Period: Late Cretaceous
Order, Suborder, Family: Ornithischia, Marginocephalia, Homalocephalidae
Location: Asia (Mongolia)
Length: 10 feet (3 meters)
As its name ("even head") suggests, Homalocephale had a flat head unlike most pachycephalosaurs. It is known from limited but very good material. The single skull of Homalocephale is missing the front of the snout but is otherwise complete. This skull proves that the animal was a flat, thick-headed reptile. The back of the skull was high and hung slightly over the neck. The sides of the skull were slightly thickened and expanded. The top of the skull, as well as the cheek region and back of the skull, had spikes, bumps, and ridges of bone. The large eye sockets probably mean that Homalocephale, like many other pachycephalosaurs, had good vision.
There is other information scientists can find from its skull. There was a large area for the olfactory nerve (the nerve used for smelling). The size of this area suggests that Homalocephale had a good sense of smell. This is useful for any animal in the wild; it could have smelled a nearby predator and escaped before the predator saw it.
The teeth of Homalocephale show wear; it did a lot of chewing. It probably was a browsing dinosaur, feeding mostly on leaves and probably not eating many fruits.
Perhaps the most important information comes from the skeleton of Homalocephale. Stegoceras and Homalocephale are the only pachycephalosaurs known from both skulls and skeletons. From the skeleton of Homalocephale, we know that the thorax, abdomen, and pelvic area were extremely broad, perhaps for a large gut that was needed to digest a diet of plants.
The anatomy of Homalocephale provides information about the behavior of this animal. The flat head and rear shelf of the back of the skull may have been for display. They also may have been for head-butting, where males had contests of strength to win females or territory. The spine would have been held horizontally; this would be expected if an animal used its head to butt. Modern big horn sheep use the same behavior when they protect their harem and defend their territory against competitors.
Other flat-headed pachycephalosaurs related to Homalocephale included Wannanosaurus from the China and Goyocephale from Mongolia.