LONDON, May 26 (UPI) -- U.K. researchers say ultraviolet light that causes the temporary but painful condition of snow blindness in humans is life-saving for reindeer in the arctic.
The ability to see in the ultraviolet band of the light spectrum is part of a unique ability to adapt to the extreme arctic environment where reindeer live, researchers said.
"We discovered that reindeer can not only see ultraviolet light but they can also make sense of the image to find food and stay safe," Glen Jeffery of University College London said. "Humans and almost all other mammals could never do this as our lenses just don't let UV through into the eye."
Humans can see light with wavelengths down to 400nm, which corresponds to violet.
Researchers testing reindeer vision found they can handle wavelengths down to around 350-320nm, dubbed ultra-violet because it exceeds the extreme of the so-called visible spectrum of colors.
In arctic winter conditions, the ground is covered in snow and the sun is very low on the horizon, sometimes barely rising in the middle of the day, making it dark for most of the time.
Light is scattered in these conditions to the point where most light that reaches objects is blue or UV.
Arctic reindeer are able to let UV into their eyes and use the information effectively in their environment without suffering any of the affects that can damage human vision, the researchers said in their study sponsored by the U.K. Biotechnology and Biological Sciences Research Council.
