Why do tigers have stripes? The other big cats tend to have spots.

Linda Veron, Tarragona, Spain

A lady was wearing a black and white striped cardigan, and from close up I could see the separate stripes clearly, but when she walked away and got to about 20 metres distance from me the colours seemed to fuse together and go grey.

I'm assuming this is because the gaps between the stripes became too small for my eyes to define them.

So is this an unrecognised evolutionary advantage (being able to watch television the way we do doesn't count) or simply a fault with our eyes?

Many thanks,

Lana