I started wearing sunglasses while deer hunting a few years and one thing I noticed was the effect it had on animals.... squirrels anyway. The annoying red pine squirrels seem to be less bothered by me being there. Normally they alarm and chitter their warning like mad, but with the wrap around sunglasses on I've had them come right up to me seemingly without them knowing I was there. I guess without the eyes showing, they just think I'm a tree stump or whatnot.
And of course they are great in the snow and with early morning glare.
