Known as “Father River,” the mighty Kinabatangan springs from the mountains of southwest Sabah and races towards the Sulu Sea, east of Sandakan City – a distance of 560 kilometers.

Here thrive the oldest rainforests on earth, formed 130 million years ago. From the ground, it is a verdant vision of ferns, vines, mosses and other plants jostling for space and sunlight, the rhythmic soundtrack of insect, bird and primate calls in the background.

This is the realm of the Orang Sungai, the indigenous river people of Malaysia, a large group that speaks over 20 dialects. To the east lie the lands of the Ida’an. Kampongs (villages) are connected by water and are teeming with giant prawns, stingrays, even freshwater sharks. The setting isn’t as fantastic as Avatar’s Pandora, but it comes mighty close.

The World Wide Fund for Nature (WWF) estimates that over 250 bird, 50 mammal and 20 reptile species inhabit the Kinabatangan. Occasionally, the river might bless a lucky adventurer with a fleeting glimpse of the rare Bornean clouded leopard or the even rarer Sumatran rhinoceros. Even without binoculars, visitors can spot crocodiles, birds and up to ten types of primate, especially when the water recedes each summer.

The elephants are, of course, the stars. Borneo’s pygmy forest elephants differ from Asian elephants by being smaller, fatter and more docile. They also have straight tusks, larger ears and tails long enough to give them a cute and comical appearance. Males stand 8-feet tall and tip the scales at 3,000-kg, with slightly smaller females. About 1,500 are left, prompting some scientists to consider them the rarest of elephants. The largest remaining herds are concentrated around the lower Kinabatangan.