OTTAWA SUN (Ontario) 21 July 06 Snake Fears Honed Human Vision, Docs Report
Washington (Reuters): Snakes may make people jump for a good reason -- human close-up vision may have evolved to spot the reptiles, researchers reported yesterday.
Humans, monkeys and other primates have good colour vision, large brains, and use their vision to guide reaching and grasping.
But while some scientists believe these characteristics evolved together as early primates used their hands and eyes to pick fruit and other foods, Lynne Isbell, a professor of anthropology at the University of California Davis, believes they may have evolved to help primates evade snakes.
"A snake is the only predator you really need to see close up. If it's a long way away it's not dangerous," said Isbell, who has published her theory in the Journal of Human Evolution.
Mammals evolved about 100 million years ago and fossils of snakes with mouths big enough to eat those mammals appear at about the same time, she pointed out.