When we think about animal camouflage, it's about the animal's appearance looking like its background so that it blends in. But there's a lot more to it than that. Camouflage effects, or nature's illusions, work as a combination of the way an animal looks and the way it is perceived by whatever it's hiding from. We might see a tiger and say, how is that camouflage? But if the cat's prey doesn't perceive colors the way we do, well, that just means we aren't a tiger's natural prey.
The science of perception is uncovering many different methods we use to sort and interpret the signals coming into our eyes and brain by studying the ways we can be fooled by those signals. Perception is an amazingly complex process that we use surprisingly well without understanding it. Animals think about it even less, but use it to survive. That's the way of natural selection- whatever works, in both perception and appearance, will become more common for those creatures who survive long enough to pass on their genes. It's only humans who survived and thrived long enough to study the details. This video is eleven minutes long; the rest is promotional. -via Laughing Squid