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Recycle alert: This was in the print version of my Alternate History Newsletter in October 2003, but I don't think I've ever posted it on-line. If I did, I can't find it. I'm posting it now because this thread on early civilization in New Guinea made me realize I had apparently never put it online.

Elephants In Australia

What actually happened: Elephants and their extinct relatives are/were excellent swimmers, and have managed to get to several islands apparently by swimming or being washed across a few miles or a few tens of miles of ocean. If they survive on an island they tend to develop into dwarf forms. Some of the dwarf elephants on the Mediterranean islands were as small as donkeys. Now-extinct relatives of the elephants called Stegodons made it as far as the island of Sulawesa and developed a pygmy species there. There is no firm evidence that elephants or any of the extinct related species made it to Australia or New Guinea, though a few fossil finds seem to point to that possibility.

What might have happened: Let’s say that some time between one and two million years ago, Stegodons make it across the water gap from Sulawesa or one of the nearby islands to New Guinea in large enough numbers to establish a viable population. New Guinea and Australia were connected by a land bridge several times during the ice ages, so once they were in New Guinea, the Stegodons would presumably expand into Australia and even Tasmania.

Elephants and their relatives have been very successful over the last few tens of millions of years competing in just about every climate in the very tough neighborhoods of Asia, Africa, and even North and South America. They find competing in Australia comparatively easy. They quickly replace some, but not all of the big marsupial herbivores. A number of species of Diprotodonts become extinct hundreds of thousands of years before they otherwise would have. A few Diprotodont species find ways of adapting to the new competition as do most of the kangaroo species.

A successful species in a new habitat often undergoes an ‘adaptive radiation’—with new forms developing to exploit opportunities in that new habitat. Stegodons do that to some extent in Australia and New Guinea. By sixty thousand years BP there are small Stegodon species adapted to the swamps and mountains of New Guinea, somewhat larger species in the forests of eastern and western Australia, and even species adapted to Australia’s central deserts. There are even stegodons no larger than a small horse and adapted to moving relatively quickly (for an elephant) across Australia’s grasslands. Some of the smaller species have bodies shaped more like a llama than an elephant, though they still have the short neck and trunk of their elephant-like ancestors.

Stegodons also reach some of the islands around Australia/New Guinea like New Britain and New Ireland and develop bizarre small forms on those islands. Little island varieties keep developing on the islands closer to Australia and New Guinea as the ebb and flow of the ice ages raise and lower sea levels and repeatedly attach and isolate those islands to the mainland.


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