Ceratosaurus nasicornis (S/F)

Ceratosaurus, meaning “horned reptile” for the distinctive horn on its snout, is a species of small to medium-sized ceratosaurid theropod. It lived during the late Jurassic period from about 153 to 148 million years ago; the type species, C. nasicornis, is known only from North America, but fragmentary remains of other possible species have been found in Europe. Both parts of its binomial name refer to its horn; Ceratosaurus, of course, means “horned reptile,” while nasicornis means “nose horn.”

Ceratosaurus belongs to the infraorder Ceratosauria and to the family Ceratosauridae, both of which are named after the animal. The first specimen was found by farmer Marshall Parker Felch in 1883, and he excavated it over the course of the next year. Most of the skeleton was complete, including the skull. The fossil was discovered in Garden Park just outside of Canon City (now Cañon City), Colorado; it was shipped to the Peabody Museum of Natural History where it was examined and named by paleontologist Othniel Charles Marsh in 1884. At the time, it was the most complete theropod fossil discovered in the United States of America.

More Ceratosaurus remains would not be found until the 1960s. A specimen unearthed in Utah’s Cleveland-Lloyd Dinosaur Quarry proved to be among the largest of its kind; a sub-adult was eventually found near Fruita, Colorado in 1976 by Thor Erikson. In 2000, paleontologists suggested that the large specimen from Utah should belong to a new species C. dentisculatus while the smaller specimen from Colorado should likewise be classified as C. magnicornis. Not all modern paleontologists agree, suggesting instead that these two represent growth stages and not distinct species.

Some remains found outside of North America have also been attributed to Ceratosaurus. Some have been found in the Tendaguru Formation in Tanzania, and bones which may belong to this dinosaur have also been found in the Lourinhã Formation of Portugal. A single tooth found near Moutier, Switzerland may belong to Ceratosaurus as well.

At the end of the 20th century, International Genetic Technologies successfully cloned Ceratosaurus nasicornis on Isla Sorna. During this time, heavy restrictions on genetic engineering were in place through the Gene Guard Act, so the creation of this animal was in violation of the law. It is not known how much control Simon Masrani or Henry Wu had over this activity, or to what degree they were even aware of it. Due to improper management on the part of InGen, this dinosaur is believed to have become extinct.


Ceratosaurus is a medium-sized carnivorous theropod, easily distinguished by its vivid coloration and prominent nasal horn. Adults reach lengths of 30.5 feet and grow to be 12 feet tall, noticeably larger than currently-known fossil specimens (which reach lengths of 18.7 feet or 5.69 meters). They may weigh up to one ton. The skull is large for its body size, and its jaws are lined with a row of long blade-like teeth. When its mouth is closed, most of these teeth are hidden, but ten or more teeth in the the upper jaw protrude out of the mouth.

Detail on the face of an adult Ceratosaurus. Note that ten teeth of the upper jaw remain exposed when the mouth is shut.

The nasal horn is ridge-like and shaped like an equilateral triangle. It is not very sharp, and is roughly a foot tall in adults; it is much thinner from side to side, located on the midline of the snout. The skull of the animal also has small hornlets above its eyes, and small conical osteoderms on its crown. More elongated osteoderms continue in a row down the midline of the animal’s thick neck and all the way down its back to its tail, located above the neural spines. This feature is unique among theropods known in the fossil record. Its eyes are relatively small, with yellow-orange sclerae and circular black pupils. The nostrils are somewhat large, likely giving it a good sense of smell.

The body is overall fairly robust, with a thick neck and stocky chest. Even the tail is thick, tapering down to a small point. The arms are small, with four minute fingers on each hand; the legs are thicker and stronger, with three clawed toes on each foot. Its tail is deep from top to bottom, somewhat like a crocodile’s. Its body is more compact than fleet-footed theropods such as Allosaurus, with shorter legs and a low-built torso.

Coloration of the Ceratosaurus is, perhaps, one of its most striking features. The head is a vibrant shade of red, with some whitish stripes along the upper lips and slightly darker scales around the eyes. Starting around the neck and going all the way to the tail are gray or black irregular stripes, overlaying the animal’s base coloration. These are most vibrant on the neck, becoming gradually more faded toward the tail; they do not extend to the underbelly. The red coloration of the head also fades over the rest of the body, being replaced with a pale yellow color; its underbelly is even lighter, being almost white. On the tail, the gray stripes come closer together, eventually occupying more space than the light yellow base color.

