“ Many different species of dinosaur live in forests. Triceratops, one of the biggest in North America. They can be 26 feet long. The huge frills on their heads can be used for protection when they fight. ”
Triceratops (Three-horned Face) is a genus of chasmosaurine ceratopsid dinosaur that lived in western North America 68 - 66 million years ago, during the Maastrichtian stage of the Late Cretaceous Period. It is one of the most common and most successful dinosaurs of its time and place, and as a result left several fossils, enough for it to become one of the most well-known dinosaurs to have ever walked the Earth. The animal depicted on Prehistoric Planet is likely the type species, Triceratops horridus, with its shorter nose horn and shallower snout.
A young adult Triceratops shows off his undamaged horns
“ This young male looks to be in prime condition, showing off his meter-long horns and his colorful head frill. His horns appear perfect, not yet damaged by battle. To a female, however, the absence of any wear and tear might suggest a potentially-critical weakness; a lack of experience. ”
Triceratops is one of the last ceratopsians, known to most as the horned and frilled dinosaurs, being the most recognizable member of its group. The iconic brow horns of Triceratops, each at least a meter (3 feet, 4 inches) long, along with their wide frills of solid bone (as opposed to the frills of other ceratopsids, which tend to have holes to lighten their weight) that could be as long as a third of the animal's whole length. One of the largest-known Triceratops skulls, nicknamed "Dragon King", is 2.75 meters (9 feet) long and 1.6 meters (5 feet, 3 inches) tall, though its skull is 1.4 meters (4 feet, 7 inches) wide, narrower than those of other large Triceratops fossils.[2][3] A second remarkable specimen, the subadult MOR 3027 (nicknamed "Yoshi's Trike" after its discoverer, Yoshi Katsura), has horns 1.15 meters (3 feet, 9 inches) long.[5] Accounting for keratin sheaths and the fact that "Yoshi's Trike" was not yet fully mature when it died (having only reached a length of 6 meters, or 20 feet),[9][10] fully-grown Triceratops possibly had horns that grew longer than 1.2 meters (4 feet). On Prehistoric Planet, "Yoshi's Trike" likely served as the basis of the 30 year-old, 10-tonne veteran male seen in the fourth segment of North America.
The same young adult Triceratops, with his left horn snapped off during a one-sided fight with an older, stronger male
Similar to their pachycephalosaur cousins,[11][12][13] ceratopsians like Triceratops have skulls that are composed of fibrolamellar bone which contains fibroblasts that rapidly deposit bone for the purposes of replacing or reshaping old and damaged bone tissue with new bone tissue, for the process of healing bone is important to animals that frequently use their heads for purposes that inevitably lead to wear and tear (though, as indicated by the damages that ceratopsian skulls bear, fibrolamellar bone would not be able to perfectly heal all the injuries that the animals sustain). However, as the animal's frill lengthened and expanded, it got thinner and more fenestrated (porous) to keep the head from becoming too heavy. As most of the frill is dense yet thin and porous, it would not have been well-suited to defending the animal,[8] though, because of its size, the frill would still be a convincingly intimidating display and shield to all but the most experienced hunters and rivals. On the other hand, due to the high amount of bone in the skulls of marginocephalians like ceratopsians and pachycephalosaurs, their heads are more durable than the rest of their skeletons, and are thus the most likely to be fossilized, as indicated by over 50 Triceratops skulls discovered in the Hell Creek Formation alone.[14]
Veteran Triceratops bellowing in victory, with a T. rex bite mark visible on the right side of his frill
One such example that showcases the resiliency of this animal is another possible inspiration for its portrayal in the series, a Triceratops horridus specimen known as "Big John", discovered by paleontologist Walter W. Stein in May 2014, and named after John R. (whose surname is withheld to protect his privacy), the owner of the ranch where the fossil was found in.[15] Known from more than 200 bones (making up 60% of the entire animal),[1] "Big John" is 5 - 10% larger than other known Triceratops specimens, and is hence set in the Guinness World Records as the largest Triceratops skeleton ever discovered.[6] It stood 3 meters (10 feet) tall, 8 meters (26 feet) long,[1] with a skull that is 75% complete, 2.62 meters (8 feet, 7 inches) long and 2 meters (6 feet, 7 inches) wide, with horns 1.1 meters (3 feet, 7 inches) long.