Creation of an island: The extinction of animals on Zanzibar

Date: February 23, 2016

Source: University of York

Researchers at the University of York have been part of the first comprehensive study of how Zanzibar was formed, charting the extinction of various animals from the island.

In a collaborative project between environmental scientists and archaeologists, a team charted the history of sea level change by examining mangrove sediments, and conducting analysis on animal remains found in Kuumbi Cave -- an important archaeological site.

Focusing on evidence from three distinct time periods -- the end of the last Ice Age, the stage when Zanzibar became an island 11,000 years ago, and the time of being an island -- researchers found that numerous large mammals had disappeared by the latter stage.

Analysing over 6000 bone specimens, it was found that large fauna such as zebra, buffalo, waterbuck and gazelle were present in the time of island formation. However, after sea levels had risen and the island had been inhabited by coastal cultures, they disappeared. Other small fauna, such as porcupines and hares, were also no longer present.

Insights into sea level changes, combined with archaeological data on the history of the island's fauna through excavation, has never been done before in charting Zanzibar's history. This unique interdisciplinary approach provides a new, accurate account of the island's prehistory and defaunation.

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