Concept art by Shaun Keenan depicting a baby Ceratosaurus (top) alongside a Yutyrannus and Cryolophosaurus.

The hatchling stage has only been depicted in concept art. Like many baby animals, it has a proportionally large head, with its body being smaller by comparison. It lacks the distinctive coloration of the adult, and its nasal horn and osteoderms are less prominent at this stage. The teeth are smaller and less exposed.

One individual hatched in 1998 or 1999 had reached adulthood by 2001, meaning it grew from infancy to adulthood in two or three years. This was presumably achieved by the use of growth-enhancing supplements provided by Masrani Global Corporation personnel.

Sexual Dimorphism

Some Ceratosaurus are much duller in color than others, appearing mostly gray without the vibrant red and yellow markings, and only faded stripes. These less colorful animals are assumed to be the females, while the brightly-hued individuals are assumed to be male.

Preferred Habitat

This species has been sighted in heavily forested area and is generally seen near sources of water, where it drinks and finds its food. In the Jurassic period, this animal would have inhabited wetlands, lakes, and floodplains.

Muertes Archipelago

Sometime between late 1998 and mid-1999, Ceratosaurus was cloned on Isla Sorna by InGen under its new parent company Masrani Global Corporation. These animals were created in violation of the Gene Guard Act. Within nine months of their creation, they were abandoned to roam the island.

On the night of July 19, 2001, one adult Ceratosaurus was seen on the western bank of Isla Sorna’s central channel. Because of its bright colors, it is assumed to have been a male. It is not known how many animals, if there were more than one, existed on the island.

Known range of C. nasicornis on Isla Sorna as of July 19, 2001

The interference on Isla Sorna by Masrani Global Corporation caused an ecological collapse over the next five years, and in late 2004, any surviving Ceratosaurus were allegedly collected and transported to Isla Nublar. Since this animal favors water, it is possible that some swam to neighboring islands of the Muertes Archipelago from Isla Sorna, but none have ever been confirmed.

Isla Nublar

In late 2004, all surviving Ceratosaurus were allegedly transported from Isla Sorna to Isla Nublar. After a few weeks in a quarantine pen, each animal would be introduced to a habitat, presumably in Sector 5 away from the park proper. There is no evidence that this animal was ever intended for exhibition in Jurassic World.

This plain gray-colored Ceratosaurus is assumed to be the female of its species, since males are often more vibrant.

There were at least four Ceratosaurus living on the island as of 2015: two gray individuals assumed to be females, and two more brightly-colored animals assumed to be males. Due to the closure of Jurassic World in 2015, they were able to roam freely on the island. They were sighted in the vicinity of Camp Cretaceous in early 2016, and were known to frequent an upstream watering hole. By the coming of summer, they were known from the Gondola Lift area. In May or June 2016, one of the brighter-colored (most likely male) Ceratosaurus was ambushed and killed near the Gondola Lift by the theropod hybrid E750, a member of the Scorpios rex species. The other male survived this period of time and was sighted later in June in the northeast of the island. None of the remaining ceratosaurs have been seen since 2016.

A report released by the Dinosaur Protection Group on February 4, 2018 implied that Ceratosaurus had gone extinct on Isla Nublar.

Mantah Corp Island

Sometime before June 2016, Mantah Corporation was able to obtain at least one Ceratosaurus, either by capturing it live or cloning it from acquired genetic materials. In either case, it was obtained illegally from InGen assets. It has bright colors suggesting it is a male. The animal was an adult as of that date and was housed in a testing facility on Mantah Corp Island. At the time, it was in the medical bay being treated for injuries; its normal habitat is currently unknown. It does not appear to frequent the redwood forest biome, though it presumably still lives in the facility.

BioSyn Genetics Sanctuary

Although numerous dinosaur species entered the wild in 2018, no Ceratosaurus seem to have been among them. This means that when BioSyn Genetics was authorized to capture and contain de-extinct animals by various governments in the 2020s, only genetic samples of Ceratosaurus were probably around to acquire, and none are believe to have ever been housed in the BioSyn Genetics Sanctuary.

