The term Tropical Lowland Rain Forest is used to describe the forest found in perpetually wet tropical areas where there is little or no seasonal water shortage and the climate is continuously warm and humid. In the lowland rain forest of Borneo temperatures average around 31 Celcius Degree during the day and 22.5 Celcius Degree at night. The humidity at its lowest is around 70% in the middle of the day but reaches 100% at night.

The Staghorn Fern, Playtycerium coronarium, another apiphytic fern. The reservoir of nutrients collected by the leaf bases of this fern is also sometimes exploited by other plants, such as orchids.

Large rain forest trees often have huge buttress roots at the base of their trunk. Most loeland forest soils are shallow, preventing trees from producing a deep taproot. Tree roots thus grow outwards away from the base of the trunk instead of down.

Many trees which occur in the forest understorey bear their flowers and fruits on their trunks, a phenomenon called cauliflory. Brightly coloured flowers and fruits produced low down on the trunk of these smaller trees attract many birds, small mammals and insects to act as pollinators and seed dispersers. It may be that the stillness of the air in the dense understorey restrict small trees using wind to pollinate their flowers, as their branches never reach the forest canopy where winds are present.

Often the most exciting part of the day is around dawn when the ghostly mist shrouding the forest canopy slowly lifts, evaporating in the warmth of the sun. The silence is broken by the rich whooping and gurgling calls of Borneon Gibbons ( Hylobates muelleri ) in the tree tops, proclaiming their territories.

Although gibbons are less likely to flee while calling, one should still approach a group quietly. All of Sabah's primates have very keen eyesight and often detect human presence long before you have a chance to glimpse them. Admire the grace and agility of the gibbons swinging away  through the trees after spotting you. Usually these animals do not move very far, but hide among the foliage of another tree and watch you curiously as you try again to locate them. All arboreal primates flee through the canopy to safety when disturbed.

Active from the first hours of morning, the Borneon Gibbon (  Hylobates muelleri ) forms small family groups to defend a territory of some 20-30 ha.

Some other birds calls which will definately attract your attention are the raucous cacles and noisy wing flapping of hornbills in the forest canopy high above you. All eight Bornean species occur in eastern Sabah. Each species has a distinctive call. The Rhinoceros Hornbill ( Buceros rhinoceros ) has a characteristic roaring call.

Hornbills often have large, decorative processes ( known as casque ) above their bills, which accounts for their name.

Rhinoceros Hornbill ( Buceros rhinoceros ) pauses on a tree branch high in the canopy.

The orchids ( family Orchidaceae ), which attract interest because of their pretty or unusual flowers, also include many epiphytic species. Many epiphytic orchids grow high up in the branches of tall forect trees but some prefer the darker conditions of the forest understorey or forest floor. Some orchid species are saprophytic and have no leaves, obtaining all their nutrients from the soil and decaying plant matter in the leaf litter. There are more than 1,400 species of orchid in 147 genera found in the rain forest of Borneo.

Medusa's Orchid ( Bulbophyllum medusae ), with tightly clustered flowers that bear long, flowing flowers sepals, recalling the snaky looks of the mythological Medusa's head.

Small mammals that are active by day include the treeshrews ( family Tupaiidae ). They are sometimes seen foraging for fruits and insects in low streamside vegetation. Treeshrews are often mistaken for squirrels but they are actually more closely related to primates. Five of the eight species of treeshrews occuring in Borneo are endemic to the island.

Some forest birds also frequent small streams, so if you sit quietly by one you may be lucky enough to spot some birds, such as the beautiful White-crowned Forktail ( Enicurus leschenaulti ), searching among stones for insects or flitting about restlessly near the waters's edge.

Sambar Deer ( Cervus unicolor ), the largest forest deer, is found in open areas of forest such as river banks and forest edges. These deer are more active at night, although one can occasionally br seen during the day.

The best known, and probably the most appealing of Borneo's primates, the Orang Utan ( Pongo pygmaeus ) will probably visit as they are extreamly fond of fig fruits. Although orang utans are generally solitary, unlike gibbons and other monkeys which are found in family groups, they occasionally move around with other individuals. The orang utans move slowly and deliberately around in the fig branches, looking for ripe fruit and have been seen to chase off gibbons who have to wait until the orang utans have had their fill.

Mother and baby orang utan.

Often seen flitting along the open bright river banks and sunny forest streams are many of Sabah's beautifully coloured butterflies looking for flower nectar and mineral salts. The Birdwing butterflies ( family Papilionidae ), with black markings and yellow, white, blue or green patches, may be the most striking. The Rajah Brooke's Birdwing ( Trogonoptera brookiana ) is the forest's most magnificent butterfly, with its 18-cm wingspan. The Tree Nymph butterfly ( Idea iasonia ) resembles a translucent, polka-dot bow tie, fluttering and glidding at forest edges and in sunny patches of the forest understorey.

Common Bluebottle ( Graphium sarpedon ) congregating with other butterfly on a damp stream bank. They probe their long proboscis in the sand to drink the mineral salts.

At dawn, forest and river bocome visible again as the shroud of mist begins to dissipate.

At stream and river banks, one can see substantial numbers of lianas or climbing plants. Lianas climb other plants to reach the higher light levels in the forest canopy. At river banks the higher light levels and disturbance due to the periodic flooding of the river allow lianas to proliferate, giving the forest the appearance of a leafy-blanketed jungle.
 
 
 
 
 
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