The fauna in Flores varies from the Komodo dragons, to wild boars and deer, to Manta Rays swimming in the Coral Triangle. And the Wallace Line, which scientifically delineates species, is an altogether different aspect of this region.

The relatively dry and rocky Lesser Sunda’s are not home to impressive rainforests or a big diversity in strange local animals. In fact, these islands are kind of low populated with big animals. Areas which are covered in shrubs are the habitat of deer, wild pigs, bats, snakes, dragons and other lizards.

Underwater Wonderland

It’s a totally different view of the underwater world. The coral reefs there (known as the Coral Triangle) belong to the richest ecosystems in the world. Nowhere else can you find a more diverse variety of aquatic species. One single big reef in Nusa Tenggara can contain about 1000 species of fish, more than in all seas in Europe combined. The underwater world is very colorful. Brave anemone fish defend their living house against the teasing hand of the diver. Groups of coral butterflyfish float between the reef walls and other fish cross the reef in couples. The area houses big sea mammals like the sperm whale and the Indian sea cow, which looks like a walrus without teeth. Along the border of the reefs you can find big pelagic fish: peaceful whale and reef sharks, and manta’s, which are relatives of the ray fish.

The Komodo Dragon

The most impressive animal of Nusa Tenggara is the Komodo Dragon (Varanus komodoensis), the biggest living lizard in the world, which belongs to Komodo, Rinca and Western Flores. This robust animal can reach 3 meters in length and weigh up to 150 kg. The heavyweight was only known in the Western world by the start of the 20th century, mainly because Komodo then became inhabited. Shortly thereafter, stories about dangerous, seven-meter long crocodiles started to emerge. The stories were somewhat exaggerated, however these lizards can certainly scare people. The giant lizard has a physique that looks like a snake. Its jaws can move independently from each other, so it can swallow an entire prey larger than its mouth. And its forked tongue is used for smelling as well as for tasting.

Indeed, the Komodo Dragon is one of the best-equipped predators: it has a powerful tail to take down its prey, and strong jaws with sharp teeth to tear the victim apart. But its saliva and stomach juices are what kills its prey, and ultimately decay horns, bones and hair.

Wallace Line

Zoologist Alfred Russell Wallace, who toured Indonesia from 1854 until 1862, was the first to remark that the size of big land animals changed drastically when crossing the sea lane from Bali to Lombok. From Lombok, there were no elephants, rhinos or tigers anymore; in fact he didn’t see any meat-eating mammals excepting one species of a cat, nor any insect eaters.

Wallace remarked that when he went more to the east, he found lesser Asian species and more Australian species. He concluded that the border between the two groups, the two small islands – Bali and Lombok – were as big as the differences between South America and Africa, or between North America and Europe. Still, nothing on the map indicated a barrier as large as the Atlantic Ocean.

Back in London, Wallace reported his findings to the National Geographic Society in 1863. There, he drew a straight red line on the map of the Malay archipelago, with Borneo and Bali on one side, and Lombok and Sulawesi on the other. This line was later named the ‘Wallace Line’.

The zoologist was convinced that there was an actual barrier. On the peak of the last Ice Age, the sea level dropped 180 meters, so it would have been possible to walk from Singapore to Bali, but no further to the east.  The deep Lombok Strait formed an impassable barrier.

During many decades scientists conducted studies that supported Wallace’s theory, but there were also some studies that did not. Among zoologists, the ‘Wallace Line’ was mainly supported. But among botanists it was not accepted, as significant regional differences in the Indonesian archipelago (boasting about 2300 species of flora) could not be found.

Most modern biologists agree that the separation between the animals has to do with differences in habitat as well as the sea barrier. Asian fauna lives best in the western part of the archipelago because of the big precipitation and tropical forests, a habitat which is also found in Southeast Asia. The fauna in the east is adapted to dry landscapes, which are also found in Australia.

Wallace’s theory of impassable sea lanes has nearly been discarded, because the area shows a transit between Asian and Australian fauna. In the beginning, other biologists drew their own lines between other islands, but nowadays most talk about a transitional zone, instead of a strict line. However, to honor the first bio-geographer in the world, this zone – a subregion of the Oriental zoogeographical region – is still named “Wallacea” for the 19th centruy zoologist’s seminal work.