I see the deer in the garden more often now. A few days ago the group of deer paused so I could get a look at them and there was a large one which is probably the one I saw several days ago which was assumed to be a cougar. They can apparently see me inside at dawn even though I only have a lamp and the computer light.
In August 1992, a group of leading deer researchers and vision
scientists gathered at The University of Georgia (UGA) in Athens to
conduct this landmark study. The group of researchers included Drs. R.
Larry Marchinton and Karl V. Miller, and myself from UGA, Dr. Gerald H.
Jacobs and Jess Degan from the University of California, and Dr. Jay
Neitz from the Medical College of Wisconsin. This study was made
possible due to a highly sophisticated computer system developed by Dr.
Jacobs. This system is based on the principle that an electrical
response is produced when light enters the eye. The computer interprets
these responses and translates them into a “scientific best guess” of
what deer can actually see.
Findings of the Study
The results of our study confirmed that deer possess two (rather than
three as in humans) types of cones allowing limited color vision (Figure
1). The cone that deer lack is the “red” cone, or the one sensitive to
long wavelength colors such as red and orange. This suggests that
wearing bright colors while hunting does not affect hunting success.
This does not mean that these colors are invisible to deer, but rather
that they are perceived differently.
Deer are essentially red-green color blind like some humans. Their
color vision is limited to the short (blue) and middle (green)
wavelength colors. As a result, deer likely can distinguish blue from
red, but not green from red, or orange from red. Therefore, it appears
that hunters would be equally suited wearing green, red, or orange
clothing but perhaps slightly disadvantaged wearing blue.
The results regarding the UV capabilities of deer were equally
fascinating. Our results confirmed that deer lack a UV filter in their
eye and that their vision in the shorter wavelengths was much better
than ours. Deer also were found to have a relatively high sensitivity
(good vision) in the short wavelengths where UV brighteners and dyes are
While not entirely conclusive, this finding suggests that deer are
capable of seeing some UV light and that fabrics containing UV dyes and
brighteners may be more visible to deer than to humans.