Loagan Bunut features a unique ecosystem based on Sarawak's largest natural lake (65 ha). The shallow lake usually drains completely when the water in the nearby Tinjar river is low (normally February and late May or early June/July). As the water level subsides, huge flocks of wading birds gorge themselves on fish and other aquatic creatures trapped in the mud. When the lake is dry, plants sprout from the mud and are eaten by insect larvae. When the rains come and the lake fills up, returning fish feed on the larvae, breed in the lake, and the whole cycle starts again.
Fishermen from the local Berawan tribe have developed a unique method only found at Loagan Bunut, known as Selambau. They use huge scoop nets mounted on large rafts to catch migrating fish, which are kept alive in submerged bamboo cages until they can be transported to market.
The surrounding terrain features a variety of forest types, ranging from mixed peatswamp forest with huge stilt-rooted trees at the water's edge, to towering Alam forest with a canopy height of over 60 m, and helps to make Loagan Bunut a birdwatcher's paradise. Permanent residents include eagles, swallows, malkohas, stork-billed kingfishers, magpies, robins, doves, bulbuls, racket-tailed drongos, pied hornbills and kites, while darters, egrets, herons, bitterns, storks and broadbill arrive during dry spells to feed on the trapped fish. Other animals found in the park include barking deer, bearded pigs, sambar deer, long-tail macaques, black banded langurs, lesser mouse deer, small-tooth palm civets, giant squirrels, provost squirrels, Bornean gibbons, many species of frogs and small lizards, dog-headed water snakes and a variety of tree snakes. Estuarine crocodiles are occasionally sighted.
During dry spells it is possible to stroll across the dried-up lake bed, but visitors must be accompanied by a local guide for safety reasons. More permanent trails include the Hydrology Trail (2km) which provides a close-up view of the peatswamp ecosystem. The 260m Tapang Trail showcases the towering tapang tree (Koompassia excelsia), the World
's third tallest tree, whose heavy, dense wood is claimed to be the best for making blowpipes. The Belian Trail (720m) features the belian tree (Eusideroxylon zwageri, also known as Borneo ironwood) which produces one of the world's hardest, and most valuable timbers.
Boat trips can be arranged at the Park Headquarters. Early morning is the best time to appreciate the mist-shrouded scenery, midday is best for viewing wading birds feeding on trapped fish, and late afternoon offers superb sunsets and more bird watching possibilities. The boatmen usually drive the narrow boats right into the forest, amongst huge stilted tree roots where monkeys and squirrels can often be seen. A boat trip will usually include a visit to the fascinating Selambau scoop nets, and during fish migrations visitors can watch the fishermen at work and buy freshly caught fish. The boatmen will also point out an ancient Berawan burial platform, or Klirieng, supported above the lake by sturdy belian pillars. The boats are operated by local Berawan fishermen who have a great deal of local knowledge and usually speak acceptable English. The charter rate is RM 60.00 per boat per hour for up to 4 passengers, with an additional RM 15.00 per hour for every extra passenger.