What you will see, if you look carefully, are massive strangler figs looking poised to walk on their roots like Ents from The Lord of the Rings, or prettily patterned fungi creating works of art amid the leaf mould, or delicate orchids blooming colourfully in the gloom created by the thick canopy of leaves, or great armies of ants on the march along fallen branches.
During a cruise around Borneo on the expedition ship Orion II, we had the chance to explore several jungle national parks, all different and all fascinating.
At Tanjung Datu National Park, for instance, four of us wandered slowly along the Pasir Antu Laut Trail, managing to make its 2.7km last about 3.5 hours, pausing every few metres to admire some ornamental bracket fungus, a particularly twisty liana, a tall, thin tree supported by a massive set of buttress roots, or a butterfly with elegant black and white patterns on its wings.
There were certainly animals around. From time to time we heard monkey calls and the birdsong was superb. At one point I heard the beating of heavy wings overhead and caught a glimpse of the massive black shape of a hornbill. On another occasion I spied a small, dark brown squirrel poised unmoving on a branch above the path.
There were plenty of signs of pigs rooting and a group on another trail actually saw "a particularly ugly" Borneo bearded pig.
Down on the beach, which served as our return pathway, three sets of tracks showed where green turtles had come ashore to lay eggs during the night (the park staff dig the eggs up and rebury them in safe enclosures). In a cave at one end of the bay, dozens of tomb bats swooped around us while we explored its recesses.
But it was just as interesting to watch a route march of thousands of large, brown, ant-like creatures carrying white eggs - our guides later had an argument about whether they were termites or ants - a bright orange fungus glowing in the gloom, a magnificent yellow and black butterfly floating just under the leaf canopy, or one remaining flower from the night-blooming putat tree, whose glorious pink and white blossom produces a poison used to kill fish.
On the island of Pulau Tiga, we found the same incredible biodiversity ... plus mud. That was partly because of the heavy rain that fell as we landed from our zodiac, making the jungle track a bit slushy. But it was also because the island was formed by a volcanic eruption as recently as 1897 and there's still a sort of mud volcano in the jungle where crazy people like me can have a soak.
It was a pretty bizarre experience to slither our way into a couple of pools of warmish, grey, sticky mud - should be good for the skin, I thought - in the middle of the jungle. It was even more bizarre to jump out of the pool covered with grey gunk and run about 500m down the jungle track to see some macaques snacking on fruit in the tree.
And, most bizarre of all, the mud was so sticky that afterwards it took about half an hour to wash the stuff off in the warm waters of the South China Sea.
But along the pathway to the mud volcano there was more of the profuse rainforest life to enjoy, including more amazing fungi and some even bigger ants carrying their eggs off to pastures new.
It was much the same on the island of Pulau Lakei. The first boatload of passengers ashore apparently spotted a macaque disappearing into the trees. And as we walked the trail across the island, we could hear the grunting and crashing of proboscis monkeys hidden in the undergrowth.
But the absence of animals was more than made up for by the profusion of orchids and pitcher plants. If you walked slowly and looked, there were lots of shyly beautiful blossoms hiding behind the leaves. And we found three varieties of pitcher plant.
The island's particular claim to fame is the grave of Datu Haji, apparently a famous strongman, still venerated by locals. Walk down a wooden staircase from the spot where a small hut shelters his resting place and you come to a tranquil pool with some mysterious writing on the stone bottom, which Datu - such was his strength - is said to have carved with his bare fingers.
But it was the pitcher plants I kept going back to. Some were as much as 5cm across and, looking inside, I could smell the perfume they used to entice insects with the promise of nectar, see the waxy interior which even insects' legs slip off, examine the hairs which stop victims from climbing back up and see the pond of liquid in which they are eventually drowned and then dissolved to release their nutrients.
Mark, who is clearly fascinated by pitcher plants, told us there were dozens of different varieties in Borneo, including, in the highlands, a giant version holding four to five litres of liquid and capable of catching rats and even bats. "They tend to grow in areas where the soil is too poor for ordinary plants to survive."
Mostly the plants we found were green, but some were turning a beautiful red colour as they aged and it was one of these that really caught his eye. "Look at that," he said. "It's the most beautiful pitcher plant I've ever seen."
And to demonstrate the depth of his admiration, he puckered up.
CHECKLIST
Getting there: Singapore Airlines flies up to three times daily from New Zealand to Singapore, and then beyond to Bandar Seri Begawan five times a week. The airline's regional SilkAir flies to several destinations in Borneo, including three times a week to Kuching, daily flights to Kota Kinabalu and six flights a week to Balikpapan.
Getting around: Orion II has a range of Borneo departures next year in January-February and again in July-October. Ten-night fares start from $10,100 per person.
Further information: Call Orion Expedition Cruises on 0800 444 462 or see your travel agent.
Jim Eagles visited Borneo with help from Singapore Airlines and Orion Expedition Cruises.
