World Heritage Identification Number: 1013
World Heritage since: 2000
Category: Natural Heritage
WHE Type: Protected Areas & National Parks
Transboundary Heritage: No
Endangered Heritage: No
Country: 🇲🇾 Malaysia
Continent: Asia
UNESCO World Region: Asia and the Pacific
Map
Gunung Mulu National Park: A Tropical Karst Haven
Nestled within the heart of Borneo, the Gunung Mulu National Park (often abbreviated as Mulu National Park) stands as a testament to the wonders of nature and the intricate beauty of tropical karst landscapes. Established in 1974 and designated as a UNESCO World Heritage Site in 2000, this pristine protected area spans an expansive 52,864 hectares, making it one of the largest national parks in Malaysia.
More to come…UNESCO Description of the World Heritage Site
Important both for its high biodiversity and for its karst features, Gunung Mulu National Park, on the island of Borneo in the State of Sarawak, is the most studied tropical karst area in the world. The 52,864-ha park contains seventeen vegetation zones, exhibiting some 3,500 species of vascular plants. Its palm species are exceptionally rich, with 109 species in twenty genera noted. The park is dominated by Gunung Mulu, a 2,377 m-high sandstone pinnacle. At least 295 km of explored caves provide a spectacular sight and are home to millions of cave swiftlets and bats. The Sarawak Chamber, 600 m by 415 m and 80 m high, is the largest known cave chamber in the world.
UNESCO Justification of the World Heritage Site
Criterion (vii): Gunung Mulu National Park is an area of exceptional natural beauty, with striking primary forest, karst terrain, mountains, waterfalls and the largest caves on earth. Sarawak Chamber, the largest cave chamber in the world, stretches 600 m in length by 415 m wide and 80 m high. With a volume of 12 million cubic meters and an unsupported roof span of 300 m, this chamber dwarfs any other large chamber so far discovered. Deer Cave at 120 to 150 m in diameter is the largest cave passage in the world known at the present time and the Clearwater Cave System holds the world record as the longest cave in Asia at 110 km of mapped and explored passages. As some of the largest caves in the world they contain fine examples of tropical river caves, flood incuts, vadose, and phreatic caves, exhibiting fine examples of all types of speleothems (structures formed in a cave by the deposition of minerals from water).
Criterion (viii): The park is an outstanding example of major changes in the earth’s history. Three major rock formations are evident; the Mulu Formation of Paleocene and Eocene shale’s, and sandstone, rising to 2,376 m at the summit of Gunung Mulu: the 1.5 km thick Melinau Limestone formation of Upper Eocene, Oligocene and Lower Miocene, rising to 1,682 m at Gunung Api; and the Miocene Setap Shale formation outcropping as a gentle line of hills to the west. Major uplift that occurred during the late Pliocene to Pleistocene is well represented in the 295 km of explored caves as a series of major cave levels. The surface and underground geomorphology and hydrology reveal significant information on the tectonic and climatic evolution of Borneo. The sequence of terrestrial alluvial deposits provides an important record of glacial – interglacial cycles with the series of uplifted caves ranging from 28 m to over 300 m above sea level are at least 2 to 3 million years old, indicating uplift rates of about 19 cm per 1,000 years.
Criterion (ix): The property provides significant scientific opportunities to study theories on the origins of cave fauna with over 200 species recorded, including many troglobitic species and it displays outstanding examples of ongoing ecological and biological processes. Seventeen vegetation zones have been identified along with their diverse associated fauna. Some 3,500 species of plants, 1,700 mosses and liverworts and over 4,000 species of fungi have been recorded within the property. There are 20,000 species of invertebrates, 81 species of mammals, 270 species of birds, 55 species of reptiles, 76 species of amphibians and 48 species of fish.
Criterion (x): The property supports one of the richest assemblages of flora to be found in any area of comparable size in the world. It is botanically-rich in species and high in endemism, including one of the richest sites in the world for palm species and contains outstanding natural habitats for in-situ conservation for a large number of species; Deer Cave alone has one of the largest colonies in the world of free tailed bats, Chaerephon plicata at over 3 million. This one cave also has the largest number of different species of bats to be found in a single cave. Several million cave swiftlets (Aerodramus sp.) have been recorded from one cave system, constituting the largest colony in the world. Many species of fauna are endemic and 41 species are included on the endangered species list.