Black market

Dinosaur poaching in the Muertes Archipelago and near Isla Nublar was a problem between 1997 and 2018. As there is currently no list of species that are believed to have been poached, it is unknown if Ceratosaurus was among them. If DNA samples of this creature are on the black market, there is a strong chance they will turn up in the Amber Clave, the world’s most notorious hub of illegal de-extinction technology trade. Anyone with sufficient resources could restore Ceratosaurus to life again now that the technology has gone open-source.

Wild populations

Ceratosaurus was originally native to western Laurasia, namely the North American subcontinent (which, as Laurasia rifted apart, became its own continent). It evolved during the Jurassic period, about 153 million years ago, and existed for around five million years. The habitats it preferred seem to have included forests and wetlands, with distinct wet and dry seasons. Fragmentary fossil remains suggest that other species of Ceratosaurus may have lived in the parts of Laurasia that developed into Europe, as well as North America; its range may have included the islands that gave rise to Portugal and Switzerland. Some paleontologists also suggest that this genus had a presence in Gondwana to the south, particularly the developing African continent. About 148 million years ago, this dinosaur seems to have died out, probably due to changes in its environment that it could not adapt to quickly enough. Preserved DNA samples were recovered millions of years later by scientists who used them to reconstruct its genome using genetic engineering, which allowed them to clone new Ceratosaurus specimens.

Due to legal issues surrounding the creation of this species little is known about its population statistics. It is believed to have gone extinct in the wild at least twice, once on Isla Sorna between 2001 and 2004 and then on Isla Nublar between 2016 and 2018, but there is always the possibility that some survived. If any now live elsewhere in the world, they have yet to be reported to the Department of Prehistoric Wildlife.

Behavior and Ecology
Activity Patterns

Ceratosaurus is mainly active at night, coming out to hunt under cover of darkness. However, it is not nocturnal; during the daytime it patrols its territory, drinks, and bathes. This activity classifies it as cathermal.

Diet and Feeding Behavior

This dinosaur is carnivorous and hunts live prey. Its blade-like teeth are capable of inflicting injury to prey, but as the teeth in the very front of the mouth are the largest, it is less able to tear into larger prey items with its entire mouth. Instead, it probably delivers wounding bites and wait for its prey to weaken. Smaller prey is more easily killed, so it can probably make just one bite to take out a human-sized animal. It ambushes prey from the cover of forests, chasing it down until the prey is exhausted and then landing a fatal bite. While its jaws are not as strong as those of some other theropods, its speed and endurance are excellent, allowing it to hunt via pursuit. A crepuscular hunter, it has good senses that allow it to track prey in dim conditions.

Based on fossil evidence, Ceratosaurus is believed to have lived near bodies of water and may have been a skilled swimmer. This would allow it to prey on fish, turtles, and other aquatic life. On Isla Sorna, the river where this dinosaur was sighted was home to fish such as bonitos. The mobile game Jurassic Park: Builder describes this animal as being an excellent swimmer which feeds on fish and marine reptiles, suggesting that it may venture into shallow oceanic environments to search for food. It also happily feeds on terrestrial animals, nearly always those much smaller than itself, including baby dinosaurs. One has been seen attempting to feed on a two-month-old Brachiosaurus.

Video games have consistently portrayed it as feeding primarily on small to medium animals and carrion, as well as displaying cannibalistic tendencies in Jurassic Park: Operation Genesis. This game identifies the Ceratosaurus as being a generalist feeder, not being picky about its diet (though the game states that its favored prey is Dryosaurus, a species which was not cloned in the films). They are portrayed in the game as being capable of hunting in groups, but also solitary hunting. It is portrayed in Jurassic World: Evolution as having a large appetite for its size.

Social Behavior

These dinosaurs are usually solitary, preferring to travel alone. They mostly congregate near sources of water.

Its physical features indicate that it does engage in some degree of social interaction, as its striking pattern would make it poor at camouflaging and its nasal horn is not robust enough to serve any combative purpose. The mobile application Jurassic World Facts states that the horn, at least, serves as a display structure during courtship, but also states that this species is a lone hunter.


