Early Humans Climbed Down from Trees Gradually

The last common ancestor of humans and chimpanzees may have had shoulders that were similar to those of modern African apes, researchers say. The finding supports the notion that the human lineage shifted to a life away from trees gradually. Knowing the characteristics of the last common ancestor of humans and chimps would shed light on how the anatomy and behavior of both lineages evolved over time, "but fossils from that time are rare," said lead author of the new study Nathan Young, an evolut