They waddled into stardom in National Geographic's <i>March of the Penguins</i> film. These guys are now nature's ROCK STARS! If you're age 5, you're probably as tall as an Emperor. But why do they throw up so much? March this way, and find out all!<br><br>National Geographic supports K-12 educators with ELA Common Core Resources.<br>Visit www.natgeoed.org/commoncore for more information.