The impressive peak of Gunung Mulu, which at 2376 m is the second highest mountain in Sarawak, is the centrepiece of the eponymous 529-sq km national park. The luscious jungle, home to orchids and hornbills, also boasts the largest limestone cave system on the planet. Mulu is basically a huge hollow mountain range, covered in 180-million-year-old rainforest. Its primary jungle contains an astonishing biological diversity. The park was awarded UNESCO World Heritage status in 2000.
In 1974, three years after Mulu was gazetted as a national park, the first of a succession of joint expeditions led by the British Royal Geographical Society (RGS) and the Sarawak government began to make the discoveries that put Mulu on the map. In 1980 a cave passage over 50 km long was surveyed for the first time. Since then, a further 137 km of passages have been discovered. Altogether 27 major caves have now been found speleologists believe they may represent a tiny fraction of what is actually there. The world’s biggest cave, the Sarawak Chamber, was not discovered until 1984.
In the 1960s and 1970s, botanical expeditions were beginning to shed more light on the Mulu area’s flora and fauna: 100 new plant species were discovered between 1960 and 1973 alone. Mulu Park encompasses an area of diverse altitudes and soil types – it includes all the forest types found in Borneo except mangrove. About 20,000 animal species have been recorded in Mulu Park, as well as 3500 plant species and 8000 varieties of fungi (more than 100 of these are endemic to the Mulu area). Mulu’s ecological statistics are astounding: it is home to 1500 species of flowering plant, 170 species of orchid and 109 varieties of palm. More than 280 butterfly species have been recorded. Within the park boundaries, 262 species of bird (including all eight varieties of hornbill), 67 mammalian species, 50 species of reptile and 75 amphibian species have been recorded.
Mulu’s caves contain an unusual array of flora and fauna too. There are three species of swiftlet, 12 species of bat and nine species of fish, including the cave flying fish and blind catfish. Cave scorpions – which are poisonous but not deadly – are not uncommon. Other subterranean species include albino crabs, huntsman spiders, cave crickets, centipedes and snakes (which dine on swiftlets and bats). These creatures have been described as “living fossils... [which are] isolated survivors of ancient groups long since disappeared from Southeast Asia.”