[6][4] Flavio Bacchia, who supervised the specimen's assembly, determined that "Big John" was 60 years old when it died.[7] "Big John" has a partially-healed gaping hole on the right side of its frill, measuring 20 centimeters (8 inches) long and 5 centimeters (2 inches) wide, and it is believed that this was the result of a rival Triceratops attacking "Big John" from behind, further supporting the use of their horns in intraspecific combat. Based on how long modern reptiles heal similar traumatic injuries, as well as the size of the lesion and the extent to which it healed (with the margins of the wound being porous and disorganized, indicating new bone growth and remodeling), "Big John" likely died six months after being wounded, albeit due to causes unrelated to the injury.[16]
Jaws and Dentition[]
A Triceratops herd feeding on toxic plants
The front part of a Triceratops bill is toothless, while the rest of the mouth is packed with "dental batteries", tightly-packed teeth. Unlike hadrosaurids, which developed their dental batteries into grinding surfaces to grate plants into fine pieces, ceratopsians evolved their teeth to provide cutting surfaces for shearing through tough vegetation, with this difference in function indicating that they evolved their chewing capabilities independently.[17][TH 1] Ceratopsids are believed to have only fed on plants that were, at most, just one meter (3 feet) in height,[18] while gut microflora broke down plants in their stomach via fermentation.[19]
Veteran Triceratops bellows before starting a battle against a rival
On Prehistoric Planet, ceratopsians like Triceratops and Pachyrhinosaurus are depicted with cheeks, in sharp contrast with the other type of marginocephalians, pachycephalosaurs like Pachycephalosaurus and Prenocephale, which are depicted without cheeks. Using the works of Dr. Ali Nabavizadeh as justification, Dr. Darren Naish, lead consultant of Prehistoric Planet, brought up how pachycephalosaurs had simpler, more primitive teeth,[DN 1] and hence chewed food more like a lizard rather than doing so in the more complex manner in which ceratopsians and ornithopods chewed.[AN 1][DN 2] Regardless of how this debate eventually gets resolved, current understanding has it that dinosaur cheeks are not like those of mammals, since, contrary to popular belief, dinosaurs did not need cheeks to hold food,[AN 2] and one theory is that they may have had "cheeks" as a result of jaw muscles extending across the parts where true cheeks would be.[AN 1][TH 2]
Prehistoric Planet depicts Triceratops as mottled green with beige countershading. Also, based on evidence, the ceratopsians of the series are shown with large, polygonal scales and feature scales, along with a forelimb gait unlike that of large, quadrupedal mammals.[DN 3] The adults show individual variation in terms of head ornamentation, with females having yellow stripes running down their frills and thin horns that curve upwards and fork out, forming a wide, V-shaped gap between them, while males have blood-red frill stripes and thicker horns that tend to curve downwards then forwards, usually closer together, almost parallel to each other. The lengths of the horns also vary, likely due to age, some sport asymmetrical horn lengths or bear some battle damages, like horn tips chipped or even snapped off. The 30 year-old male from the fourth segment of North America even bears a large notch on the right edge of his frill, possibly a bite mark from a Tyrannosaurus. Juveniles, stated in the second segment of Forests to weigh a fiftieth of their parents, also have their appearance based on discovered differences between them and the adults, like shortened faces and horns turned upward in an almost-vertical orientation.[DN 4]
The skulls of two Triceratops, Quetzalcoatlus, Mosasaurus, and Barbaridactylus in the opening of the second season's episodes
The skull of a Triceratops, with the skulls of a Quetzalcoatlus, Mosasaurus, Barbaridactylus, and a smaller Triceratops skull in the background, appears in the opening of every episode of Prehistoric Planet's second season. Triceratops first appears in the second segment of Freshwater, where a T. rex feeds on a large Triceratops it took down just recently. Triceratops next appears in the second segment of Forests, which shows a small herd of them traveling to a cave in order to consume the mineral clay needed to neutralize the toxins of the plants they ate. The ceratopsians make a brief appearance in the fifth and final segment of Swamps, where several of them gather to feed on the lush vegetation, all the while keeping an eye out on two T. rexes in the area, looking for their next prey. The species makes one last appearance in the fourth segment of North America, where several of them gather in the forests near the Rocky Mountains for the mating season.
