Dinosaurs by their nature seem bizarre, larger than life -- mysterious. And the history of dinos is constantly rewritten. Here we present to you 10 dinos that are furrier, freakier and more colorful than we previously thought possible.
Head-butting pachycephalosaurs, with noggins shaped like built-in football helmets, have long puzzled paleontologists.
"The head-slapping behavior of crocodiles and the face-pecking observed in a variety of birds suggest that 'using your head' is not unique to pachycephalosaurs," says Joseph Peterson, a geology professor at the University of Wisconsin. "Domes likely evolved in response to such behavior."