The islands span an area of some . The strait from Cape York to New Guinea has a width of approximately at its narrowest point; the islands lie scattered in between, extending some from furthest east to furthest west. The total land area of the islands comprises . of land are used for agricultural purposes. The
Torres Strait itself was previously part of a
land bridge known as the Arafura Plain which connected the present-day Australian continent with New Guinea (in a single landmass called
Sahul,
Meganesia,
Australia-New Guinea). This land bridge was most recently submerged by
rising sea levels at the end of the
last ice-age glaciation approximately 12,000 years ago, forming the Strait which now connects the
Arafura and
Coral seas. Many of the western Torres Strait Islands are the remaining peaks of this land bridge which were not completely submerged when the ocean levels rose. The islands and their surrounding waters and reefs provide a highly diverse set of land and marine
ecosystems, with niches for many rare or unique species.
Saltwater crocodiles inhabit the islands along with neighbouring areas of
Queensland and
Papua New Guinea. Marine animals of the islands include
dugongs (an
endangered species of
sea mammal widely found throughout the Indian Ocean and tropical Western Pacific, including Papua-New Guinean and Australian waters), as well as
green,
ridley,
hawksbill and
flatback sea turtles. The Torres Strait Islands may be grouped into five distinct clusters, which exhibit differences of
geology and formation as well as location. The Torres Strait provides a habitat for
numerous birds, including the
Torresian imperial-pigeon, which is seen as the iconic national emblem to the islanders. These islands are also a distinct physiographic section of the larger
Cape York Platform province, which in turn is part of the larger
East Australian Cordillera physiographic region.
Top Western islands (Gudaw Maluligal Nation) The islands in this cluster lie very close to the southwestern coastline of New Guinea (the closest is less than offshore).
Saibai (one of the largest of the Torres Strait Islands) and
Boigu (one of the
Talbot Islands) are low-lying islands which were formed by deposition of
sediments and mud from New Guinean rivers into the Strait accumulating on decayed coral platforms. Vegetation on these islands mainly consists of
mangrove swamps, and they are prone to flooding. The other main island in this group,
Dauan (Mt Cornwallis), is a smaller island with steep hills, composed largely of
granite. This island actually represents the northernmost extent of the
Great Dividing Range, the extensive series of
mountain ranges which runs along almost the entire eastern coastline of Australia. This peak became an island as the ocean levels rose at the end of the last ice age. The isolated and uninhabited
Deliverance Island is west of Boigu, the nearest of the Top Western islands.
Near Western islands (Maluligal Nation) The islands in this cluster lie south of the Strait's midway point, and are also largely high granite hills with mounds of
basaltic outcrops, formed from old peaks of the now submerged land bridge.
Moa (Banks Island) is the second-largest in the Torres Strait, and
Badu (Mulgrave Island) is slightly smaller and fringed with extensive mangrove swamps. Other smaller islands include
Mabuiag, Pulu and further to the east Naghir (correct form
Nagi, aka Mount Ernest Island). Culturally this was the most complex part of Torres Strait, containing three of the four groupings/dialects of the Western-central Islanders, Nagi being culturally/linguistically a Central Island (Kulkalaig territory, specifically part of Waraber tribal waters), Moa is part of the Muwalaig-Italaig-Kaiwalaig [Kauraraig/Kaurareg] tribal areas, with two groups, the Italaig of the south, and the Muwalaig of the north. Many Kauraraig also live there, having been forcibly moved there in 1922–1923. Badu and Mabuiag are the
Maluigal Deep Sea People.
Inner islands (Kaiwalagal Kawrareg Aboriginal Nation) These islands, also known as the Thursday Island group, lie closest to Cape York Peninsula, and their
topography and geological history is very similar.
Muralag (Prince of Wales Island) is the largest of the Strait's islands, and forms the centre of this closely grouped cluster. The much smaller Waiben
Thursday Island is the region's administrative centre and most heavily populated. Several of these islands have permanent freshwater springs, and some were also mined for
gold in the late 19th and early 20th centuries. Because of their proximity to the Australian mainland, they have also been centres of
pearling and
fishing industries. Nurupai
Horn Island holds the region's airport, and as a result is something of an
entrepôt with inhabitants drawn from many other communities.
Kiriri (Hammond Island) is the other permanently settled island of this group; Tuined (Possession Island) is noted for
Lt. James Cook's landing there in 1770. Moa in the Near Western group is culturally and linguistically speaking part of this group.
Central islands (Kulkalgal Nation) This cluster is more widely distributed in the middle of Torres Strait, consisting of many small sandy
cays surrounded by
coral reefs, similar to those found in the nearby
Great Barrier Reef. The more northerly islands in this group however, such as
Gerbar (Two Brothers) and
Iama (Yam Island), are high basaltic outcrops, not cays. Nagi is a culturo-linguistic part of this group, and also has high basaltic outcropping. The low-lying inhabited coral cays, such as
Poruma (Coconut Island),
Warraber Island and
Masig (Yorke Island) are mostly less than long, and no wider than . Several have had problems with
saltwater intrusion.
Eastern islands (Kemer Kemer Meriam Nation) The islands of this group (principally
Mer (Murray Island), Dauar and Waier, with
Erub Island and
Stephen Island (Ugar) further north) are formed differently from the rest. They are
volcanic in origin, the peaks of volcanoes which were active in
Pleistocene times. Consequently, their hillsides have rich and fertile red volcanic soils, and are thickly vegetated. The easternmost of these are less than from the northern extension of the Great Barrier Reef. == Administration ==