Why bother running on hind legs when the four you've been given work perfectly well? This is the question that puzzles Christofer Clemente. For birds and primates, there's a perfectly good answer: ...

Why Do Frilled-Neck Lizards Frill? Frilled-neck lizards frill their necks for a few different reasons, primarily for defense and communication. Frilled lizards use their frills to communicate with ...