Coexistence of Humans and Megafauna in Australia

In 1830 Mr. Rankin tied a rope around a projection out of a rock face in order to lower himself into Wellington Cave (Horton, 1980). The projection turned out to be the bone of a giant extinct marsupial. It was to be the first discovery of a great range of giant marsupials. Were these animals extinct? Horton (1980), describes how Leichhardt believed that on his journeys to northern Australia he would find Diprotodon still roaming over the land. We now know that he was probably only about 20,000 years too late (Flood, 1995).

In general, all the animals greater than 40 kg in body weight became extinct at the end of the last Ice Age. By the mid 19th century scientists had already begun to postulate about the disappearance of these animals, and today it remains one of the most controversial subjects presented to man, (Horton, 1980).

Australia was not the only country to experience the extinction of large animals, (Martin, 1984). At the end of the last glacial period, nearly every continent experienced the extinction of large animals. Animals like the Mammoth, giant ground sloths, and mastodons were roaming the Americas. Northern Eurasia featured woolly mammoths, giant deer, hippopotamus, and straight-tusked elephants. Of all the continents, it could be argued that Australia lost some of the most distinctly unique fauna in the world.

The popular opinion for the cause of extinction is the ‘blitzkrieg’ hypothesis, which is held by such researches as Paul Martin in his controversial article “Prehistoric Overkill: The Global Model”. This states that humans are directly responsible for these extinctions worldwide. The Problem with this model for Australia is that humans may have arrived on this continent well before the extinctions took place (Flood, 1995). On other continents, the extinctions coincided almost exactly with the arrival of a man (Martin, 1984).

European man was not the first member of the genus Homo to set foot on the Australian continent. There is evidence to suggest that Aboriginal people have been walking on Australian soil for many tens of thousands of years (Flood, 1995). Whether or not Aboriginal people interacted with the large now extinct beasts is hard to determine. Did an overlap in time exist between humans and these large beasts? Is there any evidence that humans actively hunted them, and if they did, is it possible that they drove them to extinction?

During the late Pleistocene, the last glacial period spanning roughly 100,000 years, the faunas were completely different from those that are represented today. The most pronounced difference is body size. The term ‘megafauna’, meaning ‘large animals’ has been used to describe late Pleistocene animals throughout the world. We know that most species of mammals greater than 60 kg in body weight became extinct at the end of the Pleistocene.

‘Megafauna’ is not a taxonomic group nor is there a standard definition. Generally, the term megafauna describes an animal that weighs 40 kg or more, but in Australia that would result in including four species of living kangaroos (the grey, red, antilopine, and wallaroo) and probably excluding the extinct carnivore Thylacoleo and the smaller Sthenurus (short-faced kangaroo) (Murray, 1991 in Vickers-Rich et al., 1991). Horton, (1984) came up with a tedious but more precise definition for the Australian megafauna: ‘Animals that became extinct before the Holocene and are large, either in an absolute sense or relative to other members of some taxonomic rank, or are part of a taxonomic category all of whose members became extinct and some of whose members are large.’

Fifteen genera and roughly forty-one species of mammalian megafauna became extinct in Australia at the end of the Pleistocene (Flannery, 1990). It should be noted that this essay is not going to consider the many large birds (e.g. Genyornis) and reptiles (e.g. Megalania Prisca) which also became extinct during the Late Pleistocene. If these non-mammals are added to the tally of extinctions, the number of megafaunal genera extinct goes up to nineteen (Flood, 1990).

A typical mammalian megafaunal community consisted of a variety of forms, such as Zaglossus; Marsupial Lion Thylacoleo; giant wombats Phascolonus; long-beaked echidnas; the Marsupial Tapir (Palorchestidae); Diprotodon (Diprotodontidae); and some especially large morphs of the living Macropus (Macropodidae), (Murray, 1991 in Vickers-Rich et al., 1991). The most deserving of the term ‘megafauna’, was Diprotodon, which probably looked like a wombat ‘gone wrong’. Weighing in at 2000 kg, Diprotodon was a browser that preferred the drier open expanses of the interior of Australia.

The majority of the megafauna was herbivorous, such as the cow-sized Zygomaturus trilobus, the stumpy giant wombat Phascolonus gigas, and the large macropods Procoptodon, and Protemnodon. A trend was seen in the megafaunal assemblage, that still exists with the extant fauna today, is the distinct lack of carnivores (Flood, 1990).

