Cape Zone Was a Savanna During the Lifetime of the Early Humans

Analysis of fossil teeth helped scientists watching the climate and landscape shift in prehistoric South Africa.

South Africa is a landmark in human evolution, as here were discovered fossils of Paranthropus and also, one of the oldest remains of Homo sapiens.

Human evolution is supposed to have taken place in a grassy savanna.

But nowadays, the region comprises a unique biome, the fynbos, a type of Mediterranean shrubland (similar with matorral, maquis, or chaparral from other zones with Mediterranean climate), which presents the world's greatest plant diversity: over 8700 species (around 5000 endemic).

The team studied the teeth of bovids (that means antelopes and related species: cattle, sheep, goats) found in the fossil site at Langebaanweg (on the coast of South Africa ).

"We don't know much about how the fynbos began and whether it relates to human evolution," said Peter Ungar, professor of anthropology in the J. William Fulbright College of Arts and Sciences, University of Arkansas.

Savanna's expansion over forested landscape about 5 million years ago in eastern and perhaps southern Africa is seen as the main factor in triggering the evolution from ape to man.

Thus, scientists wanted to see if and when savanna landscape occurred in South Africa.

In order to understand the plant cover of those times, the team watched on the dental microscopic wear of the herbivorous which lived 5 million years ago in Western Cape Zone.

"We figured that if we could look at the microwear on (fossil) bovids, we could determine what the animals were eating," Ungar said, thus getting important clues of the prehistoric landscape.

The scientists used modified fractal analysis software and a state-of-the-art laser scanning microscope. The pits and grooves in bovid's teeth indicate what they ate.

A pit-laden texture indicates browsers (antelopes that consume softer plant items: bush leaves, offshoots, buds, fruits) like duikers or kudu (photo above), associated with scrub land or forested areas, while scratched texture of the grazers (grass eaters) like gemsbok (photo bellow) or wildebeest points to open landscapes.

The results revealed a shift in the markings on the teeth from browsing to grazing, which means that forests and scrub land gave way to savanna like environment.

"This is the first time that microwear texture data have suggested a dietary shift within a group of animals before," Ungar said.