Karremarter Carnivores

Karremarter is a small limestone shelter on the western edge of Discovery Bay. Set high on a ridge overlooking the coastal flats that surround the Piccaninnie Ponds sinkholes, it was occupied by humans during the Mid-Holocene. Relevant radiocarbon dates are 7,155-6,030 cal BP and 4,088-3,614 cal BP. One of a number of similar sized rock shelters in the area, it is only a few hundred metres from Narcurrer Shelter, and shares many of the same range of bones from human prey species.

"Debris started to accumulate in these small shelters once the sea level reached its present position and wetland and littoral resources were brought into close proximity". Sites like Karremarter and Narcurrer "were infrequently and opportunistically occupied ... brief stopping-over places for people moving along the coast or from the coast to the forested hinterland."

15 vertebrate species were identified at Karremarter, much mauled. "The taxa present, together with the degree of bone fragmentation and distribution of tooth marks, indicates that the two marsupial carnivores whose bones are found in the assemblage, the Tasmanian devil Sarcophilus harrisii, and tiger cat Dasyurus maculatus, contributed to the accumulation of all the small- and some of the medium-sized taxa present. However, humans were responsible for all the larger and some of the medium sized mammals, including grey kangaroo, wombat, swamp wallaby, pademelon and brushtail possum, an inference supported by the taxonomic distribution of calcined bone and the representation of body parts and elemental portions."

Karremarter obviously served as temporary accommodation for a number of carnivores as well as homo sapiens. Humans cooked their meat and left inedible bones. Devils and Qolls tore their meat raw and crushed their bones. The only contemporary meat eater missing from this 'den' was the Tasmanian Tiger Thylacinus cynocephalus. 

Thylacines were a mid-range or mesopredator, of between 14 and 21 kgs. They generally targeted prey considerably smaller than themselves (1-5 kgs), but may have been capable of tackling larger herbivores in favourable circumstances. Tasmanian Tigers were not as tough as they looked. Their toothy 'gape' was a threat-display, a defensive response, not necessarily signalling immediate attack.

A major limiting factor, in an evolutionary sense, was its restriction to eating vertebrate flesh. As a hyper-carnivore, it consumed only soft tissue from its kills. Not only were thylacines constrained by the size and type of prey they could seize, but also by the proportion of that animal they could effectively consume.

No such delicacy inhibited Tasmanian Devils. Specialised osteophages or 'bone-crunchers', they ingested the whole carcase. Fur, guts, bones, teeth and decay, were no match for the dentition and digestion of devils. Their short, broad skull generated an extremely high bite-force, they possessed very robust teeth, and they were able to eat up to 40% of their own body weight within half an hour.

The main disadvantage for an obligate or full-time scavenger is the unpredictability of carrion. They are dependant on another predator to secure the meal. A decrease in predator success, particularly a co-evolved 'partner' like thylacine, can lead to scavenger decline. Reliance on an inefficient and failing carnivore, neither fast nor bold, probably resulted in joint population decline, and eventual mainland extinction.

McEachern's Death Trap Cave is a natural pitfall cave near the Glenelg River. It is accessed via two by 2 metre wide sinkholes at the surface and 15 metre vertical freefalls to the cavern floor below. Excavation recovered remains of numerous species, both extinct and extant. The fossil deposit layer was radiocarbon dated 7,680 +/- 160 YBP and 5,700 +/- 110 YBP. Within this sediment, remains of both Tasmanian Devil and Tiger Quoll were found.

A few hundred metres away is McEachern's Cave, which was investigated 3 decades earlier but undated. The equivalent "Black sand layer" in this cave contained skeletal material from a similarly broad suite of animals, including devil, quoll, and the elusive thylacine. The three marsupial carnivores seem to have all been still present in this part of the coastal region during the Mid-Holocene.

FosSahul database records many dated specimens of thylacine from the Naracoorte Caves but these are from before the human era in Australia. The geographically closest remains, commensurate with Aboriginal activity, were found at Devon Downs and Fromms Landing on the Lower Murray River in South Australia. These are also the most relevant possible ages for the extinction of Devil and Tiger on the continent.

 

           Tasmanian Tiger                            Tasmanian Devil

           2,980; 3,460; 3,880 YBP               3,240; 3,756 YBP

           1,930 YBP                                     1,090; 1,930 YBP

The Spotted-Tail or Tiger Quoll was not affected by the same environmental pressures, or not to the same degree, as its bigger relatives. Dasyurus maculatus was an altogether wilier, active hunter. It fed on fast and slow moving prey and of various sizes up to 3 times its own body weight.

Hunting mostly at night, it had good vision, a strong sense of smell, and short forelimbs adapted for climbing. It travelled widely and could cope with temporary fluctuations in prey abundance. The quoll's small size and adventurousness served it well and it did not become endangered on the mainland until after European settlement and the introduction of feral cats and the red fox.

The three marsupial carnivores were rivals of humans in the quest to get high protein food. They all endured the variations of climate after the Mid-Holocene "optimum" (ca. 6,000 YBP) but not all survived the experience. When Karremarter Cave was visited by Aborigines, devils and quolls were also occasional residents, and thylacine was not too far away. The success of humans and quolls and the comparative decline of thylacine and devils probably had a few causes, but competition between predators is strongly suggested.

                                                                                                                                                      

REFERENCES:

David Frankel & Nicola Stern, 2011, 'Karreamarter - Mid to Late Holocene Stone Artefact Production and Use in the Lower Southeast of South Australia', Technical Reports of the Australian Museum, Online, 23, 59-71

Attard, Chamoli, Ferrara, Rogers, Wroe, 2011, 'Skull mechanics and implications for feeding behaviour in a large marsupial carnivore guild: the thylacine, Tasmanian devil and spotted-tailed quoll', Journal of Zoology, 285, 292-300

CN Johnson & S Wroe, 2003, 'Causes of extinction of vertebrates during the Holocene of mainland Australia: arrival of the dingo or human impact?' The Holocene, 13.6, 292-300

Rovinsky, Evans, Martin, Adams, 2020, 'Did the thylacine violate the costs of carnivory? Body mass and sexual diphormism of an iconic Australian marsupial', Proceedings of the Royal Society B, 287, 1-8

Fillios, Crowther, Letric, 2012, 'The impact of the dingo on the thylacine in Holocene Australia', World Archaeology, 44.1, 118-134

Oliver Brown, 2006, 'Tasmanian devil (Sarcophilus harrisii) extinction on the Australian mainland in the mid-Holocene: multicausality and ENSO intensification', Alcheringa Special Issue 1, 1-8

Andrew Kos, 2003, 'Re-burial taphonomic characterisation of a vertebrate assemblage from a pitfall cave fossil deposit in Southeastern Australia', Journal of Archaeological Science, 30, 769-779

Williams, Ulm, Turney, Ronde, White, 2015, 'Holocene Demographic Changes and the Emergence of Complex Societies in Prehistoric Australia', PLoS ONE, 10.6, 1-11