Papua New Guinea 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
New Guinea British colonial administrators each attempted to suppress the still-widespread practices of inter-village warfare and headhunting within their respective territories. In 1905, the British government transferred some administrative responsibility over southeast New Guinea to Australia (which renamed the area "Territory of Papua"); and, in 1906, transferred all remaining responsibility to Australia. During World War I, Australian forces seized German New Guinea, which in 1920 became the Territory of New Guinea, to be administered by Australia under a League of Nations mandate. The territories under Australian administration became collectively known as The Territories of Papua and New Guinea (until February 1942). Before