Bearing a large bony frill, three horns on the skull, and a large, four-legged body, exhibiting convergent evolution with bovines and rhinoceroses, Triceratops is one of the most recognizable of all dinosaurs and the best-known ceratopsian.
It was also one of the largest, up to 8–9 metres (26–30 ft) long and 5–9 metric tons (5.5–9.9 short tons) in body mass. It shared the landscape with and was most likely preyed upon by Tyrannosaurus, though it is less certain that two adults would battle in the fanciful manner often depicted in museum displays and popular media.
The functions of the frills and three distinctive facial horns on its head have inspired countless debates. Traditionally, these have been viewed as defensive weapons against predators. More recent interpretations find it probable that these features were primarily used in species identification, courtship, and dominance display, much like the antlers and horns of modern ungulates.
What strikes me most about this picture is the weight. The triceratops femur is not much longer, but it's like twice as thick. The weight it must have bore is simply incredible when you think of alligators as our largest reptiles alive now.
Dinosaurs were beyond massive. The vegetation required to feed these giant herbivores must have been astounding.