Stretching 560km from the Crocker Range in the southwest of Sabah to the Sulu Sea in the east, the Kinabatangan River sustains one of the world's richest ecosystems. Home to Borneo’s indigenous species, the orang utan and the proboscis monkey, the lower basin of the river has the largest concentration of wildlife in South-East Asia, including some endangered and endemic species. A trip up the river is the best way to catch a glimpse of some wildlife – if you’re lucky, you might even get to see an Asian elephant or a Sumatran rhinoceros wandering among the trees.