There's a debate going on in the world of paleontology right now. Recently, researchers Jack Horner and John Scanella have suggested that one of two famous ceratopsians (or three-horned dinosaurs), Triceratops and Torosaurus, may not actually exist. Before I go any further with this, I'll explain a little bit more about these two dinosaurs.
Everyone knows what a Triceratops. Triceratops was one of the last dinosaurs ever to have walked the Earth, living sixty-five million years ago during the late Cretaceous period in what is now western North America. It was discovered in the year 1887 as a pair of horns. Paleontologist Othniel Charles Marsh at first thought they belonged to an extinct bison, but later realized he was wrong when a complete skull was found in 1888 and gave it the name Triceratops (Greek for Three-Horned Face). Ever since Triceratops has become a popular dinosaur among the people of the world, appearing in films and TV shows like Jurassic Park, The Land Before Time, and Dinosaur King. Triceratops probably lived in herds and lived its days eating, jousting with other members of the herd, and staying off the menu.
This next ceratopsian was known as Torosaurus. It's name, which means Perforated Lizard because of the holes in the frill (but some people think it means Bull Lizard), was given to it in the year 1891 by Othniel Charles Marsh (even though the original pair of skulls were found by John Bell Hatcher). Like Triceratops, Torosaurus also lived during the late Cretaceous period sixty-five million years ago in what is now western North America. The behavior was also most likely similar to Triceratops, roaming around in herds, flirting with and competing for girls, and doing its best to not end up as another dinosaur's dinner. The frill makes the head of Torosaurus about one-third the size of its body (a prehistoric big head). This was probably so it could easily attract females with bright colors (like most birds do today) and intimidate a predator by making it think that it was bigger than it really was.
The scientists Jack Horner and John Scanella have theorized that Triceratops and Torosarus were not two different dinosaurs, but one species. Their reason: The skulls of Triceratops get longer as they get older, and no juvenile Torosaurus has been found. Jack Horner in his studies found out that Triceratops skulls had two thin spots in the frill that correspond to the holes that are found on the skulls of Torosaurus (probably to help distribute the weight of the skull). After studying the skulls of twenty-nine Triceratops and nine Torosaurus, they concluded that Torosaurus was actually a fully mature Triceratops. Since the name first given to an animal is the one that prevails, it looks like that Torosaurus may vanish from the face of the Earth just like the dinosaurs vanished sixty-five million years ago.