So why is he so happy? What is it that makes him feel joy every second of his life? Scientists at the Cat Institute of Brains were equally curious about this constant contentedness that Happycat seems to always display. After analyzing and comparing Happycat's brain to a normal cat's brain, the reason was clear. Happycat has an astoundingly large happiness gland. So large that all of the other parts of his brain have to be tiny in order to fit in his head.