Microfauna in Drakaina Cave

Microfauna in Drakaina Cave

Small sized vertebrates, like rodents, insectivores, hedgehogs, bats, small amphibians, small reptiles and small birds comprise a complex called microfauna, the analysis of which can be very informative about the environment, the climate and the vegetation around a prehistoric archaeological site, either cave or extended settlement (Brothwell and Jones 1978). Even though such small sized animals have no economic or sentimental value for humans, they are used as key indicators for vegetation, humidity, places with swamps or running water. Since each one of them nests in different microhabitats, an alpine vole is not expected to be found in an olive grove or a vine yard neither a frog is expected in a typically dry area (Ondrias 1966; Arnold and Burton 1992; Mitchell-Jones 1999). A microfaunal assemblage can help in recreating the original ecosystem of an area, since agricultural, pastoral or building activities as well as the various geological phenomena tend to reform the landscape (Stahl 1996).

Apodemus sp.

Microfauna can be retrieved from geological (rock fissures, lacustrine deposits, cave sediments) and archaeological deposits (dwellings, refuse pits, wells, caves used by humans) (Andrews 1990). Humans are very rarely responsible for the deposition of archaeological microfauna, since the latter is of no economic or emotional value to them. Common depositional factors include wind or water activity, soil erosion processes and predation by avian or mammalian carnivores in caves or isolated places (taphonomy) (Andrews 1990). Birds such as owls or kestrels and mammals such as weasels or foxes eat their small prey and then either regurgitate or produce within their scats a pellet, containing bones, fur and feathers. The bones that go within the digestive track of a predator can bear signs on their surface, which are detected under the microscope (Andrews 1990). Furthermore, the taphonomic processes that created a microfaunal assemblage can be incorporated in the stratigraphy of a site and show how each context was created.

Crocidura sp.

Microfauna bones in Drakaina Cave are retrieved from soil samples via water flotation. The sampling strategy is the same as for the archaeobotany of the site, since the latter was first in use. Microfauna analysis will try to answer three questions: 1) the range of species that lived around the Cave during its use and how their identification helps towards a palaeoclimatic reconstruction, 2) the taphonomic processes that are responsible for the bone deposition and how they can be incorporated in the geological stratigraphy of Drakaina, 3) the conclusions that are drawn concerning human-rodent coexistence during the Cave use and how it contributes to the interpretation of the Cave use. Microfauna analysis is pursued by the use of a stereomicroscope, a digital camera attached to it and a skeletal reference collection of small sized vertebrates. The writer accomplices the analysis using the equipment in the Wiener Laboratory, at the American School of Classical Studies, and the reference collections of small vertebrates in the Seckenberg Natural History Museum in Frankfurt, Germany, and Naturalis Natural History Museum in Leiden, the Netherlands.

Sorex sp.

Identified species and their archaeological interpretation

The identified range of species includes the following rodents: Mus musculus (house mouse), Apodemus sp. (wood mouse), Glis glis (fat or edible dormouse), Rattus rattus (black rat), and insectivores: Crocidura sp. (shrew), Sorex sp. (shrew), Erinaceus concolor (σκαντζόχοιρος, hedgehog). Furthermore, some bones from small lizards have been recovered (Lacertidae indet.), but they do not outnumber the micromammal bones. All the species excluding the house mouse and the black rat reflect the natural environment around the Cave: deciduous woodland and/or maquis vegetation, like today, in the Gorge of Poros, and low altitude. The house mouse and the black rat are typical commensals around places of human action. So the house mouse reflects commensal presence and household activities in the Cave, whereas the same cannot be stated for the black rat, as only one molar belonging to it has been recovered.

Glis glis

The taphonomy of the Drakaina microfauna is very interesting, since the Cave was sporadically used by humans (Stratouli 2007), but it was (and still is) open for visits by avian or mammalian predators, who need a quiet place to roost or digest their prey and maybe spend the night. Such predatory activity is considered to have happened during the intervals of human use. So, some postcranial bones have been recovered that bear the surface modification attributed to the digestion track of a mammalian predator (fox or jackal), which belong to a horizon dated at the Late Neolithic/Early Chalcolithic and probably do not coincide with human use. The taphonomy of Drakaina microfauna is not attributed to humans at all; apart from the predation activity, the taphonomy of the bones is considered to be entirely due to natural processes, mainly the death of the small creatures.

Mus musculus

Conclusively, the Drakaina microfauna offers not only environmental implications but also stratigraphical data about certain contexts. Since the study of Drakaina microfauna has not been completed, we hope that such information will be multiplied.


Bibliography

Αndrews, P. 1990. Owls, Caves and Fossils, Chicago.

Arnold, E. N., Burton, J. A. 1992. A field guide to the Reptiles of Britain and Europe, London.

Brothwell D., Jones, R. 1978. The relevance of small mammal studies to Archaeology, in Brothwell D. R., Thomas K.D., Clutton-Brock J. (eds.), Research problems in zooarchaeology, Insitute of Archaeology Occasional Publication 3, London, 47-57.

Mitchell-Jones, A. J. et.al. 1999. The Atlas of European Mammals, London.

Ondrias, J. 1966. The taxononmy and geographical distribution of the rodents of Greece, Saόgetierkundliche Mitteilungen 14, 1-136.

Stahl, P. W. 1996. The Recovery and Interpretation of Microvertebrate Bone Assemblages from Archaeological Contexts, Journal of Archaeological Method and Theory, Vol.3, No.1, 31-75.

Stratouli, G. 2007. Tracing the Ionian Neolithic: The contribution of recent excavations in Drakaina Cave, Poros, Kephalonia (in Greek with a summary in English), in G. Arvanitou-Metallinou dir., Prehistoric Corfu and its adjacent areas. Problems - Perspectives, Proceedings of the Meeting in Honour of Augustos Sordinas, Corfu 17 December 2004, Corfu, Hellenic Ministry of Culture, 105-126.

 

May 2009
Katerina Papayianni

 

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