As a dinosaur, this animal lays eggs to reproduce. However, specific details about its reproductive behaviors are unknown. Its nasal horn, bright facial coloration, and elongated spinal osteoderms all indicate that it engages in some kind of display behavior, but the nature of such behaviors have not been observed. Other theropods are portrayed as having cloacae in Jurassic Park: The Game, suggesting that Ceratosaurus probably does as well.

Jurassic World Facts states that the horn plays a role in courtship displays, but does not go into detail on how it is used.

Theropod eggs are ovoid, like those of birds. This evolutionary trait discourages them from rolling away from where the parents place them. Ceratosaurus is a medium-sized theropod, so its eggs likely incubated for around six months before hatching.


Ceratosaurus has been heard to make low growling or gurgling noises when alone, and was heard making a groaning sound when frightened. Its nasal horn and bright colors are believed to have social functions, since they would not help it in other ways.

It is normally rather quiet, and is mainly heard making growls and other subtle noises. However, when agitated or being territorial, it can make louder roars. There are fairly few animals that it comes into conflict with; it backs down from most dangerous rivals, and seldom challenges other creatures. Therefore most of its vocalizations are not used for aggressive displays. It is more likely to make a louder confrontational roar if it feels threatened or upset.

Ecological Interactions
Ceratosaurus displaying a fear response

This animal was known to share some overlapping territory on Isla Sorna with the much larger Spinosaurus. On one occasion, a Ceratosaurus was seen smelling dung from a Spinosaurus and immediately retreating from the area, suggesting an antagonistic relationship between this animal and its larger, stronger, and more aggressive neighbor.

Though a predator, it can coexist relatively peacefully alongside many other dinosaur species. A few were known on Isla Nublar to frequent watering holes alongside herbivores such as Stegosaurus, SinoceratopsParasaurolophus, Brachiosaurus, and Ankylosaurus. Many of these well-armored and large dinosaurs would present a challenge for any hunter, and since it preys mainly on aquatic life, the Ceratosaurus likely poses the adults little threat. It can prey on juveniles, however. Carnivores known from the area were Pteranodon, Tyrannosaurus, Velociraptor, Baryonyx, and Compsognathus; however, aside from the tiny compies, Ceratosaurus was not observed alongside these animals. This implies that it avoids watering holes when potential rivals or threats are there. They have been sighted near Dimorphodon nesting grounds.

The relative docility of Certosaurus allows it to live peaceably alongside many other dinosaur species.

The genetically-modified hybrid Scorpios rex killed at least one of four known Ceratosaurus on Isla Nublar in 2016. Only two are believed to have been males, one of which was killed by the hybrid in late May or early June. This means that Scorpios rex may have significantly contributed to the local extinction of Ceratosaurus on Isla Nublar. What eventually became of the survivors is unknown, but they have not been seen since 2016. Only one living male was seen after the Scorpios attacks; it is unknown whether the females survived.

As with nearly all de-extinct species, InGen’s ability to extract its DNA would be reliant on the fact that hematophagous, or blood-drinking, parasites such as female mosquitoes fed upon the blood of this animal in the Jurassic period. It is not known whether hematophagous species from the modern day still use it as a host.

The video game Jurassic World: Evolution portrays it as preferring a solitary life with few other species nearby. It is a host to the bacterium Campylobacter, which can sometimes cause the animal to become sick with campylobacteriosis. This bacterium is common in modern birds, inhabiting up to 100% of some poultry.

Cultural Significance

With its distinctive head ornamentation, Ceratosaurus is an instantly recognizable theropod and its unique appearance has lent it to great popularity. While members of the general public may not immediately know its scientific name, they have absolutely seen it in films, television, museums, and books about dinosaurs. Smaller than Tyrannosaurus but with the horn on its nose giving it an appearance reminiscent of early Victorian depictions of dinosaurs, this animal has long been a mainstay of popular culture theropods.