The Pleistocene carnivores were limited to just three species: Thylacoleo Carnifex, known as the ‘Marsupial lion’ or the ‘giant killer possum’; the carnivorous lizard Megalania; and the Tasmanian ‘tiger’, Thylacines. Thus, the large herbivores of Australia did not co-evolve with a fleet of carnivores, like hyenas and canids and felids of Africa. Flannery, (1994) believes it is the lack of carnivores that led to faunas dominated by lumbering beasts that weren’t fast long-distance runners like those found in Africa. Flannery also suggested that being slow and naive to predators, was a factor that led to their demise.

One of the most frustrating aspects of paleontology is trying to place a fossil-bearing rock into the geological record. It wasn’t until 1945 when radiocarbon dating was first applied in Australia, that the pieces of the megafaunal puzzle started to fit together (Horton, 1980). Since then, dating techniques have improved. However, there are still problems with dating bone so paleontologists have had to rely on stratigraphic association using more reliable, datable materials such as charcoal and shell (Flood, 1990). Bone samples lose their collagen with time, and are also susceptible to contamination, especially by younger calcium carbonate carried down by groundwater. It is for these reasons that the exact timing of the extinction of the megafauna is controversial.

There are many Late Pleistocene fossil sites found within Australia (Fig Martin last of the aus meg). Of these sites, there a few that have narrowed down the timing of the extinction event somewhere around 20,000 years ago. (Fig Flood page 183). These sites, in general, are all open sites situated in south-eastern Australia (Flannery, 1990).

Gilespie et al. (1978) describe a bone bed that contains up to ‘10,000 giant marsupials’ at Lancefield Swamp in Victoria. The megafauna has been dated fairly reliably, from charcoal in sediments directly below the fossil bed, at 25,000 ± 800 BP, and 26,000 ± 650 (Fig flood). There are other, less reliable data, which may nevertheless support late existing Pleistocene megafauna. Amongst these: Spring Creek, first dated on plant matter at 19,000 ± 390 BP (Flannery and Gott 1985), later revised to 35,000 BP (Flood, 1994); Beginners Luck Cave, dated from bone collagen dates at 10,100 ± 200 BP, and 1,450 ± 210 BP (Murray and Goede, 1977, in Flannery 1990); and finally Lime Springs, NSW bone fragments have been dated at around 19,000 to 6000 BP (Flannery, 1990).

If we take these dates as correct then we could have had megafauna roaming around Australia as early as 6,000 BP or even 1,450 BP. Unfortunately, these are thought of as suspect. The bone from Beginners Luck Cave has been interpreted as being an example of contamination, and the bone from Lime Springs is thought of by some as being reworked.

The good news is that after all the controversy surrounding the dates of various sites, Cuddie Springs in semi-arid New South Wales has provided sound information about the timing of extinction. Cuddie Springs provides a secure stratigraphic succession that contains abundant bones (Fig. Cuddie springs). A series of dates have been done on charcoal that ranges from 30,280 ± 450 BP for the base of the succession to 19,270 ± 320 BP for the top. This means that Megafauna definitely existed in Australia until 20,000 years ago.

Much of the field of human paleontology is of little relevance to understanding the history of Australia evolution (Flannery, 1994). This is because much of the evolution of man occurred on other continents such as Africa and Asia. Until this year, it was known from archaeological evidence in the Northern Territory that Aboriginal people first arrived in Australia at least 60,000 years before the present (Flood, 1994).

Recent evidence suggests that we may have to re-write the textbooks when it comes to human evolution. In mid-September of this year scientists discovered in the Kimberly region of Western Australia, several enormous sculptured boulders that had detailed circular engravings on them, (Woodford, 1996). This rock art, which has been dated at up to 75,000 years old, maybe the oldest rock art in the world – more than twice the age of the French rock paintings at Chauvet and Cosquer. While excavating the sediments below the art, ochre was found dating up to 116,000 years, (Fig Sydney Morning Herald). Artifacts (stone tools) were also found in a layer of sediment between 116,000 and 176,000 years old.

During the Pleistocene, there were two major drops in sea level due to huge amounts of water frozen in ice sheets. These glacial maximums occurred around 18,000 years ago, and 140,00 years ago (Flannery, 1994). This drop-in sea level resulted in much of the Australian continental shelf becoming dry land. This made it possible to walk between Australia and New Guinea, and between Victoria and Tasmania. Flood, (1995), describes how there was probably only a 90 km gap of open ocean between Australia and Asia when the sea level was low. It is thought that this enabled the first Australian’s to ‘island hop’ their way through Asia to the north-west of Western Australia.