Triceratops is also the focus of an Uncovered segment, "Why Did Triceratops Have A Frill?", which discusses the purpose of their frills for display and defense. Additionally, Triceratops was featured in "Triceratops Forest", the second episode of Prehistoric Planet Immersive, where a herd of them gets involved in an intense standoff against dromaeosaurs.
The Lance Formation of Wyoming, USA, setting of the fourth segment of North America
“ Further north, the Rocky Mountains are still slowly rising. And as they do, they create higher, cooler landscapes where vast pine forests flourish. ”
Triceratops lived 68 - 66 million years ago in Laramidia, an island continent that would one day become western North America, which, by that time, was split in half by an inland sea. Given the formations it appeared in, Triceratops appears to prefer subtropical inland forests, swamps, and rivers (as seen in the Hell Creek Formation, which, though warmer than Montana and South Dakota today, was kept humid by sufficient levels of rainfall).
A cave of mineral clay that Triceratops herds frequently visit
“ At last, the herd reaches the place they need to visit. This is the antidote; a special clay. These are known as clay licks, and they're visited time and again. ”
It is justifiably plausible that, like some animals today, Triceratops may have engaged in geophagy (consumption of earth) to protect their stomachs from the toxins of the plants they ate. In the newly-forming Rocky Mountains, it is believed that there were limestone caves during the time of Triceratops, providing possible clay lick sites for the dinosaurs.[DN 5]
Paleofauna[]
A selection of non-avian dinosaurs that lived in the Hell Creek, Lance, and Scollard Formations (Triceratops horridus on the right side, in dark red)
“ Here, in spring, new plant growth creates new feeding grounds for the gathering herds. But where there are large numbers of plant-eaters, there are great hunters... ”
Triceratops coexisted with animals like Edmontosaurus, Ankylosaurus, and Pachycephalosaurus, as well as some dromaeosaurs like Acheroraptor and troodontids like Pectinodon. Given their large size, adult Triceratops would have only needed to be wary of one hunter, the apex predator of the regions it lived in, Tyrannosaurus rex. Triceratops also coexisted with Torosaurus, a similarly-sized ceratopsian with one of the largest heads of any land animal (with one specimen, "Adam", possessing a skull with a length of 3 meters or 10 feet),[20][21] made light by holes in the frill (as opposed to Triceratops, which has a shorter frill of solid bone). In the past, it was suggested that Torosaurus was a more mature form of Triceratops, though this theory is not that supported today, especially given the presence of very old Triceratops specimens like "Big John"[1][4][7][16] as well as apparently subadult Torosaurus specimens.[22][23][24] Another ceratopsian, the dog-sized Leptoceratops (around 2 meters, or 6 feet and 7 inches, in length), also lived in the Hell Creek, Lance, and Scollard Formations.
In a 2011 study that estimated the proportions of large-bodied dinosaurs in the Hell Creek Formation, it was revealed that Triceratops made up 40% of all dinosaurs found in the region, making it the most common dinosaur in Hell Creek, with T. rex (making up 24% of Hell Creek's dinosaur population) being the second most abundant, followed by Edmontosaurus, which made up 20% of Hell Creek's dinosaur population.[25] Of all the Triceratops skulls ever found, over 50 have been discovered in Hell Creek alone.[14]
As one of the last non-avian dinosaurs, Triceratops, along with most of the animals it coexisted with, would have bore witness to the Cretaceous-Paleogene Extinction Event 66.043 million years ago,[26] a catastrophe that ultimately wiped out three-quarters of all life on Earth, including all non-avian dinosaurs. However, as the species depicted on Prehistoric Planet appears to be the earlier T. horridus (given its shorter nose horn and shallower snout) rather than the later T. prorsus, which likely descended from it,[27][14] the ceratopsian seen on the show was no longer present by the time of the cataclysmic event.
