Last updated December 13, 2018 at 5:33 pm
Prehistory hunters on the Indian Ocean island of Madagascar are thought responsible for the eventual extinction of megafauna such as giant lemurs, hippos and elephant birds.
New archaeological evidence from southwest Madagascar, published in PLoS ONE, has found that the age of animal bone damage caused by modern humans indicates they colonised the island thousands of years later than previously thought.
The international team, including Flinders University palaeontologist Aaron Camens and led by Professor Atholl Anderson from the Australian National University, studied 1787 bones belonging to extinct megafauna, such as hippos, crocodiles, and giant tortoise, dated between 1900 before present (BP) and 1100 years BP.
Microscopic analyses revealed that potential cutmarks in bones dated before 1200 years BP were in fact animal biting and gnawing marks, root etching, or chop marks from the excavation, suggesting that cutmarking (and human activity) only appeared after that time point.
Several pieces of evidence, including archaeological findings such as chert tools and charcoal, provide a direct indication of human occupation in Madagascar from about 1500 years BP.
In contrast, previous studies suggested that the island’s early settlers made first landfall as early as 5000 years BP, based on indirect evidence from animal bones with damage (cutmarks) presumably resulting from human activity.
Professor Anderson and colleagues revisited these bone collections and excavated three new sites in southwest Madagascar to collect a larger sample of animal bone material.
Similar results were obtained upon re-examination of bone damage previously interpreted as cutmarks in samples from old collections.
The study also confirmed previous evidence of megafaunal extinction starting around 1200 years BP.
These findings add to the evidence showing that prehistoric human colonisation of Madagascar began between 1350 and 1100 years BP, and suggest that hunting gradually led to the extinction of the island’s megafauna.
Madagascar’s colonisation is key for tracing prehistoric human dispersal across the Indian Ocean, but exactly when human settlement began in the island remains unclear.
The authors add: “Recent estimates indicate human arrival in Madagascar as early as approximately 10,000 years ago.”
Diverse evidence – from bone damage, palaeo-ecology, genomic and linguistic history, archaeology, introduced biota and seafaring capability – indicate initial human colonisation of Madagascar was later at 1350-1100 years BP.
Results have implications for decline and extinction of megafauna, a proposed early African hunter-gatherer phase, and trans-oceanic voyaging from Southeast Asia.
The research was supported by the Australian Research Council Discovery Project Grant DP0986991.
‘New evidence of megafaunal bone damage indicates late colonization of Madagascar’ (2018) by A Anderson, G Clark, S Haberle, T Higham, M Nowak- Kemp, A Prendergast, C Radimilahy, LM Rakotozafy, Ramilisonina, JL Schwenninger, Malika Virah-Sawmy and Aaron Camens was published by PLoS One 13(10): e0204368. https://doi.org/10.1371/journal.pone.0204368