One of the dangers in biology is to look at some characteristic and assume what forces led to its evolution without ever actually testing that assumption.
Take the chameleon. It's pretty obvious that nifty color changing ability helps camouflage them allowing them to be both protected from predators and to catch more prey. Right? Well, no according to research published this week. Evidence suggests that the color change is for communication not camouflage.
'No one has ever shown that the chameleon's special ability provides camouflage, says Hanlon, who reviewed 100 years of scientific literature on the subject.'