The linked website has an interesting post about the origins of the Linux Tux mascot and why it was chosen over the other proposed symbols to represent the freedom and superiority of the Linux kernel over other operating systems. Turns out that it was Linus Torvalds that chose this animal as he is quite fond of Penguins and this was a natural decision on his part. And the Tux penguin is very cute and fat, an adorable mascot for a free and open kernel and associated open source software that builds a superior and secure operating system.
http://www.linuxscrew.com/2007/11/14/why-penguin-is-linux-logo/.