Q. Do squirrels see the colorful fall display of red, yellow and brown leaves?

A. Squirrels do have color vision, but they cannot see the difference between the green leaves of summer and the red leaves of fall, researchers say.

A 1987 study of the tree squirrel, published in The Journal of Comparative Physiology A, analyzed their color vision using behavioral tests and examining the kinds of color-sensing nerve cells in their retinas.

The researchers concluded that the familiar gray tree squirrels, Sciurus carolinensis, have dichromatic color vision. This means that squirrels can distinguish red and green from other colors but cannot tell red and green from each other. This kind of color vision closely resembles red-green color blindness in humans.

The behavioral tests used lighted panels of different colors. The squirrels learned that when they touched the panel displaying a target color, a food pellet was released.