Jamal states that, even though Macs do not have print screen buttons like Windows or Linux PCs, you can still print screen on them. The insight is not commonly held among the population since most people can not see the print screen button.
Jamal, in his blog post found at http://printscreenmac.org/
Jamal also talks about two secret ways of capturing a screen. You can do that by using a program like GIMP or you can do it by using the print button.
"There are other ways to capture the screen. There are special programs you can obtain that will take a screenshot for you with a click of a button. Shutter is a good one, in fact, it is my favorite on Ubuntu Linux and Mac. For Windows, I usually stick to the print screen button as it does the job." he said.