One of the often difficult jobs faced by archaeologists is working out what’s been chewing on the finds.
Collections of animal bones in a single area, and confined to a single layer, are known as faunal assemblages. They are in many cases treasure troves of useful information, providing insight into what communities ate, how they hunted, butchered, treated bones, and disposed of remnants.
Interpreting the evidence, however, is not always straightforward, in large part because other animals – after the humans have been at work – often make a meal of what’s left.
In most parts of the world, the task of identifying marks made by the teeth and jaws of such secondary feeders (be they companion animals or visiting carrion-eaters) is relatively easy. This is because scientists have conducted experiments, giving various modern animals – dogs, coyotes, bears and raccoons, for instance – juicy bits of bone to have a go at, and then, afterwards, meticulously catalogued the indentations, punctures and scrapes made by their teeth and claws.
The result is an index of possibilities, which gives archaeologists a solid dataset to use in identifying which animals took a bite or two out of the bones in their dig-sites.
So far, so methodical. A paper published in the Journal of Archaeological Science: Reports, however, reveals that this approach, so useful in most parts of the world, fails miserably when dealing with Australian fauna.
Loukas Koungoulos and Patrick Faulkner from the University of Sydney, together with Brit Asmussen from the Queensland Museum, report setting up a series of trials to collect and collate tooth-marks from modern Australian predators so that the actions of their antecedents could be reliably identified.
To this end, they write, appetite-inducing bones were given to “captive Tasmanian devils, dingoes, tiger quolls, eastern quolls, lace monitors, dogs, and one of the authors”.
The result was a collection of 2895 tooth-marks, but the distinguishing information that could be extracted from them was, sadly, almost zero.
The only species that could be reliably identified were the lace monitor (Varanus varius), the eastern quoll (Dasyurus viverrinus) and, presumably, the author.
Marks left by the three most historically likely species to make lunch out of a pile of discarded bones – the Tasmanian devil (Sarcophilus harrisii), dingo (Canis dingo), and tiger quoll (Dasyurus maculatus) – were impossible to tell apart, even though the species are different in size to each other.
The surprising similarity, the authors suggest, is because of the strong jaws and bone-crushing habits of the devil and quoll, both of which are known as daysurids. These adaptations result in tooth-marks that are way out of proportion to their size, and equal to those left by much larger dingoes.
“Body size does not accurately predict Australian carnivore tooth-mark size,” the researchers conclude, probably to the disappointment of archaeologists across the continent.