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Dinosaur species


The head of PachycephalosaurusThe head of Pachycephalosaurus Pachycephalosaurus lived in North America during the Late Cretaceous. Its most distinguishing feature was its smooth, high-domed head made of thick bone with bony knobs around the rear edge. Short, bony spikes jutted out from its snout and there were ridges over its eyes. It had tiny serrated teeth. Pachycephalosaurus had a short, thick neck, and a heavy, rigid tail. It ran on its hindlegs, holding its back and tail straight and horizontal as it did so. Its arms were short, with small claws.


Two males engage in a butting contest.Two males engage in a butting contest.Pachycephalosaurus with a head woundPachycephalosaurus with a head woundThe name Pachycephalosaurus means “thick-headed lizard”, after its thick-boned, domed skull. The skull bone became thicker as the dinosaur got older. The skulls of Pachycephalosaurus and its relatives may have been used for butting contests between rival males during the breeding season, just as rams and billy goats do today. This probably accounts for the serious injuries seen on the skulls of many Pachycephalosaurus.


Only skulls of Pachycephalo-saurus have ever been found. Palaeontologists have guessed its body proportions by studying the more complete remains of its relative, Stegoceras.

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