In Captivity

When the animals of Isla Sorna were relocated to Isla Nublar between 2004 and 2005, Ceratosaurus was maintained in the northern region of the island outside of Jurassic World. It was held ostensibly as a future park attraction, but there is no evidence it was ever actually integrated into the park. Because of this, not much is known about how it tends to fare in captivity. A proper enclosure for it would need to include its preferred habitat, meaning forest and lots of fresh water. It is mainly a twilight hunter, but does move about during the day; this means that if it were exhibited, visitors would mostly see it in a non-confrontational mood. This would make it less exciting, but more manageable than many theropods.

As of 2016, a single Ceratosaurus was known in captivity. It was housed by Mantah Corp in a clandestine facility, having been obtained illegally (either by direct capture or by acquisition of genetic samples). The company was researching its behavior, but both the company President Daniel Kon and the facility’s executive director and engineer Kash Langford intended to control its behavior using technological means for entertainment purposes.


Ceratosaurus is evolutionarily interesting because of its unique bodily features, such as the nasal horn and osteoderms found in arrangements not seen in other dinosaurs. Fossils are well-known and some very good specimens have been reported from North America, including a juvenile found in 1999. Paleontologists have debated how many species of this dinosaur there are; as many as three have been proposed, but some believe that C. nasicornis is the only species and that the others represent different stages of its growth. Additionally, remains found in Europe and Africa have been suggested to be Ceratosaurus, but this classification is not widely accepted.

This dinosaur gives its name to the clade Ceratosauria, which are more primitive theropods of the lineage that includes present-day birds. Because of their primitive features, the ceratosaurs have provided paleontologists with valuable information about theropod evolution, clearly presenting anatomical traits that differentiate early and later theropod species. Along with this, the fossil remains found in North America have revealed that Ceratosaurus coexisted with other types of theropods in the same environment. This suggests that it fulfilled a different ecological niche than its neighboring predators, enabling them to live alongside one another. In ecology, this phenomenon is known as niche partitioning, and is seen in many species-rich environments.

When it was brought back from extinction, this species was used for research and development for a de-extinction theme park; while it is not known precisely what experiments were performed on Ceratosaurus, it is known that InGen tested growth-boosting supplements on their cloned specimens during the late 1990s. These technologies were later used in Jurassic World to accelerate the growth process of animals to maturity. Ceratosaurus was also studied by Mantah Corp scientist Dr. Mae Turner sometime prior to 2016, particularly its neurobiology and cognition. Though Dr. Turner was led to believe this was an effort to provide for the dinosaur’s needs, Mantah Corp executives actually intended to find ways to control its behavior for entertainment purposes. Ceratosaurus was utilized to test new technologies for this purpose.


Its existence was of concern to Masrani Global Corporation, as it was not on InGen’s species list and therefore was substantial evidence that InGen had violated the Gene Guard Act. The survivors of the incident on Isla Sorna in 2001 were silenced from speaking about this animal’s existence following their rescue. Along with three other genera of dinosaur, Ceratosaurus was used as evidence during the 2016 investigation by the United States Congress into violation of the Gene Guard Act by InGen. An anonymous hacker revealed in late 2015 during the inquiry into Jurassic World that these four dinosaur genera were created illegally between 1998 and 1999, and three months later, the US Congress announced that it was open to inquiry into violation of the Gene Guard Act.

This species may have already become extinct by the time of the Mount Sibo controversy in 2017-18, since only three individuals were known to be alive as of Jurassic World’s closure in 2015. Ceratosaurus was discussed by the Dinosaur Protection Group as one of the species significant to the investigation into InGen, as well as listing it among other animals housed on Isla Nublar. On this list, its name was printed in red similar to species that are known to have gone extinct, while all those confirmed to still be alive were printed in black. This suggests that, as of February 2018 when this list was released, Ceratosaurus had died out. The DPG focused on animal rights aspects of these issues, describing acts of cruelty perpetrated against the dinosaurs during both the illegal cloning operations and the abandonment of Isla Nublar.

Ceratosaurus has only been confirmed alive in a Mantah Corp facility after June 2016, with the current status of the sole individual being unknown. It was subject to abuse at the orders of director Kash Langford, who was himself trying to fulfill the wishes of his boss Daniel Kon. The dinosaur was used to test technologies meant to control animal behavior.


