Submitted by Mythical_Atlacatl t3_11huevk in askscience

As far as I can see there is evidence of some homo sapien relatives making it to islands around indonesia/malaysia, but is there any evidence of them in Australia or was it only modern humans who made it that far?

Is it likely that other human relatives made it to Australia but have just left no evidence so far? Africa to Indonesia is a long way, makes Australia look like its right in their back yard.

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apj0731 t1_jawgap7 wrote

Hi!

No. There is loads of evidence of H. erectus and other earlier members of genus Homo making it to Indonesia and surrounding islands as you state (see: Trinil, Sangiran, H. floresiensis, etc.). However, there are no evidence of hominins other than H. sapiens found in Australia.

Keep in mind that Australia was not attached to mainland Eurasia. There were periods of time when Indonesia was accessible by foot. There is no evidence that H. erectus made boats.

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vokzhen t1_jb6n8j6 wrote

> There were periods of time when Indonesia was accessible by foot

This rough map of now-submerged river systems is what really made it "real" for me.

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apj0731 t1_jb6ovi3 wrote

That's an awesome model. Thanks for sharing!

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Any-Broccoli-3911 t1_jawgf57 wrote

No, Australia was separated from Asia during the glaciations while the parts of Indonesia homo erectus went to were contiguous to Asia.

There's no evidence homo erectus ever learned to build boats to cross to islands like Australia.

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atomfullerene t1_jawxqjk wrote

There's no evidence of this, but it's not just H. erectus that follows this pattern. There's a very clear transition of fauna between SE Asia and Australia that occurs in this region. The most famous division here is the Wallace line, which divides areas that were connected to the Asian mainland during the ice age from islands that remained separate, but early hominids actually dispersed a bit further, about to the Weber line. This is similar to elephants and some other large mammals, and implies they managed to cross short stretches of open water to reach these islands. But they apparently couldn't cross the larger gap between Timor and Australia.

It's worth noting that this dispersal happened during glacial periods when sea levels were lower and the geography of the area was quite different. You could walk all the way out to around Bali because sea levels were lower. And H. erectus and kin were all over south Asia and had been for more than a million years.

Really, it's not unusual to see that sort of spread. There's a fair amount of overlap between South Asian and African large mammals. When the Sahara is a grassland/savanna (which happens sometimes), large mammals with adaptable habits can disperse pretty easily between Africa and Asia, which is what you are seeing with hominins. But crossing the open ocean is much more difficult, and it seems that only modern humans managed it.

Here's a paper about hominins in SE Asia, which also has a map of sea levels and one of known hominin fossil sites

https://clas.uiowa.edu/sites/default/files/news-events/Larick-Ciochon-2015-Hominin%20Biogeography-ISEA-Evolutionary-Anthropology.pdf

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