I'm not sure why I find nature's blues so appealing. I suspect it is because blue creatures are clearly there to stand out - it is unlikely to be camouflage - and therefore usually also somewhat flamboyant. This is combined with the fact that my mild red-green colour deficiency reduces the equivalent wow-factor of reds. Anyway, whatever the reason, here are a couple of great blue animals. The first is Homarus americanus, the American lobster, which is featuring in an undergrad practical I am running next week - or, at least, some DNA sequences are. (Picture from World Register of Marine Species.)
The second is even more spectacular: a close-up of a blue damselfly, which is part of a set of amazing photos in an item at The Telegraph website, Bug-eyed: macro photographs of insects by Ireneusz Irass Waledzik. Isn't it adorable‽ It's well worth checking out the complete set.