Wallace's Line
The invisible border between the wildlife of Asia and Australasia
What is Wallace's Line?
Wallace's Line is the boundary the naturalist Alfred Russel Wallace drew across the islands of Southeast Asia, after noticing that the animals changed sharply from one island to the next. It runs between Bali and Lombok, then north through the strait between Borneo and Sulawesi.
West of it live Asian animals: orangutans, wild cats, hornbills, squirrels. East of it you find cockatoos, cuscuses and honeyeaters and, further east, kangaroos and birds-of-paradise.
Why there? The islands west of the line stand on the same shallow shelf as mainland Asia, and were joined to it by land when the sea was lower. The channels along the line are deep and stayed open water, so most land animals never crossed.
What our data shows
Animal groups in the 16 parks on our site closest to the line (11 west, 5 east), with the species on each side of the line and the park where each one is easiest to see.
17 🦍 Apes & Old World Monkeys 2
West · Asia · 17 species
Show all 17
East · Australasia · 2 species
15 🦚 Peafowl & Pheasants 3
West · Asia · 15 species
Show all 15
East · Australasia · 3 species
10 🐍 Vipers 2
West · Asia · 10 species
East · Australasia · 2 species
8 🦚 Quetzals & Trogons 0
West · Asia · 8 species
East · Australasia · 0 species
None east of the line in these parks
9 🦜 Hornbills 3
West · Asia · 9 species
0 🦜 Cockatoos 6
West · Asia · 0 species
None west of the line in these parks
East · Australasia · 6 species
3 🦎 Monitor Lizards 14
West · Asia · 3 species
East · Australasia · 14 species
Show all 14
2 🐍 Boas & Pythons 13
West · Asia · 2 species
East · Australasia · 13 species
Show all 13
4 🐦 Parrots 18
West · Asia · 4 species
East · Australasia · 18 species
Show all 18
1 🐦 Honeyeaters 27
West · Asia · 1 species
East · Australasia · 27 species
Show all 27
The islands in between
Sulawesi and the islands between Bali and New Guinea, often called Wallacea, mix both worlds. At Tangkoko, on Sulawesi, the same forest holds the Knobbed Hornbill, the Celebes Crested Macaque and Gursky's Spectral Tarsier, from Asian families, and the Sulawesi Bear Cuscus, a marsupial from the Australasian side.
At Komodo, over 90% of wildlife watchers meet a Komodo Dragon on a given day, and the same islands hold the Yellow-crested Cockatoo, from an Australasian family, and the Crab-eating Macaque, an Asian monkey.
