Mount Bosawi Crater

Mount Bosavi, Papua New Guinea
Mount Bosavi / Nyctalimon, / CC BY 2.0

Main characteristics

Coordinates: 6.6019 S 142.8434 E
No:511        (list of all attractions)
Category:Ecosystems, Volcanoes
Values:Biology, Visual
Address:Australia and Oceania, Papua New Guinea, south-western part of Southern Highlands province, extensive crater of Mount Bosavi
Area:˜ 2,000 ha

One of the most inaccessible parts of New Guinea is Mount Bosawi. This enormous mountain rises tall above the surrounding rainforest. Forests near its summit are a kind of small world by itself, with numerous species of plants and animals which are not found anywhere else in the world.

Extinct volcano

Mount Bosavi stands some 40 km apart from the Central Range - main mountain ridge of Papua New Guinea. This extinct volcano is 2,507 m high and it rises above the surroundings for 1,887 m. It has not erupted for some 250,000 years.

The summit of this volcano has collapsed long ago forming an extensive crater which is some 4 km wide and 1 km deep. Everything - surroundings of the mountain, its crater and even the steep rims of the crater are covered with a pristine rainforest.

Bosawi people

Few people live in this area. It could be different in earlier times but as white people arrived in the 20th century, local people caught new diseases and many died.

Cave in Bosavi crater, Papua New Guinea
Cave in Bosavi crater / Nyctalimon, , CC BY-SA 2.0

Nobody lives in the crater of Bosawi or its slopes. But north from the mountain there are four groups of native people (Bosavi kalu - Bosavi people) - Kaluli, Ologo, Walulu and Wisesi, all speaking in Non-Austronesian languages. First contact of Kaluli with white people took place in 1940ies. But even these people know rather little about Mount Bosavi and not too many visit it.

Unique species

As anywhere else in the world, also Mount Bosavi has altitude zonation - higher up in the mountain the climate conditions differ from the climate in lowlands and species composition near the top is different than elsewhere - it is cold and wet here. Above the 2,000 m height the trees in the forest are low, covered with epiphytes and the ground is covered with a wet carpet of moss. Diverse climatic conditions lead to high diversity of the plant and animal species: on Mount Bosavi this diversity is very high. Here live numerous birds of paradise, exotic orchids.

View across Bosavi crater, Papua New Guinea
View across Bosavi crater / Nyctalimon, , CC BY-SA 2.0

Due to the isolation from other highlands near the summit of Mount Bosavi have evolved numerous unique species which are not met anywhere else in the world. Scientists have known this for decades but very few have ever reached the mountain and many species for sure have not been discovered yet.

Wider public learned about Mount Bosavi in 2009 when an expedition was organised by BBC with an aim to rise awareness of this crater in face of danger - logging near it. During this expedition in a few days time here were discovered more than 40 new species of animals including at least 16 species of frogs, two species of lizards, at least three fish species and one bat, many hitherto unknown insects and spiders.

Some of the endemic animals here are:

  • Orchid in Bosavi crater, Papua New Guinea
    Orchid in Bosavi crater / Nyctalimon, , CC BY-SA 2.0
    Bosavi wooly rat (Mallomys spp.) - one of the biggest known rats, up to 82 cm long (including the tail) and 1.5 kg heavy. This animal has thick fur and lives at the height of around 1,000 m. It was first discovered in 1973 and then rediscovered in 2009 by the BBC expedition - animal has no fear of humans;
  • Bosavi silky cuscus - a subspecies of Phalanger sericeus;
  • Henamo Grunter (Hephaestus sp.) - amazing river fish which communicates with other fish with swim bladder which emits grunting noise;

Protection and research

Waterfalls in Bosavi crater, Papua New Guinea
Waterfalls in Bosavi crater / , Flickr, SA BY-2.0

Mount Bosavi with its surorundings is included in the Sulamesi Wildlife Management Area which was established in 2006. Papua New Guinea has applied for a UNESCO World Heritage status for a monument called Kikori River basin / Great Papuan Plateau which includes also Mount Bosavi.

Mount Bosavi is not the only one isolated mountain in this part of New Guinea. No researchers thus far have researched Mount Murray and some peaks of Keieru Range: most likely undiscovered animals live there as well.


See Mount Bosavi Crater on the map of Papua New Guinea!


  1. Kristofer M. Helgen, Lauren E. Helgen. Biodiversity and Biogeography of the Moss-Mice of New Guinea: A Taxonomic Revision of Pseudohydromys (Muridae: Murinae). Bulletin of the American Museum of Natural History 331: 230–313. 2009.

Landmarks of Papua New Guinea

Rouna Falls, Papua New Guinea
Rouna Falls / , Flickr, SA BY-2.0

One of the most exciting and mysterious lands in the world is Papua New Guinea. This country takes half of the second largest island and numerous other larger and smaller islands. Here live diverse indigenous people speaking in 820 languages who have very diverse cultural traditions.

It is possible that this country has got the most impressive caves in the world. Here are located also some of the largest sinkholes of the world, very impressive gorges, canyons and cliff walls, as well as possibly most powerful springs in the world. Papuea New Guinea contains diverse volcanos, several geyser fields.

Biological diversity of Papua New Guinea is very high and there are locations which contain large amount of endemic species of plants and animals. Here live the largest butterflies in the world. There are exciting legends and reported sightings of cryptids - mysterious animals.


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Mist in Dendrosenecio kilimanjari woodland, Tanzania / Brendon, / CC BY 2.0

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