a proper downpour. The volume intensifies from a patter to a roar, as though at the turn of a dial. Cue the now-familiar frenzy of rummaging as we unpack waterproofs, cram cameras into Ziplock bags and hunker down in the open truck.

Only our trusty guide, Henry Sappingi, remains unbowed. Sitting cross-legged in a spare tyre on the cab roof, he continues to sweep his spotlight over the dark trees, illuminating only a relentless blizzard of rain.

Buy hey, this is rainforest: the clue is in the name. And lowland Borneo has the most biodiverse rainforest on the planet, its wet, tropical fertility responsible for the very wildlife that brings us here. We shouldn’t complain when the forest does its thing.

Besides, it doesn’t last long. After 20 minutes, the white noise dwindles to an erratic, drip-drop spatter. Heads emerge turtle-like from dripping ponchos as the forest chorus strikes up again: a surround-sound symphony of whistles, clicks and chirrups as frogs, katydids and other nocturnal tunesmiths swing back into life. Overhead, the stars resume their twinkling.

The setting for this nocturnal drenching and (almost) drying out is Deramakot Forest Reserve, at the heart of Sabah, Malaysian Borneo. I am here on a 12-night trip with wildlife tour operator Naturetrek, concentrating on the lesser-known creatures that are active only after dark – which means most mammals.

Hence the nightly spotlighting drives, heading out after dinner and often returning after midnight. It is a routine that is fast resetting our body clocks.

I say “lesser-known” creatures because, where Borneo’s wildlife is concerned, it is often hard to see beyond orangutans. These charismatic apes dominate the ecotourism agenda – and because they are easily seen at rehabilitation centres along the coast, relatively few visitors investigate the wealth of other wildlife that inhabits the forested interior.

Meanwhile, these precious forests are fast disappearing, swept away by the relentless tide of palm-oil plantations. A wider awareness of their importance might just help save them.

Here in Deramakot, the nocturnal biodiversity is certainly mind-boggling. As the truck rumbles onward, we are once again glued to Henry’s beam as he sweeps the darkness, fishing for eyes. Soon he gets a bite: twin pinpoints of reflected eyeshine high in the canopy. My binoculars reveal a lithe, cat-like creature staring back.

The bandit mask and long tail identify it as a small-toothed palm civet – an arboreal hunter of lizards, birds and other treetop critters, though currently tucking into some wild figs. Spooked by our attention, it slips away through the branches, tail flowing behind.

Next up, a slow loris. This small, tailless primate clambers deliberately through the foliage, reaching for each handhold with slow-mo precision. Its endearing appearance – teddy-bear body; huge saucer eyes – belies a secret superpower: this is one of the world’s only mammals with a toxic bite.

With the rain holding off, the sightings continue: a colugo, or flying lemur, clinging like a tea towel to a palm trunk; a foraging binturong, or bearcat, showering rainwater from the canopy; a ghostly-white moonrat fossicking in the verge.

It’s not the wall-to-wall wildlife of an African safari – there are long periods of nothing – but everything we do find feels special. And plucking sightings from the darkness by eyeshine alone is like panning for gold. Occasionally, something crosses the track – one Sunda leopard cat sits tabby-tame in our headlights – but more often, we rely upon Henry’s apparently supernatural ability to spot the invisible.

Soon that roar comes again. Out go the stars, down comes the rain and on go the ponchos. I make like a loris, hunching into immobility as the water streams down my head and shoulders and pools on my lap. Like any good rainforest denizen, I am learning the drill.

In addition to the mammals mentioned, we have seen night birds such as buffy fish-owls; a pageant of frogs, including a fabulously camouflaged Malaysian horned frog; and several snakes, notably an emerald-green Borneo pit-viper and an 8ft-long dog-toothed cat-snake (now there’s an oxymoron), its liquorice-slim coils winding sinuously up the bank.

Larger creatures also roam these forests: sambar deer, sun bears, even elephants. Whisper it quietly, Deramakot offers probably the best chance anywhere of spotting a clouded leopard. Sightings are rare but regular. “Never say never,” says Henry, who has had multiple encounters, “but we have to be lucky.”

The prospect of encountering this mythically elusive cat quickens the heartbeat each time eyes appear in the beam.

After our nocturnal exertions, we expected a lie-in. No chance. Deramakot’s animals won’t spot themselves. Thus, after early morning coffee and toast, we are back in the truck.

Dawn lifts the veil on a world we can only imagine after dark. Exuberant birdsong replaces the mechanical night chorus; night’s shadowy, two-dimensional backdrop becomes a sunlit cathedral of green, with huge, lichen-splashed tree trunks supporting a canopy festooned with ferns and epiphytes. Gaps expose longer views – forested hillsides receding towards a blue-haze horizon.

With last night’s mammals now tucked up inside their holes, birds become the focus, from bulbuls in the undergrowth to hornbills lurching through the canopy and eagles circling the blue.

Borneo’s endemics are the jackpot here, and Henry finds us such coveted beauties as Bornean bristlehead and black-crowned pitta – the latter a jewel of a bird whose plaintive whistle rises from the understorey like a slow-boiling kettle.