Feeding Preferences and Adaptations[]
Triceratops scraping mineral clay off of a cave wall
“ A journey through an underground cave in North America turns perilous when a young Triceratops is separated from its mother. ”
― The official Apple TV+ episode synopsis for Forests
In terms of feeding, the type of plants Triceratops ate is still not entirely clear, with suggestions ranging from palms and cycads to ferns. It is presumed that, with its deep, narrow beak, Triceratops plucked low vegetation (though the animal could potentially ram and knock down taller plants and trees), and sheared through these large volumes of fibrous plants with its dental batteries. Prehistoric Planet depicts Triceratops as practicing what some elephants do today, heading for caves to ingest minerals.[28][29] Animals engage in geophagy (the consumption of soil) either to counteract and neutralize the toxins of the plants they ate, or to supplement their diet with extra nutrients (animals that tend to do this usually live in areas or conditions where nutrition is poor and essential minerals are hard to come by). Prehistoric Planet went with the former reason, though the latter is still considered a possibility.[DN 5]
Social and Mating Behavior[]
Triceratops herds only consist of around less than a dozen members
“ The mating season has arrived for one of North America's most heavily-armed dinosaurs. Triceratops. Every year, large numbers of these giants gather in clearings. The females have come to choose a mate. Six-tonne males fight and display their strength. ”
In terms of social behavior, unlike most ceratopsids (mostly centrosaurines, which have been found in mass bone beds), Triceratops does not appear to travel in large herds numbering in the dozens. Remains of several Triceratops indicate that they traveled in small groups of 5 - 10 individuals, which can be observed in second segment of Forests and the fifth segment of Swamps.[30] This is supported by the discovery made by a team from Naturalis Biodiversity Center in the Netherlands that was involved in a fossil-digging project in Wyoming that lasted for eleven years, from 2013 to 2024. The excavation revealed five young Triceratops that were likely buried in a swamp 67 million years ago.[31] It is unknown whether this was a proper group or a "bachelor herd", a temporary herd which consists of subadults that were forced out of their parent herd, looking for females to form a herd of their own (at which point they separate from the bachelor herd).[32] The only time more appear to come together is during the mating season, as seen in the fourth segment of North America, where large numbers of them gather in clearings, with the females looking for suitable partners, and males fight and show off their strength to cement their mating priorities.
Agonistic Behavior[]
A T. rex eating a Triceratops starting from the neck
“ T. rex are built for hunting large herbivores, and many of those have evolved heavy defensive weapons. ”
In terms of fending off threats, the large horns, frill, and overall size and mass of Triceratops are enough to serve as a warning of the brute force that the ceratopsian is capable of bringing forth, making it one of the most dangerous animals in western North America by the end of the Cretaceous Period. Even so, this is not a guarantee of their safety, as seen in the second segment of Freshwater, where one was just recently slain by an old male Tyrannosaurus, which, as indicated by his many scars and wounds (including the new ones the Triceratops inflicted on his right leg in the struggle), has gone through decades of fighting and bringing down large, dangerous prey, and still lived to fight another day. This segment depicts the old T. rex feeding on the Triceratops starting from the neck. As a study in 2012 suggests, T. rex likely focused on the nutrient-rich neck muscles behind the frill of a Triceratops (which, in life, were necessary to help the ceratopsian support the great weight of its head).[33] Conversely, the 30 year-old veteran male Triceratops in the fourth segment of North America appears to have what is likely a T. rex bite mark on the right edge of his frill, an indication that, much like the old T. rex from the second segment of Freshwater, he, too, has fought and possibly even brought down dangerous predators, his continued survival serving as proof of his experience and dominance in life.
A 30 year-old male (left) overpowering a younger rival in a pushing match
“ A 30 year-old male, weighing more than 10 tonnes. If there's one thing that he has in spades, it's decades of wear and tear. He may be old, but he's still strong enough to challenge a young rival, however fit. The stakes are high, and neither is willing to back down. ”
Triceratops could also clearly use their horns for fighting others of their own kind. To settle disputes, the males would lock horns, using their weight and experience to overpower the enemy and emerge victorious. This can result in all sorts of injuries, from snapped horns to even punctured frills, as was the case for the "Big John" specimen. Even so, as tough animals, Triceratops are expected to heal and recover from such injuries, as "Big John", believed to be 60 years old at the time of its death, apparently did not die as a result of its large traumatic lesion.[16] The fibrolamellar bone that makes up their skulls contains fibroblasts that rapidly deposit bone to quickly repair damages that they sustain, but as their numerous preserved injuries show, the healing process would not completely remove all the violent traces of their agonistic behavior,[8] and this is not necessarily a negative aspect, as scars provide solid evidence of an individual's experience as a strong fighter and survivor, making them more intimidating to enemies (predators and rivals of the same species alike) and more attractive to members of the opposite sex.
Gallery[]
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↑Reid REH (1997) Histology of bones and teeth. In: Currie, PJ and Padian, K, editors. Encyclopedia of Dinosaurs. Academic Press, San Diego, CA. 329–339.
