DAVIS, Calif., July 20 (UPI) -- A U.S. anthropologist says the ability to spot venomous snakes may have played a major role in the evolution of monkeys, apes and humans.
University of California-Davis Professor of anthropology Lynne Isbell notes primates have good vision, enlarged brains and grasping hands and feet -- and use their vision to guide reaching and grasping.
Scientists have thought such characteristics evolved together as early primates used their hands and eyes to grab insects and other small prey, or to handle and examine fruit and other foods.
But Isbell hypothesizes primates developed good close-up eyesight to avoid a dangerous predator -- the snake.
"A snake is the only predator you really need to see close up," she said. "If it's a long way away it's not dangerous."
She also notes neurological studies have shown the structure of the brain's visual system doesn't actually fit with the idea that vision evolved along with reaching and grasping. But, Isbell said, the visual system does seem to be well connected to the "fear module," brain structures involved in vigilance, fear and learning.
The study is published in the Journal of Human Evolution.
