The top of Pachycephalosaurus' head was covered in a large, thick dome that could grow up to 10 inches thick. It was likely covered in a keratin sheath, the same material as human nails. This "head dome" gave Pachycephalosaurus its name, which translates to "thick-headed lizard." Most scientists believe they used this dome to head-butt rivals. Some scientists argue that the bone is too spongy to absorb a direct hit from another Pachycephalosaurus and that it may have been used for ramming into the side of other dinosaurs, rather than head-to-head combat.
Around the base of the head dome and on top of the dinosaur's snout were a series of smaller spikes. While the exact purpose of the spikes is unknown, scientists theorize they were used for identify one another or to mark sexual maturity.
Pachycephalosaurus used its long, muscular back legs for walking and running from predators. A recent study suggests they may have even used their legs to kick predators!
Pachycephalosaurus at the Akron Zoo
Pachycephalosaurus is located near the bald eagle habitat.