If you think a journey from Bali to Lombok feels farther than it is, join the club. Back in 1856, a British naturalist made the same observation. His name was Alfred Russel Wallace, and the biological rift between these twin neighboring isles is now known as “Wallace’s Line”.
“In this Archipelago,” Wallace wrote home, “there are two distinct faunas rigidly circumscribed, which differ as much as those of South America and Africa, and more than those of Europe and North America: yet there is nothing on the map or on the face of the islands to mark their limits.”
Wallace discovered the Bali-Lombok division—along with more than a thousand new species and a working theory of evolution—by luck. It helped, of course, that he traversed some 14,000 miles through what is now Indonesia pinning and pickling, tagging and bagging some 125,660 specimens of natural history.
Roughing it for eight years, Wallace might have been Asia’s first ecotourist. He settled comfortably into huts where we now bunk up at losmen. He hired indigenous guides, treating them with a respect nearly unheard of at the height of the British Empire. And he traveled by all means of local conveyance—cargo ships, dugout canoes, a Moluccan prahu and a treacherous but endearing Bugis schooner. The very unreliability of the transport offered him great serendipity:
“Having been unable to find a vessel to Macassar, I took passage to Lombok, where I was assured I should easily reach my destination. By this delay, which seemed at the time a misfortune, I was able to make some very interesting collections in Bali and Lombok, two islands which I should never have otherwise seen. I was thus enabled to determine the exact boundary between two of the primary zoological regions, the Oriental and the Australian.”
On Lombok, it was the cockatoos that first caught Wallace’s eye. “This is the most westerly point on the globe where any of the family are to be found,” he noted. He also spotted honey-suckers and Megapode mound-maker birds “here first met with on the traveler’s journey eastward.” Bali’s barbets, fruit-thrushes and woodpeckers, meanwhile, were nowhere to be seen. Nor were there any of the tigers or rhinos known from the western islands of the archipelago. Further years of observation led Wallace to sum up “…we shall find that all the islands from Celebes (Sulawesi) and Lombok eastward exhibit almost as close a resemblance to Australia and New Guinea as the Western Islands do to Asia.”
Indeed, there could be no stranger neighbors than Asia and Australia. As Wallace explained, “it is well known that the natural productions of Australia differ from those of Asia more than those of any of the four ancient quarters of the world differ from each other.” Wallace had no way to know how ancient these quarters were, or where they had all come from. But our modern understanding of continental drift suggests that Indonesia is in fact the reunion site of long-lost supercontinents.
It all started back in the Mesozoic era, some 150 million years ago, when Pangea, the mother of all supercontinents, split in two. Laurasia (today’s North America and Eurasia) headed north and Gondwanaland (South America, Africa, Antarctica and Australia) ventured south. Each took their own share of animals: dinosaurs, most notoriously, but also some newfangled creatures—early mammals, followed soon after by birds.
By the curtain call of the Mesozoic (65 million years ago), dinosaurs were down for the count and mammals had split into rival factions. Modern placental mammals had old-fashioned, pouch-bearing marsupials on the run. Up in Laurasia, where the placentals got their start, marsupials were squeezed out by 30 million BC, save for a few crafty possums. But down in Gondwanaland, the marsupials ruled the roost. Only a smattering of placentals had clambered aboard the drifting continent, now breaking up yet further. Placentals stood no chance in Antarctica when it froze solid 14 million years ago. And in South America the mammal wars got totally out of hand—placental sloths and armadillos grew as big as tanks to fend off pouch-bearing “wolves”, “bears” and “saber-toothed cats”. But even those marsupial beasts were doomed 3 million years ago when South America slammed back into North America and its armies of real bears, wolves and cats.
Which left Australia as last the outpost for kangaroos, koalas and other keepers of the pouch. Modern mammals never made it that far—save one or two. So today, watching this old chunk of Gondwanaland inch closer to Laurasia is like witnessing alien worlds on a collision course. Strange creatures now intermingle along the stepping stone islands of Nusa Tenggara, Sulawesi and Maluku—a mixing zone known as Wallacea.
Three curious features distinguish Wallacea:
First, you find endemics—species living on one island and nowhere else on Earth. (Sulawesi boasts 88 unique birds and 82 unique mammals.)
Second, you find mad experiments in evolution. The babirusa, a primeval pig with tusks erupting through its nose, begs the question “Why?”
Third, you find an “island effect”: a trend for animals to be oddly big or small. No where is this more famous than on Flores and Komodo islands. There, fearsome lizards the size of “dragons” inspired the film King Kong. And just thousands of years ago, Flores was prowled by dog-sized rats, cow-sized elephants and people no taller than five-year-olds. Smaller, in fact, than Tolkien’s hobbits, which inspired the nickname for a new fossil human species discovered in 2003.
Wallace, himself, might have been shocked to find that 150 years after his passage, such startling discoveries await among the islands now bearing his name. At this rate, there must be plenty more on the horizon. [END]
Wallacea: Stepping Stones Between Supercontinents, © Djuna Ivereigh, is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License. Excerpts may be reproduced with a credit to DjunaPix Indonesia Photography, linked to http://blog.djunapix.com/2010/05/wild/wallacea-supercontinents.