Nature & Wildlife

Indonesia is located on the Pacific Ring of Fire — the most tectonically active belt on Earth. Three tectonic plates (Eurasian, Indo-Australian, and Pacific) converge here, generating geological energy that has literally shaped the archipelago.

The numbers: 127 active volcanoes — more than any other country in the world. Of these, 76 are considered historically active (at least one eruption since 1600). Java alone has 45 active volcanoes on an area the size of Greece.

Famous Volcanoes

• Krakatau (1883): The explosion was the loudest sound in recorded history — audible in Australia (4,800 km away). The tsunamis killed over 36,000 people. The "Son of Krakatau" (Anak Krakatau) is actively growing today in the Sunda Strait.
• Tambora (1815): The largest volcanic eruption in recorded history — ten times more powerful than Krakatau. The ash cloud caused the "Year Without a Summer" in 1816 in Europe and North America (crop failures, famines).
• Toba (74,000 BC): The most massive eruption of the last 2 million years — left Lake Toba and a volcanic winter that nearly wiped out humanity.
• Merapi (Java): The most active volcano in Java, erupts every 4–6 years. Only 28 km from Yogyakarta — in 2010, over 350 people died.

An invisible line runs through Indonesia — between Bali and Lombok, between Borneo and Sulawesi — dividing the wildlife of the archipelago into two fundamentally different worlds. The Wallace Line, named after the British naturalist Alfred Russel Wallace, marks the boundary between the Asian and Australian fauna.

West of the line (Sumatra, Java, Borneo, Bali) live Asian animals: tigers, elephants, orangutans, rhinos. East (Sulawesi, Flores, Moluccas, Papua) are Australian relatives: tree kangaroos, birds of paradise, and the Komodo dragon — a relic from when Australia was closer to Southeast Asia.

The explanation: During the ice ages, when sea levels were 120 meters lower, Sumatra, Java, and Borneo were connected to the Asian mainland by land bridges. East of the Wallace Line, the ocean was always deep enough to act as a barrier. The animals couldn't swim across — and so completely different ecosystems developed on both sides.

For travelers, this means: When you travel from Java to Flores, you cross one of the most important biogeographical boundaries on Earth — even if you don't see it.

Indonesia is home to some of the most fascinating and endangered animal species on Earth:

Komodo Dragons

The largest lizards in the world (up to 3 meters, 70+ kg) live exclusively on Komodo, Rinca, Gili Motang, and Flores. Estimated population: 3,000 animals. → Chap. Komodo & Flores

Orangutans

Two species: The Sumatran orangutan (~14,000 animals, critically endangered) and the newly described Tapanuli orangutan in 2017 (~800 animals — the most endangered great ape species on Earth). → Chap. Sumatra

Sumatran Tigers

The smallest surviving tiger subspecies (~400 animals in the wild). Sightings are extremely rare, but tracks and signs can be found in Kerinci-Seblat and Gunung-Leuser National Parks.

Coral Triangle

Indonesia is at the heart of the Coral Triangle — the most biodiverse marine area on Earth. 600 coral species (75% of all known worldwide), 3,000+ fish species, six of seven sea turtle species, dugongs, blue whales, and the largest manta ray population in the world.

Birds of Paradise

In Papua and the surrounding islands, over 30 bird of paradise species live — birds with the most extravagant courtship dances and plumage in the entire animal kingdom. You might also spot the Red Bird of Paradise in Raja Ampat if you're lucky.