Cool and lush, Khao Yai National Park is an easy escape into the primordial jungle. The 2168-sq-km park, part of a Unesco World Heritage site, spans five forest types, from rainforest to monsoon. The park's centrepiece is Nam Tok Haew Suwat (น้ำตกเหวสุวัต), a 25m-high cascade that puts on a thundering show in the rainy season. Nam Tok Haew Narok (น้าตกเหวนรก) is its larger cousin, with three pooling tiers and a towering 150m drop.
The park is the primary residence of, among many others, shy tigers and elephants, noisy gibbons, colourful tropical birds and countless audible, yet invisible, insects. Khao Yai is a major birding destination with large flocks of hornbills and several migrators, including the flycatcher from Europe. Caves in the park are the preferred resting place for wrinkle-lipped bats. In the grasslands, batik-printed butterflies dissect flowers with their surgical tongues.
The park has several accessible trails for independent walking, but birders or animal trackers should consider hiring a jungle guide to increase their appreciation of the environment and to spot more than the tree-swinging gibbons and blood-sucking leeches (the rainy season is the worst time for the latter). In total, there are 12 maintained trails criss-crossing the entire park; not ideal if you want to walk end to end. Access to transport is another reason why a tour might be more convenient, although Thai visitors with cars are usually happy to pick up pedestrians.
A two-hour walk from the visitor centre leads to the Nong Pak Chee Observation Tower , which is a good early morning spot for seeing insect-feeding birds, occasional thirsty elephants and sambar deer; make reservations at the visitor centre. It's important to understand that spotting the park's reclusive tigers and elephants is considered a bonus, with most people happy just to admire the frothy waterfalls that drain the peaks of Big Mountain.
