The story of Sophia Pedro, who gave birth while trapped in treetops during a flood in Mozambique in 2000, attracted the attention of the world's media after the mother and newborn were rescued by helicopter.

It also drew the interest of two anthropologists who have been collaborating on researching the evolution of the pelvis and childbirth from the times of the australopithecines, early ancestors of humans, who lived 4 million years ago.

Karen Rosenberg, chairperson of UD's Department of Anthropology, and Wenda Trevathan of New Mexico State University, who also is a midwife, recently published "The Evolution of Human Birth" in Scientific American. Their article begins with Pedro's story, pointing out that her delivery is far from the norm for humans, although many other primates do give birth alone in treetops.

"Human beings are the only primate species that regularly seeks assistance during labor and delivery," the article notes, explaining that humans have big heads because of their large brains, but the birth canal through which the baby must pass is limited by the constraints of humans' upright stance.

Rosenberg and Trevathan are collaborating on a book looking at childbirth from both a cross-cultural and an evolutionary viewpoint.