Encyclopedia Record: Gunung Mulu National Park
The Gunung Mulu National Park, also known simply as the Mulu National Park is a national park in Miri Division, Sarawak, Malaysia. It is a UNESCO World Heritage Site that encompasses caves and karst formations in a mountainous equatorial rainforest setting. The park is famous for its caves and the expeditions that have been mounted to explore them and their surrounding rainforest, most notably the Royal Geographical Society Expedition of 1977–1978, which saw over 100 scientists in the field for 15 months. This initiated a series of over 20 expeditions now named the Mulu Caves Project.Additional Site Details
Area: 52,864 hectares
Number of Components: 1
(viii) — Outstanding example representing major earth stages
(ix) — Outstanding example representing ecological and biological processes
(x) — Contains most important habitats for biodiversity
Coordinates: 4.13333 , 114.91667
IUCN World Heritage Outlook
The 2025 Conservation Outlook on Gunung Mulu National Park reports the following assessment:
Source: International Union for Conservation of Nature (IUCN) · View assessment
Image
© Juanita at the Japanese wikpedia, CC BY-SA 3.0 Resized from original. (This derivative is under the same CC BY-SA license.)
World Heritage Research
Discover scientific research and academic studies that deepen our understanding of Gunung Mulu National Park from its history and significance to its conservation, management, and contemporary challenges.
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A new species of Leptolalax (Anura: Megophryidae) from Gunung Mulu National Park, Sarawak, East Malaysia (Borneo)
Researchers have identified a new species of frog, Leptolalax, within Gunung Mulu National Park, Sarawak, East Malaysia (Borneo). This discovery was made through morphological analysis, distinguishing the new species from previously described ones, including Leptolalax dringi and Leptolalax gracilis. The new species exhibits unique traits such as large body size, a rounded snout, bipartite subgular vocal sac in males, and a distinctive advertisement call with high-frequency modulation (7225-9190 Hz). Additionally, it lacks supraaxillary glands and ventrolateral glandular ridges, further setting it apart. The study highlights the rich biodiversity of Gunung Mulu National Park and contributes to the understanding of amphibian diversity in Borneo.
Dehling, J. M., & Matsui, M. (2025). A new species of Leptolalax (Anura: Megophryidae) from Gunung Mulu National Park, Sarawak, East Malaysia (Borneo) (Version 1766573317070) [Dataset]. MagnoliaPress via Plazi. https://doi.org/10.48580/D3K2T
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“The park is the people”: World heritage as antipolitical and neocolonial environmental governance in mulu park, Malaysia
Gunung Mulu National Park exemplifies the neocolonial and antipolitical dimensions of global conservation governance. The study reveals how the World Heritage Convention, through its technical and scientific frameworks, prioritizes nature for global enjoyment while marginalizing Indigenous voices and displacing local communities. By analyzing site selection processes in Mulu Park, Malaysia, researchers demonstrate how these practices normalize 'global' values, often facilitated by international non-governmental organizations (BINGOs), thereby perpetuating land grabs and cultural displacement without meaningful local participation.
DeLoach, H., & Trauger, A. (2026). “The park is the people”: World heritage as antipolitical and neocolonial environmental governance in mulu park, Malaysia. Environment and Planning E: Nature and Space. https://doi.org/10.1177/25148486261444551
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Parasitoids reared from a stick insect egg mass in Sarawak (Hymenoptera: Ichneumonidae and Torymidae), with a new species of Palpostilpnus and a new host association for Rhynchoticida
Researchers document new host associations for two egg parasitoid species, Palpostilpnus mulu (Ichneumonidae) and Rhynchoticida ovivora (Torymidae), both reared from a stick insect egg mass in Gunung Mulu National Park, Sarawak. The study describes P. mulu as a new species and clarifies the host of R. ovivora for the first time in Borneo. The findings provide insights into the ecological relationships between Phasmatodea (stick insects) and their hymenopteran parasitoids, while also discussing phasmid egg morphology as an adaptation against parasitism. This report contributes to the understanding of rarely documented parasitoid-host dynamics in this UNESCO-listed tropical rainforest ecosystem.
