New Guinea Rainforest

The New Guinea rainforest covers most of the island of New Guinea, north of Australia. New Guinea is the second biggest island in the world, and most of it is still covered in dense rainforest. Many areas have never been studied by scientists, and probably millions of species are still waiting to be discovered. New Guinea is also home to over 1,000 different cultures, more than any other place on Earth.

• Areaapprox. 900,000 km²Mostly still standing
• CountriesIndonesia, Papua N.G.Island split between two
• Forest coverapprox. 70%Mostly untouched
• LanguagesOver 1,000More than any other place on Earth
• Famous birdBird of paradiseAbout 40 species, mostly here
• Strange animalTree kangarooA kangaroo that lives in trees

The New Guinea Rainforest compared

Area (million km²)

Amazon5.5

Congo2.0

Sundaland1.0

N. Guinea0.9

New Guinea has the third largest tropical rainforest after the Amazon and the Congo. The forest is mostly intact because of the rugged terrain.

What is the New Guinea Rainforest?

The island of New Guinea sits just north of Australia and is split between two countries: Indonesia (the western half, called Papua) and Papua New Guinea (the eastern half). The interior of the island is wildly mountainous, with peaks rising over 4,000 metres. The rugged terrain has made New Guinea one of the hardest places on Earth to explore, and large parts of the highlands were not even mapped until the 20th century.

Birds of paradise

The most spectacular birds in the world live here. Birds of paradise are approx. 40 species of mostly small to medium-sized birds, almost all of which evolved here. The males have evolved fantastic ornamental plumage: long curling tail feathers, brilliant iridescent shields of colour, head-feathers shaped like flags or wires. To impress females, the males perform elaborate dances, shaking, flashing and reshaping themselves into living sculptures. Charles Darwin himself struggled to fit them into his theory of natural selection until he realised they had been shaped by sexual selection, the choice of females.

Fact New Guinea has the most cultures of any place on Earth. Over 1,000 different languages are spoken on the island, about one seventh of all the world's languages. Many of those languages are spoken by only a few hundred or a few thousand people.

Strange animals

New Guinea has many animals you will not find anywhere else. Tree kangaroos are exactly what they sound like: kangaroos that have evolved to live in trees, with longer arms, shorter legs and a long tail for balance. Echidnas (spiny ant-eating mammals that lay eggs) include the long-beaked echidna, which lives only here. There are also dozens of species of marsupial including possums, cuscus, bandicoots and the dingiso (a tree kangaroo found only in the central highlands).

Threats and conservation

Most of the New Guinea rainforest is still standing, but it is increasingly under pressure from logging, palm oil plantations, mining and road building. Several large national parks protect the most important areas. Conservation is difficult because of the rugged terrain, the political situation in Indonesian Papua (where there is a long-running independence movement) and the difficulty of working with so many isolated communities.

Did you know? Some New Guinea tribes were completely cut off from the outside world until aeroplanes flew over them in the 1930s. Several tribes still avoid contact with the modern world, living deep in the forest as they have for thousands of years.

Deeper dive: Wallacea, biogeography and the Lapita migrations

New Guinea sits on the Sahul continental shelf, which during the last ice age was connected to Australia as a single landmass. This is why New Guinea's mammal fauna is dominated by marsupials and other groups (echidnas, tree kangaroos, possums) related to those of Australia, rather than the placental mammals of Asia. The boundary between the Asian and Australian biogeographical regions runs through the islands just west of New Guinea, in a region called Wallacea, named after the 19th-century naturalist Alfred Russel Wallace who first identified it.

Wallacea is a transition zone between the Asian and Australian faunas, with species mixed from both sides. The exact boundary is debated: the Wallace Line follows the deep ocean strait between Bali and Lombok and between Borneo and Sulawesi; the Lydekker Line follows the edge of the Sahul shelf east of Wallacea. The complicated geography of these islands and straits has produced extraordinary biodiversity, with many endemic species evolving on each isolated island.

The first humans reached New Guinea at least 50,000 years ago, crossing from Southeast Asia by boat. The thousand-plus languages of New Guinea today belong to many unrelated language families, the result of small communities developing independently for tens of thousands of years in the rugged highland valleys. The Trans-New Guinea language family alone contains over 400 languages. Around 1,500 BC, the Lapita people began spreading from the coast of New Guinea and the surrounding islands across the Pacific, eventually colonising thousands of remote islands as far as Hawaii, Easter Island and New Zealand, one of the great migrations of human history.

The other big Southeast Asian rainforest is on Borneo. The countries that share New Guinea are Indonesia and Papua New Guinea.