Regardless of the actual colonization date, it is believed that Aboriginal people occupied most of Australia by 35,000 (at least all favorable environments) (Flood, 1995). Therefore, Aboriginal people would have of the environment in which they lived with the megafauna. The exact nature of the co-existence between aboriginal people and the megafauna is still controversial.

I find it hard to believe, being someone who has come into contact with mankind, that the first Australian’s would pass up on the opportunity that the megafauna presented. The megafauna would appear to have provided the Aborigines with an excellent source of food. Flannery, (1994) states that when Charles Darwin visited the Galapagos Islands in 1835, he noticed the relative tameness of the animals there, and proposed that it due to the isolation of the islands.

Australia has had quite a unique history in that it as been physically isolated from the rest of the world’s landmasses for over 40 million years. This long period of isolation has given rise to unique flora and fauna, that was largely derived from the ancient supercontinent Gondwana. Flannery suggests that the absence of significant carnivores in Australia, together with its long isolation, evolved fauna that we’re naive to predators, let alone highly skilled hunter-gatherers. It was this naivety of the animals that contributed to their extinction. These statements are problematic due to the lack of evidence to support them.

Much effort has been made in the search of evidence to support humans hunting megafauna. This effort has only produced associations between humans and megafauna (e.g. human artifacts and megafaunal bone). It should be noted that these associations do not prove that megafauna were actively hunted, only that they co-exist in the same environments. There are Aboriginal legends that describe how they hunted “giant kangaroos” (Flood, 1995).

Flood also describes how in the Northern Territory artwork has been found that many believe depict Diprotodon. At Lake Menindee, NSW, bones of both extinct and modern species have been found along with fireplaces and ‘Kartan-type’ stone tools (‘Kartan’ is named after the large tool industry that was found on Kangaroo Island, SA) (Tindale, 1955). More recently, Liverpool plains in north-eastern NSW has produced three sites which claimed to have humans associated with megafauna (Flood, 1995).

Lime Springs, is the only site of the three in which the findings have been published. Lime Springs revealed many burnt bones belonging to Procoptodon, Diprotodon, Macropus titan, Protemnodon, and Sthenurus, clearly associated with stone tools and campfires in a stratigraphic succession. The sediments at Lime Springs have been dated at 6,000 but as explained above they have been interpreted as being reworked.

Flood, believes that what probably transpired was that a group of Aboriginal people camped on top of a sediment layer containing megafaunal bones, the bones were burnt by their cooking fires, then everything was subsequently blown into the swamp. There are other sites that show clear associations between megafauna and humans such as incisions and charring of bones at Mammoth Cave, WA, (Archer et al., 1980); and aboriginal middens and megafaunal bones at Lake Tandou Lunette western NSW, (Hope et al., 1983).

What scientists needed was direct evidence of slaughtering of the megafauna. On other continents, this problem was easily solved by the presence of abundant kill sites (Martin, 1984). In Australia, we have not as yet discovered major kill sites. At a megafaunal site in south-western Victoria, Spring Creek many bones have been found with cut marks on at least 3.8% of all the postcranial elements (Vanderwal and Fullagar, 1989).

Most of the marks are thought to have been a result of Thylacoleo carnifex gnawing on the bones. In 1984, a Diprotodon tooth was found at the site that had twenty-eight grooves notched into the surface of it. It is almost certain that these grooves are man-made. It would be very difficult to believe that Thylacoleo would have made such perfect grooves in the tooth, and there is also the question of why an animal would chew on a tooth in the first place. Vanderwal and Fullagar suggest that that the engravings on the tooth might be “tally marks for an ephemeral activity, or perhaps doodles while passing away time”.

The only direct evidence that suggests that Aboriginal people actively hunted megafauna comes from semi-arid NSW, at the Cuddie Springs site (previously mentioned). Researches have found stone tools within the succession with blood and hair on them, which was positively identified to belong to Macropus titan and Diprotodon (Flood, 1995). This was done by extracting DNA from bones of extinct species and then matching their ‘fingerprint’ with that of the blood residues on the stone tools. Flood points out that this work is as yet unpublished. Nevertheless, it indicates that Aboriginal people were at least scavenging the carcasses of the dead megafauna.