Darling, D. C., Broad, G. R., & Büscher, T. H. (2026). Parasitoids reared from a stick insect egg mass in Sarawak (Hymenoptera: Ichneumonidae and Torymidae), with a new species of Palpostilpnus and a new host association for Rhynchoticida. Journal of Natural History, 60(29-32), 1613–1626. https://doi.org/10.1080/00222933.2026.2683085
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Pervasive speleogenetic modification of cave passages by nitrification of biogenic ammonia
Research in Gunung Mulu National Park, Sarawak, reveals a previously undocumented process of cave passage modification driven by microbial nitrification of biogenic ammonia. This study demonstrates that ammonia gas released from bat and swiftlet guano is oxidized on moist cave surfaces, producing aggressive nitric acid solutions that accelerate limestone dissolution. The resulting geomorphological features overwrite original passage morphologies, challenging traditional interpretations of speleogenesis in tropical environments. Geomorphological and geochemical evidence suggests this biogenic overprint is more widespread than previously recognized, with profound implications for understanding post-speleogenetic modification and secondary cave enlargement.
Farrant, A. R., Koether, J. M., Barton, H. A., Lauritzen, S.-E., Pennos, C., Smith, A. C., White, J., McLeod, A., & Eavis, A. J. (2025). Pervasive speleogenetic modification of cave passages by nitrification of biogenic ammonia. Geomorphology, 483, 109822. https://doi.org/10.1016/j.geomorph.2025.109822
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Tropical temperature evolution across two glacial cycles derived from speleothem fluid inclusion microthermometry
A new study reveals that tropical temperatures in Northern Borneo, specifically within Gunung Mulu National Park, closely tracked Southern Hemisphere temperatures and atmospheric CO₂ concentrations over two glacial cycles. Using speleothem fluid inclusion microthermometry—a highly precise method based on the density of trapped water—the research reconstructed cave temperatures spanning 127,000 years, from 460 to 333 thousand years ago. The findings indicate that deglacial warming in this region was accompanied by relatively dry conditions, with temperature changes reaching amplitudes of up to 4.3°C between glacial and interglacial periods. Notably, the study also identifies a site-specific Antarctic amplification factor, suggesting stronger polar temperature responses compared to tropical regions.
Krüger, Y., Pasqualetto, L., Fernandez, A., Cobb, K. M., & Meckler, A. N. (2025). Tropical temperature evolution across two glacial cycles derived from speleothem fluid inclusion microthermometry. Climate of the Past, 21(9), 1553–1584. https://doi.org/10.5194/cp-21-1553-2025
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An economic assessment on public well-being for biodiversity conservation in Gunung Mulu National Park, Sarawak, Malaysia
A mean willingness to pay of MYR40.61 (USD9.60) per park entry for biodiversity conservation in Gunung Mulu National Park was identified, revealing that public support is strongly influenced by attitude and experience rather than awareness or economic factors. The study, involving 87 visitors and 99 local community members, used validated questionnaires to assess preferences and well-being, finding that socio-demographic and environmental factors significantly shaped willingness-to-pay (WTP) for conservation efforts. Notably, respondents with lower knowledge but high positive attitudes showed strong support for reduced entrance fees, while economic considerations did not predict WTP. This research highlights the complex interplay between social values, conservation awareness, and economic valuation in protected areas, offering insights to guide sustainable tourism policies.
Ibrahim, M. S. N., Johari, S., Assim, M. I. S. A., Mohammad, S. K. W., Afandi, S. H. M., & Hassan, S. (2024). An economic assessment on public well-being for biodiversity conservation in Gunung Mulu National Park, Sarawak, Malaysia. Environment, Development and Sustainability, 27(6), 14497–14521. https://doi.org/10.1007/s10668-024-04533-5
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Diurnal activity of a trawling insectivorous bat species, Myotis horsfieldii , in Gunung Mulu National Park, Malaysian Borneo
Researchers have documented extensive diurnal activity of Horsfield’s bat (Myotis horsfieldii) in Gunung Mulu National Park, Malaysian Borneo, challenging the conventional understanding that bats are predominantly nocturnal. Over six years (2015–2020), repeated observations at 14 sites revealed these bats foraging along streams and rivers during daylight hours, confirmed by bioacoustics showing feeding buzzes. This behavior persists despite the presence of diurnal avian predators like bat hawks (Macheiramphus alcinus) and competitors such as cave swiftlets (Aerodramus spp.). The findings suggest that this trawling insectivorous species may exploit daytime foraging to avoid night-time competition with other bats, potentially indicating a broader ecological strategy in the region.
Mc Arthur, E., Huang, J. C.-C., López-Baucells, A., Rocha, R., & Khan, F. A. A. (2024). Diurnal activity of a trawling insectivorous bat species, Myotis horsfieldii , in Gunung Mulu National Park, Malaysian Borneo. Journal of Natural History, 58(37-40), 1559–1573. https://doi.org/10.1080/00222933.2024.2393464
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