People, of course, can't normally see UV light because our eye's lenses filter out UV rays and prevent them from reaching the retina. I've heard the claim about deer seeing UV light before—always from someone with a product to sell—so I've always taken it with a dose of skepticism. However, some recent scientific research suggests it's true.
The whitetail deer is certainly the most studied wild animal in North America, and the first studies I saw suggesting they can see into the UV spectrum were done solely by determining that UV light passed through their eye's lenses and reached the retina. This implied deer were actually utilizing that portion of the spectrum.
The fact UV light reaches the retina suggests it's being used, but doesn't really prove it. However, a behavioral study on whitetail deer done at the University of Georgia last year made that link. It determined deer do utilize this light to see, and could be trained to feed a certain way by using light invisible to humans. The researcher's findings indicate it can be useful for hunters to evaluate their clothing and other gear to ensure it doesn't reflect UV light.
I found the deer study fascinating, but since I'm primarily a varmint and predator hunter, I couldn't help but wonder if the same was true for the game I hunt. For that reason, a recently published study (Royal Society Publishing) out of the UK caught my attention. It examined 38 species of mammals and found many of them appear to use UV light extensively. The single canine they tested, a Labrador retriever, ranked fourth highest on the list in its ability to land UV light onto the retina. A cat ranked No. 6. This suggests wolves, fox, coyotes and bobcats can see UV light extremely well, and I should avoid using any equipment that glows under a UV light.
With all of this info fresh in my mind, I tested my hunting gear with the Streamlight Night Com UV flashlight I use in forensic work. Holy cow—some of it glows like a neon bulb! Other gear, which is the same basic color, is largely invisible.
The photo above shows the difference between two white camo jackets when illuminated with UV light. Can coyotes see the difference? I don't know, but I'm starting to think they can. The only thing I'm sure of now is I'm going to research this a little further. And I might be buying products like the one shown below.
P.S. Did you know North American Hunter has an online store?