Why did some ceratopsians have head frills?
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The ceratopsian frills may have been the animal’s armor to protect itself from predators such as the Tyrannosaurs rex, which lived at the same time and locale as the Triceratops. There are other ceratopsians that had smaller frills or frills with large openings, which would have been less efficient for defense. Thus, some scientists suggest the frills may have been used as heat radiators, signaling devices, or for attracting mates. In fact, recent studies of the inside of the bony frill indicate that certain parts held different temperatures, thus supporting the idea that it served as a heat radiator.