For all the proxy evidence that modern humans had reached Indonesia tens of thousands of years ago, there’s been little direct evidence because the conditions are inimical to preservation. Stone tools are forever and, under favorable conditions, rock art at least 45,500 years old has been found on the island of Sulawesi. But few actual human fossils have been found.
Now scientists report in PLOS One on finding fragments of a small but otherwise anatomically modern human who lived 24,800 to 16,000 years ago, the time of the Last Glacial Maximum, at the site called Leang Bulu Bettue on Sulawesi. The report is by Prof. Adam Brumm of Australia’s Griffith University with an international team of colleagues.
The inland limestone cave is presently 20 kilometers (12 miles) from the sea, though the average sea level was about 130 meters lower than it is now. The archaeologists dubbed the Stone Age person Maros-LBB-1a.
They didn’t find much: part of Maros’ palate, though in fragments, and a bit of right jawbone with three badly worn molars. Maros is the oldest modern human found in Sulawesi and the wider Wallacean archipelago to date
The archaeologists deduced that the remains are from a modern human, not one of the pre-modern hominins that thronged Southeast Asia, which included at the very least Homo erectus, Denisovans (a presence deduced by genetic analysis: their remains have not been found) and, on the island of Flores, the enigmatic, pint-sized species Homo floresiensis. (And never forget the enigmatic, pint-sized Homo luzonensis on the island of Luzon in the Philippines – they aren’t relevant to this story but don’t forget them anyway.)
Finding human remains on the Indonesian islands dating to the late Pleistocene is wonderful, but not a shock. Anatomically modern humans are believed to have reached the region sometime between 70,000 to 50,000 years ago.
The thing that took the archaeologists somewhat aback is the state of Maros’ teeth. They were in terrible condition.
Small even by Stone Age standards
Leang Bulu Bettue is a decently large cave, about 30 meters in depth with a 30-meter-long rock shelter along the base of the overhanging cliff. Archaeologists have found evidence of human occupation in two phases: Neolithic to modern – about 1,700 years ago until the year 1790, and Stone Age occupation from about 50,000 to 16,000 years ago.
The oh-so-rare ancient human remains were found in the cave in 2017, and were the only such find in that layer, the “richest” in the cave system vis-à-vis the cultural assemblage.
The palate and bit of jaw were found in proximity with “profuse remains of what we consider to be ‘domestic’ activities,” the team writes – including the litter of tool-making and burned bones from meals. We will get to the meals.
As for the palate and teeth, the archaeologists concluded that these had belonged to one individual, and apparently an elderly one at that. Maros may not have been ritually interred: the researchers found no evidence suggesting burial in the layer, though note that they’re not done excavating the layer and may yet find burials.
And what do Maros’ teeth tell us? First of all, they’re rather small, though within the spectrum of modern folk. Petiteness seems to have been quite the local human trend.
Sulawesi is part of Indonesia and, geographically, of Wallacea – a biogeographically distinct zone consisting of roughly 2,000 oceanic islands between the continental shelf of Southeast Asia and Australia. None of the Wallacean islands were ever connected to the continents, even when the ocean was at its lowest during the Ice Age.
Before Maros, the oldest anatomically modern humans found in Wallacea were three relatively complete bodies dating to 17,000 to 12,000 years ago, in rock shelters of Tron Bon Lei on the small island of Alor.
These Tron Bon folk were small-statured, unique even by Pleistocene standards in the combination of small and narrow morphologies, according to the paper about them. Their actual height remains to be elucidated because there, too, their remains were badly degraded. But the people of Tron Bon were clearly wee.
But it isn’t that Maros’ teeth just fell out with age, as happens; in that case we would expect to see direct evidence such as bone growth over the empty tooth sockets, Brumm explains. Maros’ teeth had lost the bulkiest part of the crown and not merely from gnashing.
Dine on swine and arboreal marsupials
As said, the team found only the three molars that had become worn down almost to the root.
Maros may have had more teeth in life and they could have become scattered through some postmortem mishap. But the archaeologists note that none were found, and the state of the socket surfaces where the canine and incisors should have been suggests they fell out before death.
Secondly, all the tooth sites show lesions of what the archaeologists believe was periodontal disease (inflammation of the gums and bone supporting the teeth).
Dental hygiene in the Stone Age was likely a spotty affair, but compared with other human remains found elsewhere from comparable times – such as the Grotte des Pigeons in Morocco – Maros had lost a lot of teeth.
“All round, this ancient individual suffered from very poor dental hygiene,” Brumm remarks. The condition of Maros’ teeth was relatively worse than that of other hunter-gatherers, for whatever reason: “It’s at the bad end of the spectrum but some hunter-gatherer groups with a high carbohydrate/sugar diet also had bad teeth,” he adds.
