Native longboats on the Melinau River below take visitors to the Wind and Clearwater Caves hiding high in the limestone cliffs further up-river.
We climb to the start of the 480m-long Mulu Canopy Skywalk, the longest tree-based walkway in the world. It’s 20m above the dense jungle floor, but you walk through the canopy’s interior rather than on top of it. The walkway shakes and moves as you traverse each of the 15 sections, just two people at a time. If you hear a loud slow flapping above, look quickly and you just might see a Rhinoceros Hornbill, with its distinctive yellow bill, flying overhead.
Langs Cave has a magnificent variety of stalactites and stalagmites, but it was the Deer Cave just around the corner that really impressed. Discovered in 1977, it is the world’s largest show-cave. Two kilometres long and never less than 90m high and wide, with the main chamber 174m wide and 122m high, it was the shelter for hordes of deer long gone.
Today, around four million tiny bats roost here. They produce guano, a pungent dung used as fertiliser. At about 5pm, the bats depart in a mass exodus for feeding in the jungle, anywhere up to 50km away. It’s a spectacular show and visitors are treated to the sight of long narrow swirling black clouds streaming out of the cave entrance like smoke.
Meanwhile, the night shift moves in – thousands of small swiftlets (swallows) enter the caves, returning to their nests. It is here (and in similar caves throughout Borneo) they make their nests purely from their own salivary secretions. These valuable nests (around $1,000 per kg) are used to produce the highly regarded Chinese cuisine, bird’s nest soup.
Just 23km out of Sandakan, in Sabah, the Sepilok Nature Reserve is a huge natural jungle area housing the protected Orang-Utan Rehabilitation Centre, the Sun Bear Conservation Centre and a Rainforest Discovery Centre.
The jungle scenery is breathtaking, especially at the high orang-utan feeding platform where at 10am and 3pm daily, the rangers arrive with huge buckets of fruit, which they empty onto the decking.
The beguiling creatures swing down using vines, ropes and cables to land on the deck. They love the keeper and cuddle him as they pick over the fruit to eat. Many other smaller long-tailed macaque monkeys drop down quickly to steal a few bananas and then climb away at full speed.
Orang-utans are apes (or lovable mammals) found only in Borneo and Sumatra. They share 97 per cent of the same DNA as humans.
The Sun Bear Conservation Centre is the best place to see the endangered honey bears, the smallest in the world. They love honey, figs and termites and are expert climbers, making their nests in the treetops – anywhere up to 40m above ground. Their name stems from the remarkable markings in their chest fur.
At the Labuk Bay Proboscis Monkey Sanctuary, you’ll see groups of the most remarkable and cheeky monkeys of all. The males, with their long white tails, pendulous noses and rotund stomachs usually have a harem of around 10 females. Younger males spend their days trying to take over the harem, providing plenty of entertainment.