The extinction of the megafauna is a subject that I believe will remain controversial for years to come. Many theories have been proposed that have a high degree of validity, but in general, there are two schools of thought when it comes to megafaunal extinction. Those that believe it was climate-induced, and those that believe that it was Anthropocentric (Flannery, 1994). Unfortunately, this essay has not focused on the climatic model. If it had, maybe my conclusions would be different. The essence of the model is that Pleistocene megafaunal extinctions were a direct result of a dramatic world-wide climate change (Horton, 1990).

The environment changed too fast for the animals to cope with and hence they died out. Several weaknesses with the climatic model have been noted. The majority of the megafauna in Australia has managed to survive 16 out of the last 17 major glaciations (Flannery, 1995); Pleistocene extinctions occurred at different times and at different intensities in different landmasses; There hasn’t been a good explanation as to why so many of the larger taxa became extinct and so few of the smaller taxa (Flood, 1994).

Aboriginal people coexisted with megafauna in Australia for at least 30,000 years. They lived in the same environments at the same time, evident by the bones from both groups that have been found together in sediments. The way in which the megafauna and humans interacted is still uncertain. There is growing evidence, such as blood on stone tools and an engraved Diprotodon tooth, that suggests that humans actively predated on the megafauna.

An Extinction Scenario: Humans first arrived in Australia gradually spreading around the continent using fire and hunting. The megafauna was relatively slow-moving and naive to predators. The megafauna that survived the initial impact of human hunters, finally died at the end of the Pleistocene when Australia was undergoing the driest period it had.

References

1. Archer, M., Crawford, I.M. and Merrilees, D., 1980 ‘Incisions, breakages and charring, probably man-made, in fossil bones from Mammoth Cave, Western Australia’. Alcheringa, vol. 4(1-2), pp. 115-31.
2. Flannery, T. F., and Gott, B., 1985. The Spring Creek locality: a late Pleistocene megafaunal site from southwestern Victoria. Australian Zoology, vol. 21, pp. 385-422.
3. Flannery, T.F., 1990. Pleistocene faunal loss: implications of the aftershock for Australia’s past and future. Archaeology in Oceania. vol. 25, pp. 45-67.
4. Flannery, T.F., 1994. ‘The Future Eaters’ Reed Books, Port Melbourne, Victoria.
5. Flood, J., 1995. ‘Archaeology of the Dreamtime.’ Angus and Robertson, Sydney.
6. Gillespie, R., Horton, D. Ladd, P., Macumber, P., Rich, T., Thorne, A., and Wright R., 1978. ‘Lancefield Swamp and the extinction of the Australian megafauna’. Science. vol. 200, pp, 1044-1048.
7. Hope, J., Dare-Edwards, A. and McIntyre, M.L., 1983, ‘Middens and Megafauna: stratigraphy and dating of Lake Tandou Lunette, Western New South Wales’, Archaeology in Oceania, vol. 18, pp. 38-45.
8. Horton D.R., 1984. ‘Red kangaroo: last of the Australian megafauna’, in Martin P.S. and Klein R.G., op. cit., pp. 639-90.
9. Horton, D.G., 1980. ‘A Review of the Extinction Question: Man, Climate and Megafauna’. Archaeol. Phys. Anthropol. Oceania. vol. 15, 86-97.
10. Martain P.S., 1984, ‘Prehistoric overkill; the global model’, in Quaternary Extinctions. A Prehistoric Revolution (eds Martain P.S. and Klein R.G.). Tucson, University of Arizona Press, pp. 354-403.
11. Murray, P., 1991 ‘Pleistocene Megafauna of Australia.’ in ‘Vertebrate Palaeontology of Australiasia’ eds. Vickers-Rich, P. Monaghan, J.M., Baird R.F., and Rich, T.H., 1991. Pioneer Design Studio Pty Ltd. Victoria.
12. Tindale, N.B., 1955, ‘Archaeological site at Lake Menindee, New South Wales’. Records of the S.A. Museum, vol. 11, pp. 269-98.
13. Vanderwal, R., Fullagar, R.,1989. Engraved Diprotodon tooth from the Spring Creek locality, Victoria. Archaeol. Oceania. vol. 24, pp. 13-16.
14. Woodford, J. 21st September 1996. ‘Art find rewrites history’. The Age.
15. Wright, R. 1986, ‘New light on the extinction of the Australian megafauna’. Proceedings of the Linnaean Society of New South Wales, vol. 109, 1986, pp. 1-9.