(One adds that completely separate research discovered that as had been expected, the transition from hunting and gathering to farming did result in more cavities, presumably because we ate more carbs – but it didn’t necessarily make us sicklier as some had assumed.)
Maros’ problem may not have been dental caries per se. The archaeologists did discern pinhole-sized cavities, but comparison with the teeth of hunter-gatherers from Gua Cha in Malaysia, and the evidence, suggests the problem may have been gum disease. Caused by what?
In Morocco 15,000 years ago, hunter-gatherers ate a lot of carb-rich nuts, which played havoc with their teeth. Their teeth were as bad as today’s kids on candy.
In Maros’ case, aside from using them to eat, he – or she – seems to have also used his teeth as a tool, possibly dragging palm fronds along the molar surface to produce twine.
This hypothesis is based on the “unusual” dental wear signs. Making cord, twine or rope isn’t in and of itself surprising in the least; we know Neanderthals could make string, based on finds in France. Modern people presumably could too, even if they used their teeth in the process.
Or maybe like the prehistoric Moroccans, Maros just doted on fructose, carbs and nuts. “I don’t think the tooth loss and the use of the teeth as tools are directly correlated, although the latter certainly contributed to the considerable amount of attrition and wear observable on two of the teeth (the first and third molars),” Brumm says. Maros’ tooth loss was probably due to oral disease, which brings us to what this person was eating.
Freshwater snails harvested from inland rivers, estuaries and swamps, Brumm says – the denizens of Bulu Bettue ate a lot of those. They ate copiously of the bear kuskus, which aren’t bears but bug-eyed arboreal marsupials.
There was also lots of pig on the menu, principally the warty pig, which had been celebrated in the world’s earliest known figurative painting, also done on Sulawesi at least 45,500 years ago. Apparently swine appreciation goes back a very long time.
There is no direct evidence that the people in Leang Bulu Bettue ate shellfish, or giant rats, Brumm clarifies, though other peoples in the region definitely dined on these. In fact, giant rats remain on the menu most everywhere there are giant rats. You can find recipes for stewed or roast giant rat on YouTube. Enjoy.
Sulawesi had been graced with an array of insular megafauna that are now extinct, including the elephant species Stegodon (both dwarfed and undwarfed variants), other proboscideans and a largish pig called Celebochoerus. There is, Brumm notes, no evidence that modern humans encountered any of these animals, which may have gone extinct before our species arrived. Yes, they could have been wiped out by other hominins; their fate is not clear. The only large animals remaining on Sulawesi are anoas, and two types of pig: the babirusa and warty pig.
As for the soul, the area is studded with hundreds of caves and rock shelters, some with spectacularly ancient art attesting to occupation by modern humans (there is no sign, yet at least, that other hominins created figurative art).
At Bulu Bettue, the archaeologists found two stones with engravings that may represent figurative motifs as well as ancient hand stencils done in red, over which later people drew dancing humans and other figures drawn using charcoal. Those dancers are much later, from the Late Holocene.
It cannot be known if Maros descended from the prehistoric people who drew the pig and other art in deep prehistory. In the same archaeological layer as Maros, in previously reported work researchers discovered what they call portable art (meaning engraved rocks small enough to carry around).
Enter the Denisovans, again and again
Sadly, the sparse human remains in Bulu Bettue cannot shed light on the various models for the peopling of Wallacea and the region. “It is unfortunate that the first part of an ice age human we have found in Sulawesi happens to be a small and relatively undiagnostic portion of an upper jaw, with just three teeth preserved,” Brumm observes. “Such is life – and archaeology.”
Basically everything we know about human evolution has changed in the last decade or so, based on new fossil discoveries and mainly following the development of techniques to sequence ancient DNA – though it bears stressing that one cannot extract, let alone utilize, DNA from just any fossil bone; the conditions have to be right.
In this case, the researchers haven’t even tried to extract genetic material from Maros’ palate or teeth, yet at least, but their expectations are not high.
“Given the antiquity, and the fact it was recovered in the humid tropics, it is very unlikely ancient DNA will still be preserved in this specimen,” Brumm says.
Among the astonishing things recently deduced when one can extract DNA, the authors note that today’s Papuans were discovered to be carrying genes from two completely separate Denisovan lineages that separated over 350,000 years ago. Moreover, one of these introgressions was very recent, it seems, happening in Wallacea and persisting until nearly the end of the Pleistocene. Eastern Asians, meanwhile, have traces of yet a third Denisovan lineage.
This argues, as archaeologists put it, for considerable complexity in “archaic contact,” with modern humans interbreeding with multiple groups of Denisovans that were geographically isolated from each other over deep evolutionary time.
So what are we to learn from all this? To brush our teeth properly and floss too, never mind the haters. And not to use our teeth to make rope.