SSS 2010-02-26（在线收听）

Bring home a bucket of fried chicken and you may find that people have strong feelings about which part of the bird is best. Well, scientists at Washington University in St. Louis say the answer is: the eyes. At least when you compare them to our own ocular implements. Because chickens can see more colors than we do, findings that appear in the journal Public Library of Science ONE.

The ability to see colors comes from specialized light-sensing cells found in the retina. These cells, called cones, come in different flavors, each of which can detect different wavelengths of light. Humans have three kinds of cones that allow us to see red, green and blue. But birds have an extra cone for seeing violet and ultraviolet light. What’s more, these chicken cones are distributed evenly throughout the retina, enhancing the birds’ ability to see colors all around their visual field.

Woodpeckers, sparrows and pigeons have a similar setup in the retina department, which presumably gives them an advantage when it comes to finding mates or spotting brightly colored berries. It may also explain why the chicken crossed the road. If you could see what he does, maybe you’d head over there, too.