Dinosaurs as a class must have owned large quantities of energy to pour into the rigors of courtship and mating, because head-butting evolved several times in different families. (realistic dinosaur)Tyrannosaurus rex’s massively thick skull edges, covered with horn, represent the acme of the evolutionary trend toward head-ramming among carnivores. Pachycephalosaurs, thick-headed dinosaurs described in a previous chapter, evolved huge, bowling ball shaped skulls very much like the ones carried by the dome-headed protomammals of the Late Permian. Some Polish scientists have suggested that head-ramming was too powerful to be used against sexual rivals and that the head-down charge at full tilt must have been employed against predators. However, the domes both on dome-headed protomammals and on dome-headed dinosaurs really resembled bony boxing gloves built atop the skull. (animatronic dinosaur)The boxing glove, even one of bone, delivers a blunt, stunning blow. If evolution had really been working to produce a deadly antipredator weapon, a spearlike point on the head would have been much more effective than a blunt dome. It seems far more feasible therefore to envisage the domes as ideal weapons for sexual contests without incurring the danger of esca-lating the match to the point where even the winner goes away mortally wounded. A mortally wounded winner doesn’t win in the game of evolution because dead heroes can’t mate.
Quite the reverse, however, must hold true for the headgear of Triceratops and the other long-horned dinosaurs. Recently, a pair of American paleontologists, apparently caught up in the rush to reinterpret dinosaur features as organs for sexual display, suggested the horns and frill on Triceratops were not for defending against Tyrannosaurus but for display to other Triceratops. (dinosaur costume)But the head ornaments of Triceratops were simply much too deadly to serve a sexual purpose. Those long, sharply pointed horns were for killing. The wide frill, sometimes edged with horn-covered spikes, served for protection against dangerous bites. The little horned dinosaurs, Protoceratops and its relatives, probably had started out designed for nonlethal jousting.(animatronic dinosaur factory) Their snouts were strong, but only the slight suggestion of a blunt horn grew above their nostrils. Large suites of Protoceratops skeletons from the red Mongolian sand dunes indicate that males had larger heads and stronger nose horns than females. So springtime probably did bring thoughts of sex and snout-butting into the minds of the little horned dinosaurs. But that could no longer have been true of their larger, far more lethally endowed descendants.