Monday, August 09, 2010

new hypothesis for human evolution and nature

Physorg | It's no secret to any dog-lover or cat-lover that humans have a special connection with animals. But in a new journal article and forthcoming book, paleoanthropologist Pat Shipman of Penn State University argues that this human-animal connection goes well beyond simple affection. Shipman proposes that the interdependency of ancestral humans with other animal species -- "the animal connection" -- played a crucial and beneficial role in human evolution over the last 2.6 million years.

"Establishing an intimate connection to other animals is unique and universal to our species," said Shipman, a professor of biological anthropology. Her paper describing the new hypothesis for human evolution based on the tendency to nurture members of other species will be published in the August 2010 issue of the journal Current Anthropology.

In addition to describing her theory in the scientific paper, Shipman has authored a book for the general public, now in press with W. W. Norton, titled The Animal Connection. "No other mammal routinely adopts other species in the wild -- no gazelles take in baby cheetahs, no mountain lions raise baby deer," Shipman said. "Every mouthful you feed to another species is one that your own children do not eat. On the face of it, caring for another species is maladaptive, so why do we humans do this?"

Shipman suggests that the animal connection was prompted by the invention of stone tools 2.6-million years ago. "Having sharp tools transformed wimpy human ancestors into effective predators who left many cut marks on the fossilized bones of their prey," Shipman said. Becoming a predator also put our ancestors into direct competition with other carnivores for carcasses and prey. As Shipman explains, the human ancestors who learned to observe and understand the behavior of potential prey obtained more meat. "Those who also focused on the behavior of potential competitors reaped a double evolutionary advantage for natural selection," she said.