14 DAY TRIAL // According to current knowledge, our ancestors first appeared in eastern Africa, where the oldest, human-like fossils were found. They are believed to have then left the continent in successive migrations, eventually spreading across the planet and beginning their domination of the world. However, historians and paleontologists have wondered for a long time how they got past the Sahara desert, one of the most ruthless places on the surface of the planet, NewScientist reports.
Now, a new set of studies points at the fact that it may have been spells of humidity that allowed Stone Age humans to leave the Cradle of Life. The conclusion is based on newly discovered knowledge that water-dependent trees and shrubs grew in the desert between 120,000 and 45,000 years ago. They could have not survived in a climate such as the present one, so they must have been receiving rain constantly. With the aid of rain, our ancestors might have easily undertaken the long roads that lay ahead.
The new investigation was conducted by a team of scientists from the Royal Netherlands Institute for Sea Research, led by expert Isla Castaneda. The investigators did not look for plant remains under the sand, but rather at sand deposits on the bottom of the Atlantic Ocean, off the coast of western Africa. They were looking especially for land-plant hydrocarbons in the deposits. When these concentrations were identified, the team analyzed the ratio of hydrocarbons to carbon isotopes, a study that allowed for them to draw a conclusion as to what type of plants lived in the Sahara up to 192,000 years ago.
The science team essentially identified two periods during which Sahara might have been subjected to wet spells. One of these periods took place between 120,000 and 110,000 ago, while the second one was in effect between 50,000 and 45,000 years ago. Outside of Africa, the oldest known human fossil at this point in time is one discovered in Israel, estimated to have lived some 93,000 years ago. This would be in tune with the parameters of the new model, the team says. The second migration that took place was the one that finally allowed Homo sapiens to move out of Africa and into Europe.