Photo: Ardi's Secret: Did Early Humans Start Walking for Sex?



Editor's note: At the request of illustrator J.H. Matternes and Science/AAAS, we are removing the illustration of Ardipithecus ramidus that was once featured here. Illustrations of "Ardi" may be viewed in a scientific paper.

The skull of the world's oldest known skeleton of a human ancestor—4.4-million-year-old "Ardi," after her species Ardipithecus ramidus—is shown in a digital reconstruction.

According to at least one scientist, Ardi's apparent ability to walk on two legs may have been related to a revolutionary development in human evolution: monogamous sex.


Image courtesy Science/AAAS

NEWS FEEDS    After installing a news reader, click on this icon to download National Geographic News's XML/RSS feed. After installing a news reader, click on this icon to download National Geographic News's XML/RSS feed.

Get our news delivered directly to your desktop—free.
How to Use XML or RSS

ADVERTISEMENT

NATIONAL GEOGRAPHIC'S PHOTO OF THE DAY

50 Drives of a Lifetime

Listen to your favorite National Geographic news daily, anytime, anywhere from your mobile phone. No wires or syncing. Download Stitcher free today.