"Triceratops possessed a gigantic skull, and some individuals had skulls nearly 3 metres (about 10 feet) long, which would place them among the largest of all terrestrial animals. In addition to its three conspicuous horns, which were placed above each eye and on the snout, it possessed numerous small spikes (epoccipitals) that bordered the margin of the expanded frill of bone at the back of the skull. There were as many as 19-26 epoccipitals on the frill. Triceratops also possessed smaller hornlike projections on the jugal bones (cheekbones). The upper and lower jaws were lined with stacked columns of teeth, which appear to have been specialized for shearing. The front of the mouth formed a beak, which may have been used to crop vegetation. In addition, most of the skull was covered by indentations made by blood vessels; similar indentations are found under the keratinous beaks of living birds. This suggests that the dinosaur's entire head, aside from the cheeks and the area around the nostrils, was covered in keratin while it was alive. In many living birds, keratin is very colourful, a fact that suggests that the skulls of Triceratops may have been very colourful as well.
Triceratops is often portrayed as using its large horns to defend itself from contemporary carnivorous dinosaurs, such as Tyrannosaurus rex. The discovery of apparent pathologies (the results of disease or injury) in consistent locations of the frills supports the possibility that Triceratops may have engaged in intraspecific combat, as is seen in some extant horned animals. Another possibility is that the horns functioned primarily as display structures, perhaps for signaling relative maturity to other members of the group. This suggestion is supported by the fact that the horns and frill of Triceratops changed shape dramatically throughout its development, allowing juveniles to be differentiated from more mature animals.
The majority of Triceratops specimens are known from skulls or partial skulls, and bones from the rest of the body are less commonly recovered. From fossil remains of other parts of the body, paleontologists have been able to determine that the hind limbs of Triceratops were larger than the forelimbs, but both sets were very stout. Whether the forelimbs were held fully erect, as in the modern rhinoceros, is debated, though there is some evidence to suggest that they were held in a semisprawling position (an intermediate stance between the erect position of a rhinoceros and the fully sprawling limbs of most lizards). The dinosaur's short toes probably terminated in small hooves. The tail, as in many other large horned dinosaurs, appears to have been fairly short"(Scannella "Triceratops").
"In a 2010 study in the Journal of Vertebrate Paleontology, Scannella and his colleague John ("Jack") Horner argued that Torosaurus, which is mainly distinguished from Triceratops by having an expanded frill with large holes, was actually Triceratops in old age. "We found evidence that the frill on the back of the skull [of Triceratops] expands relatively late during growth," Scannella said, adding that the microscructure of Torosaurus bones suggests they are older than even the largest Triceratops specimens. 'This suggested that Torosaurus, rather than being a distinct genus, was actually a fully grown Triceratops.'"(Castro 2016)
"In a 2010 study in the Journal of Vertebrate Paleontology, Scannella and his colleague John ("Jack") Horner argued that Torosaurus, which is mainly distinguished from Triceratops by having an expanded frill with large holes, was actually Triceratops in old age. "We found evidence that the frill on the back of the skull [of Triceratops] expands relatively late during growth," Scannella said, adding that the microscructure of Torosaurus bones suggests they are older than even the largest Triceratops specimens. 'This suggested that Torosaurus, rather than being a distinct genus, was actually a fully grown Triceratops.'"(Castro 2016)