Triceratops, https://en.wikipedia.org/wiki/Triceratops
 Castro, Joseph, Triceratops: Facts About the Three-Horned Dinosaur, http://www.livescience.com/24011-triceratops-facts.html
Triceratops is an extinct quadrupedal dinosaur with three horns and a large bony frill on the back of its head that lived in what is now western North America. The horn over their nostrils was small and those over their eyes may have grown to over three feet long as they mature. Their heads were among the largest of all land animals being about one third of the length of their bodies. They had relatively short tails as compared to other dinosaurs. By adulthood, Triceratops is estimated to have grown to 30 feet long and 10 feet high. Their limbs were stout with the hind limbs larger.
There is little question that they were herbivores with beaks to snip off vegetation and groups of teeth behind to grind up their food. Each side of their jaw had 36 to 40 tooth columns with 3 to 5 stacked teeth per column and teeth were continually being replaced. 
It is uncertain but likely that Tyrannosaurus Rex was a predator of Triceratops based on some indications of teeth marks on its fossils. Triceratops may have been able to ward off attacks by inflicting severe or fatal damage to the predator with its large horns.
Triceratops fossils have been found in the USA (Montana, South Dakota, North Dakota, Colorado, and Wyoming) and Canada (Saskatchewan and Alberta).  No whole Triceratops skeletons have been found. Their skull fossils, both complete and partial, are fairly common while fossils of other parts of their skeleton are much less common. As no fossilized Triceratops eggs have been found, their mode of birth is uncertain. In the past, a number of fossils have been found that were thought to be species similar to Triceratops but may in fact be just different changes in Triceratops as it aged and/or differences between male and female skeletons.