Flora & Fauna
The dominant original vegetation is the lowland diterocarp forest. However, nearly half the park, and almost all the forest below 500m. The remaining primary jungle is luxurious with many commercial timber species (dipterocarpus). The mengaris tree - notorious for its beehives - is common here. The Shorea faguetiana called pokok Seraya Siput Kuning (88.32 m) was recorded as the tallest tropical tree in the world's. Above 1,000 metres, thick damp mossy forest takes over. Orchids, epiphytes and forest herbs grow in abundance. About 150 orchid species were recorded and among the attractive collections is the Elephant-Ear Orchid (Phalaenopsis Gigantea) - largest orchid leaves in the world's.
Wildlife is abundant but animals tend to be shy and are not easily seen. There are large number of mammals varied ranging from Long Tailed Macaques and the Red Leaf Monkey. A score of tree-top inhabitants, especially the Borneon gibbons (Hylobates muelleri), the Maroon Langurs (Presbytis rubicunda) and the Grey-leaf monkeys (Presbytis hosei).
Besides mammals, Tawau Hills Park also possesses a rich comunity of other vertebrates - amphibians. Of the 8 species of Hornbills known from Sabah, 6 species are found here, namely, the Black, Bushy-crested, Helmeted, Rhinoceros, White-crowned and the Wreathed hornbills. While, 3 species of the rare pheasants occur here, namely, the Crested-fireback, the Great argus and the Malayan peacock pheasants.
Others common animals include the Forest Tortoise along the trail or the beautiful Giant Tree Squirel, Civets-cats, Leopard-Cats and even a Clouded Leopard, once, have also seen. The clear streams are occupied by a variety of small fishes and many frogs whose nightly croakings dominate the evening air.