[Megan]

Seeing the Serpent
July 19, 2006

The ability to spot venomous snakes may have played a major role in the evolution of monkeys, apes and humans, according to a new hypothesis by Lynne Isbell, professor of anthropology at UC Davis. The work is published in the July issue of the Journal of Human Evolution.

Primates have good vision, enlarged brains, and grasping hands and feet, and use their vision to guide reaching and grasping. Scientists have thought that these 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.

Isbell suggests instead that 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. If it's a long way away it's not dangerous," Isbell said.

Neurological studies by others show that the structure of the brain's visual system does not actually fit with the idea that vision evolved along with reaching and grasping, Isbell said.

But the visual system does seem to be well connected to the "fear module," brain structures involved in vigilance, fear and learning.

UC Davis News & Information :: Seeing the Serpent

Does anyone else think big cats, and wild animals in general, are a driver of evolutionary development in humans?