Deeper in the forest, we also hear louder whistles – gently questioning, at first, then accelerating to a maniacal whooping. These are not avian, it turns out, but the territorial calls of Bornean gibbons.

Descending to walk the track, we glimpse a family party hurtling hand over hand through the canopy, one infant clinging to mum’s belly as she leaps treetop gaps with terrifying abandon.

Further down the track we also spy the old man of the forest himself: a mature male orangutan perched some 100ft up in a fruiting breadfruit tree. He is shy at first, theatrically covering his face with his hands, but soon resumes his breakfast. Through Henry’s telescope we admire his shaggy coat, dextrous fingers and impressive facial flanges.

This truly wild sighting feels more authentic than our encounter with habituated orangutans at Sepilok Rehabilitation Centre back on day one. Out here, finding one is much harder work, the animals behaving with the natural caution you would expect. Meeting this individual is thus a thrilling moment. It is also a poignant one.

With 50 per cent of Borneo’s rainforest lost between 1973 and 2015, the Bornean orangutan is today critically endangered. Sepilok is undoubtedly doing a fine job, rescuing injured or orphaned apes left homeless by habitat destruction, but this species has no future unless its forests are saved.

In this respect, Deramakot offers hope. This forest reserve is managed for both logging and conservation. Since the 1990s, however, it has pursued a policy of Reduced Impact Logging, which means removing trees selectively to minimise damage to the surrounding vegetation, soil structure and water quality.

It is a sustainable alternative to clear-felling, as the forest’s prolific biodiversity attests, and a model that points a way forward for Borneo’s forests – just so long as those palm-oil plantations advance no further.

I learn all this from a display back at reception. It is here that we convene for meals, briefings and the daily updating of our sightings list – Henry confirming which particular treefrog or tailorbird species we spotted on the last drive.

I’m intrigued by the microphone and drum kit in the corner: this working camp in the heart of the rainforest doesn’t seem an obvious party venue. Perhaps the gibbons and orangutans drop by for karaoke when the guests are gone.

Downtime is an opportunity to explore the camp. Fabulous butterflies, including such hand-sized beauties as great mormon and golden birdwing, drift along the forest edge, and any stroll can bring a new sighting: some in our group spy otters down by the river.

But the heat and humidity are sapping, and catching up on sleep generally seems wise. While we snooze, our litter of backpacks, boots and waterproofs dries quickly outside the chalets. By late afternoon, however, thunderclouds are massing, promising another night’s drenching.

On our final night drive, the rain holds off. Were this an Attenborough documentary, the promised clouded leopard would no doubt now, finally, appear (“Just as we were packing up to leave” etc). Sadly, no such luck.

But we do manage a few new species, including a banded civet – our fifth and most handsome civet species – and, even better, a small family group of elephants. The shy pachyderms lumber down the road ahead then crash off into the forest, trumpeting their outrage at our intrusion.

The following afternoon finds me again exploring the forest but this time by boat. We have travelled 75 miles east from Deramakot to spend our last three days at the Kinabatangan Wetland Resort – a gorgeous lodge arrayed along wooden boardwalks above the flooded forest. Henry, together with resort guide Max, is combing the riverbank for wildlife.

Wildlife-watching along the Kinabatangan River is a dream. We drift with the current, enjoying whatever we spot along the banks or simply watching the shifting cloudscape overhead.

At dusk, proboscis monkeys crash through the branches at their riverside roosts, the alpha males flaunting their preposterous conks. Below them, estuarine crocodiles bask on sand bars, while sea eagles, kingfishers and other water birds grow our list. There are orangutans here, too.

One morning, down a side creek, we meet a large male feeding on the pulpy hearts of nipa palms at the waterline. Sunrise gilds his shaggy limbs as he casually demolishes the vegetation. I want to warn him about the crocs, but I guess he knows.

Back at the lodge, the free Wi-Fi – unavailable at Deramakot – reconnects us with the outside world. For me, it is a mixed blessing, blunting my sense of wilderness. But when Max shows me his photos of the 16ft reticulated python spotted last month on the boardwalk, I am reminded that this remains a wild place; and that, left intact, Sabah’s forests will always have their secrets.

Of course, even Wi-Fi can’t control the weather. On our final evening cruise, we take shelter under a canopy of riverside branches as the heavens open. When the rain stops, we emerge to find fireflies lighting up the bushes like Christmas trees. It is magical; for some, almost spiritual.

But Henry, ever mindful of the list, is already rigging up the boat’s spotlight for a final shot at those elusive nocturnals. “Clouded leopard?” I quip. “Never say never,” he grins.

Essentials

Naturetrek offers Borneo’s Mammals: Deramakot Forest Reserve, a 14-day wildlife holiday to one of Borneo’s best mammal-watching destinations, from £4,695. This year’s tours depart June 4, July 4, Aug 2,  Sept 1 and Oct 1. There are several more departures in 2025; email tom@naturetrek.co.uk for details