Although the instantly-recognizable profile of this dinosaur and its fairly laid-back behavior patterns would make it an ideal candidate for de-extinction theme parks, it has yet to be tested in this capacity. In addition, it certainly would have been a source of unique biopharmaceutical products, but as it has most likely died out, these cannot be sampled.

The main use of Ceratosaurus as a resource was in the courtroom: it was used as evidence that InGen had illegally cloned new species of de-extinct life during a time when this was outlawed by the Gene Guard Act. It was also used as a test subject for new scientific processes, including growth acceleration and direct brain stimulation. The former was successful; the latter failed due to the maturity of the specimen used.


Ceratosaurus is, perhaps, one of the least aggressive carnivorous dinosaurs, and has so far only been implicated in one unprovoked attack on humans. This does not mean it is safe: knowing how to react if you encounter one is still important. Firstly, be aware of when it hunts; this is when it is more likely to be aggressive. Ceratosaurus chiefly hunts during twilight or at night, when visibility is lower. It may track you by scent or sound. Like with other carnivores, do not carry around food (especially fish or meat) in its territory, since this could attract it. Disguise your scent if you can. If you know there are Ceratosaurus in the area, travel during the daytime, when it is more likely to act docile. It is also less aggressive around sources of fresh water. During the 2001 incident on Isla Sorna, a group led by Dr. Alan Grant was able to avoid conflict with a Ceratosaurus through a combination of non-confrontational behavior and the use of Spinosaurus dung. Since the encounter happened near water, the ceratosaur was being investigative rather than hunting, and Dr. Grant’s group avoided provoking the animal. Finally, the smell of a larger and more dominant predator discouraged it from becoming aggressive. Tactics similar to these can help you stay safe.

The good news is that if you spot a Ceratosaurus, there is a strong chance it is not aggressive at the moment. It ambushes prey from the cover of forests, so if it is hunting it will try and sneak up on you. The fact that it has allowed you to see it means that it is probably not hunting you. Instead, it might be investigating something unfamiliar in its territory, determining whether or not you are a threat. If this is the case, remain calm and allow it to observe you until it is satisfied that you are not dangerous. Back away slowly and quietly; do not run. The Ceratosaurus will not expend energy in fighting or chasing something it does not need to, and will leave you alone if it sees no reason to instigate a conflict.

If you are attacked, fight back. Use whatever objects you can as weapons to batter its face, and strike at its nose or eyes. Bites can be countered by attacking the inside of its mouth or throat, which might encourage it to drop you. Of course, you will want to avoid bite wounds since these can lead to blood loss and later infections; to drive it away, you will want to startle it. Since it hunts at twilight and at night, sudden bright lights can surprise and temporarily blind it. Use tools such as flares or flashlights. If it becomes disoriented, it may give up the chase. You may also try to intimidate it, since it is not the apex predator in its environment and is perpetually wary of more dominant carnivores.

Behind the Scenes

It was originally thought that the CGI model of the Ceratosaurus resembled that of the Tyrannosaurus, and as a result the Ceratosaurus was speculated to be a mutant by some members of the Jurassic fandom. Such fans, including some progenitors to this Encyclopedia project, classified this animal as Ceratosaurus “mutatus” (x Tyrannosaurus rex); it was suggested that InGen may have filled in the gaps in the Ceratosaurus genome with tyrannosaur DNA. However, this was entirely speculative and is considered inaccurate now, as the Ceratosaurus from the Jurassic Park /// dinosaur charts demonstrates otherwise. We therefore believe that the animal in the film can indeed be classified as Ceratosaurus nasicornis.

In the original script for Jurassic Park ///, the characters would have encountered a Carnotaurus during this scene instead. Unlike the Ceratosaurus, this animal acted aggressively toward the humans and was only repelled by the smell of spinosaur dung. Ceratosaurus would not reappear on-screen until Season 2 of Jurassic World: Camp Cretaceous, in which it was the first dinosaur made for the show without the use of a preexisting Stan Winston Studios model. It was the first creature in the program that had not been previously featured in the Jurassic World film trilogy.

Disambiguation Links

Ceratosaurus nasicornis (IDW-JPR)

Ceratosaurus nasicornis (L/M)