The Nusa Tenggara (lit. Southeast Islands), or Lesser Sunda Islands, are a group of islands in the middle-south part of Maritime Southeast Asia. Together with the Greater Sunda Islands to the west they make up the Sunda Islands. The islands are part of a volcanic arc, the Sunda Arc, formed by subduction along the Java Trench.

Geology
The Lesser Sunda Islands consist of two geologically distinct archipelagos.The northern archipelago, which includies Bali, Lombok, Sumbawa, Flores and Wetar, is volcanic in origin. It began to be formed during the Pliocene, about 15 million years ago, as a result of the collision between the Australian and the Asian plates.The islands of the southern archipelago, including Sumba, Timor and Babar, are non-volcanic and appear to belong to the Australian plate.The geology and ecology of the northern archipelago share a similar history, characteristics and processes with the southern Maluku Islands, which continue the same island arc to the east.

There is a long history of geological study of these regions since Indonesian colonial times; however, the geological formation and progression is not fully understood, and theories of the geological evolution of the islands changed extensively during the last decades of the 20th century.

Lying at the collision of two tectonic plates, the Lesser Sunda Islands comprise some of the most geologically complex and active regions in the world.Biodiversity and distribution is affected by various tectonic activities. The islands of the northern archipelago are geologically young being from 1 to 15 million years old, and have never been attached to a larger land mass.

Ecology
The Lesser Sunda Islands differ from the large islands of Java or Sumatra containing many small islands as well as deep oceanic trenches. Flora and fauna immigration between islands is restricted, leading to the evolution of a high rate of localized species.The Wallace Line passes through the islands between Bali and Lombok, along the deep waters of the Lombok Strait which formed a water barrier even when lower sea levels linked the now-separated islands and landmasses on either side. Alfred Wallace’s famous book, The Malay Archipelago was the first significant recording of this natural history, and remains one of the most important sources on Indonesian natural history.

While many ecological problems affect both small islands and large landmasses, small islands suffer their particular problems and are highly exposed to external forces. Development pressures on small islands are increasing, although their effects are not always anticipated. Although Indonesia is richly endowed with natural resources, the resources of the small islands of Nusa Tenggara are limited and specialised; furthermore human resources in particular are limited.

General observations about small islands that can be applied to Nusa Tenggara include:

* a higher proportion of the landmass will be affected by volcanic activity, earthquakes, landslips, and cyclone damage;
* Climates are more likely to be maritime influenced;
* Catchment areas are smaller and degree of erosion higher;
* A higher proportion of the landmass is made up of coastal areas;
* A higher degree of environmental specialisation, including a higher proportion of endemic species in an overall depauperate community;
* Societies may retain a strong sense of culture having developed in relative isolation;
* Small island populations are more likely to be affected by economic migration.

Fauna
The island is famous not only for its heritage of convicts but also for the unique fauna which roam it. The Komodo dragon, the world’s largest living lizard, takes its name from the island. A type of monitor lizard, it inhabits Komodo and some of the smaller surrounding islands, attracting many tourists. Komodo can growing to an average length of 2 to 3 metres (6.6 to 9.8 ft) and weighing around 70 kilograms (150 lb). Their unusual size is attributed to island gigantism, since there are no other carnivorous animals to fill the niche on the islands where they live, and also to the Komodo dragon’s low metabolic rate.As a result of their size, these lizards dominate the ecosystems in which they live.Although Komodo dragons eat mostly carrion, they will also hunt and ambush prey including invertebrates, birds, and mammals.

Mating begins between May and August, and the eggs are laid in September. About twenty eggs are deposited in abandoned megapode nests and incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take around three to five years to mature, and may live as long as fifty years. They are among the rare vertebrates capable of parthenogenesis, in which females may lay viable eggs if males are absent.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild their range has contracted due to human activities and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.