Island hopping

4 minute read

This article from The Age lays out an ambitious excavation schedule for Mike Morwood and colleagues:

Professor Morwood, with a team headed by Indonesian archaeological professor Fachroel Aziz from Indonesia's Geological Survey Institute, will soon start excavations in the Atambua Basin of Timor. Afterwards, the team will begin diggings in Sulawesi and will return to the Ling [sic] Bua cave in Flores, where the hobbit species was uncovered.
"We predict a number of these islands are probably going to have their own endemic human species, and many of them will be small," Professor Morwood, from the University of Wollongong, said.

The article spends some words on size differences in island animals, raises the issue of island gigantism (hmm...does this mean we'll see the return of Meganthropus?), and this:

Professor Morwood flagged that any new human species found on Timor and Sulawesi would be called Homo timoriensis and Homo celebesiensis (Celebes being the former name of Sulawesi).

That just seems like a missed opportunity. If it were me, I would sell the naming rights to the highest corporate bidder. How about "Homo pizzahutiana". Ooh ooh! "Pan crusti!" You could probably get money for at least 20 field seasons out of them.

How sustainable was "seafaring"?

I've already heard from some correspondents (many thanks!) who consider it hubristic to predict the finding of more human species in Wallacea, when the case for one is still in doubt.

Maybe so. I think that Sulawesi and Timor, in addition to other islands including Sumba and Sumbawa, may provide an important test. The reason? Seafaring.

I haven't seen anyone comment on the seafaring issue much since the Liang Bua remains were reported. Recall that when Lower to Middle Pleistocene stone tools were originally found on Flores (from the Soa Basin), their principal importance was documenting some kind of water-crossing technology in early Homo before 800,000 years ago. That was news — with no such evidence anywhere else in the world — and was subject to some controversy.

Just how good did the "seafaring" technology have to be to establish an occupation on Flores? There were at least two water crossings (Lombok and Sape Straits) of more than 10 kilometers. Robert Bednarik has conducted a series of experiments (the First Mariners Project) attempting to assess the technological requirements for such crossings.

If the seagoing technology that allowed crossings of these straits was maintained for a long time, it surely should bolster our opinion of the cultural capabilities of the hominids. A raft -- even a simple raft made out of bamboo -- is a complicated compound tool; a tool that involves many pieces put together in a series of steps. Even though many of the steps may be completely identical to each other (that is, lash logs together, repeat), still a raft requires joining dozens of different elements on a single plan, in pursuit of a single non-immediate goal. The creation of such an object would have required a sustained, goal-oriented and design-directed cognition.

Last year, I wrote:

[W]hat happened on Timor? It seems to me that the game is over if humans were on Timor in the Middle Pleistocene. There is some indication that they were. If Homo erectus could manage sea crossings to that extent further east than Flores, then there is no way that Flores was a single, unique colonization. With an occupied Timor, we have to assume that regular contacts between Flores and mainland Asia were probable.

Much depends on what the people were doing with watercraft -- were they using them for fishing? River crossings? Short island-hopping? Ecologies that encourage the use of watercraft exist in the region today, for all of these reasons and more. We can infer that if people were capable of exploiting these ecologies in the past, then the opportunity to do so would have been recurrently (or constantly) present during the last 800,000 years. Like any cultural tradition, seagoing rafts might have been lost over time. But even if people forgot how to make watercraft, the fact that they could invent them in the first place suggests that they should have invented them repeatedly. Humans certainly have done so recently.

The paradox is that regular crossings of the straits would have prevented isolation of the island populations. It would seem that the hypothesis of isolation entails that seagoing technology was not a sustainable development, and that the initial occupation of Flores (and by extension, Lombok and Sumbawa) was a matter of chance. If this is true, then early evidence of water crossings itself has little, if any, import to our interpretation of early human cognitive evolution.

Consider that other than this evidence for crossing the Lombok and Sape Straits, there is no evidence for compound tools of any kind before the Middle Paleolithic-Middle Stone Age. If Lower Pleistocene humans were capable of making a raft, this would be a major addition to the evidence for their technological competence.

Well, I don't know the answer, but I think that finding hominids on Timor would pretty much end the story in favor of more capable seafaring rather than less.

Sulawesi is less certain; it may have been too easy to get there by chance to really establish that water crossings were controlled and sustained. Sulawesi seems like a great prospect for hominid occupation; the fauna is more Asian than Flores, so it must have been comparatively easier to make the crossing. The Makassar Strait probably was not narrower than the corresponding water crossings from Bali to Lombok and Sumbawa to Komodo, but the opposing coastlines of Sunda and Sulawesi were very long, perhaps providing a greater chance of making a successful crossing without being washed clear of landfall. Of course, that makes isolation much less likely also.

The more regular water crossings were, the less likely isolation on Flores would have been. It's certainly important to look for hominids on those islands, but maybe not for the reasons everyone seems to be assuming.