Animals of Papua New Guinea

Papua New Guinea is a country in Oceania that comprises the eastern half of the island of New Guinea and its offshore islands in Melanesia. The country is the world's third largest island country with an area of 462,840 km²,

Many species of birds and mammals found on New Guinea have close genetic links with corresponding species found in Australia. One notable feature in common for the two landmasses is the existence of several species of marsupial mammals, including some kangaroos and possums, which are not found elsewhere. Papua New Guinea is a megadiverse country.

Many of the other islands within PNG territory, including New Britain, New Ireland, Bougainville, the Admiralty Islands, the Trobriand Islands, and the Louisiade Archipelago, were never linked to New Guinea by land bridges. As a consequence, they have their own flora and fauna; in particular, they lack many of the land mammals and flightless birds that are common to New Guinea and Australia.

Australia and New Guinea are portions of the ancient supercontinent of Gondwana, which started to break into smaller continents in the Cretaceous period, 65–130 million years ago. Australia finally broke free from Antarctica about 45 million years ago. All the Australasian lands are home to the Antarctic flora, descended from the flora of southern Gondwana, including the coniferous podocarps and Araucaria pines, and the broad-leafed southern beech, These plant families are still present in Papua New Guinea. New Guinea is part of the humid tropics, and many Indomalayan rainforest plants spread across the narrow straits from Asia, mixing together with the old Australian and Antarctic floras. New Guinea has been identified as the world's most floristically diverse island in the world, with 13,634 known species of vascular plants.

PNG includes a number of terrestrial ecoregions:

• Admiralty Islands lowland rain forests – forested islands to the north of the mainland, home to a distinct flora.
• Central Range montane rain forests Green tropical rainforest of Papua New Guinea bears a sharp contrast to nearby arid Australia.
• Huon Peninsula montane rain forests
• Louisiade Archipelago rain forests
• New Britain-New Ireland lowland rain forests
• New Britain-New Ireland montane rain forests
• New Guinea mangroves
• Northern New Guinea lowland rain and freshwater swamp forests
• Northern New Guinea montane rain forests
• Solomon Islands rain forests
• Southeastern Papuan rain forests
• Southern New Guinea freshwater swamp forests
• Southern New Guinea lowland rain forests
• Trobriand Islands rain forests
• Trans-Fly savanna and grasslands
• Central Range sub-alpine grasslands

Three new species of mammals were discovered in the forests of Papua New Guinea by an Australian-led expedition in the early 2010s. A small wallaby, a large-eared mouse and shrew-like marsupial were discovered. The expedition was also successful in capturing photographs and video footage of some other rare animals such as the Tenkile tree kangaroo and the Weimang tree kangaroo. Nearly one quarter of Papua New Guinea's rainforests were damaged or destroyed between 1972 and 2002. Papua New Guinea had a Forest Landscape Integrity Index mean score of 8.84/10, ranking it 17th globally out of 172 countries. Mangrove swamps stretch along the coast, and in the inland it is inhabited by nipa palm, and deeper in the inland the sago palm tree inhabits areas in the valleys of larger rivers. Trees such as oaks, red cedars, pines, beeches are becoming predominantly present in the uplands above 3,300 feet. Papua New Guinea is rich in various species of reptiles, indigenous freshwater fish and birds, but it is almost devoid of large mammals.