Emily Chan
In contrast, the South African sites are a lot younger and are all associated with Homo sapiens. They are usually already exposed by the time they are discovered.
However, they are not as well-preserved as the East African ones because they are unprotected from the elements and the harsh dune sand. In addition, they are vulnerable to erosion, so researchers must work quickly to document them.
For the tracks on the Cape South Coast, researchers use a technique called optically stimulated luminescence to determine how old they are.
This dating method shows how long ago a sand grain was exposed to sunlight. The sediments at the Cape South Coast are rich in grains of quartz, which help make more precise age estimates.
The 153,000-year-old track was found in the Garden Route National Park, which is located west of the coastal town of Knysna.
Nahoon and Langebaan, the two previously dated South African sites, are about 124,000 years old and 117,000 years old.
The research team that conducted the work is based in the African Centre for Coastal Palaeoscience at Nelson Mandela University in South Africa. The team believes that more hominin tracks are out there, just waiting to be discovered.
They expect the list of sites to be much longer in a decade from now. They will be able to improve their understanding of ancient human ancestors in Africa.
