Indominus rex was a very large genetically-engineered theropod dinosaur created by Dr. Henry Wu in 2012 and named by International Genetic Technologies. It was intended to be one of the upcoming attractions in Jurassic World on Isla Nublar. Its name means “fierce” or “untamable king,” and the name was intended to be scary and yet easy for children to pronounce. On the park website, the animal carries a danger rating of “Very High.” It was due to be displayed in the theme park in May 2015, but the actual date at which it would be put on display changed multiple times due to management issues stemming from its unpredictable nature.
According to the mobile game Jurassic World Alive, this genus (along with its descendant Indoraptor) are classified in the family Chimeridae. It should be noted that this family is fictional, and should not be confused with the factual family Chimaeridae.
Indominus rex was the most advanced hybrid genus engineered at the time. Its genome was constructed by inserting genes from various species into a template. Most of its constituent sources have been disclosed:
- Tyrannosaurus rex: The genome of this animal was used as a template into which genes could be inserted. This was the only constituent part on public record, though the Jurassic World website identifies several abelisaurs and one carcharodontosaur which were also used in creating the genome.
- Velociraptor antirrhopus: Genes from InGen’s Velociraptor were used to control development of the animal’s brain. This gave it heightened cognitive abilities and an instinctual comprehension of Velociraptor vocalizations, though this second effect may have been unintentional. Quills on the animal may have come from Velociraptor structural genes, but there is no confirmation of this.
- Carnotaurus sastrei: Structural genes from this abelisaur were inserted into the Indominus genome in order to facilitate the development of supraorbital horns and osteoderms on the body.
- Pycnonemosaurus nevesi: Structural genes from this abelisaur were inserted into the Indominus genome in order to facilitate the development of supraorbital horns and osteoderms on the body.
- Quilmesaurus curriei: Structural genes from this abelisaur were inserted into the Indominus genome in order to facilitate the development of supraorbital horns and osteoderms on the body.
- Viavenator exxoni: Structural genes from this abelisaur were inserted into the Indominus genome in order to facilitate the development of supraorbital horns and osteoderms on the body.
- Majungasaurus crenatissimus: Structural genes from this abelisaur were inserted into the Indominus genome in order to facilitate the development of supraorbital horns and osteoderms on the body.
- Rugops primus: Structural genes from this abelisaur were inserted into the Indominus genome in order to facilitate the development of supraorbital horns and osteoderms on the body.
- Giganotosaurus carolinii: Structural genes from this carcharodontosaur were inserted into the Indominus genome in order to facilitate the development of supraorbital horns and osteoderms on the body. The exceptional size of the resultant animal may have been related to regulatory genes from this species.
- Therizinosaurus cheloniformis: Structural genes from this therizinosaur were inserted into the Indominus genome in order to facilitate the development of lengthy and powerful front limbs, including large talons on the digits of these limbs.
- Deinosuchus rugosus: Structural genes from this alligatoroid were inserted into the Indominus genome to adjust the morphology of its dentition. This resulted in a total of 74 teeth with a combination of theropod and alligatoroid features; its teeth measure an average of 25 centimeters (9.8 inches).
- Sepiida: An unknown species of cuttlefish was sourced to allow the Indominus to survive an expedited growth rate. Genes from the cuttlefish controlling the development of chromatophores also integrated into the Indominus genome, resulting in an animal capable of advanced camouflage. Whether this was intentional on the part of its creators is unknown, but a holographic display featured in 2018 does detail its camouflage ability. According to Jurassic World: Evolution, the species of cuttlefish utilized for this purpose was Sepia officinalis, the European common cuttlefish.
- Neobatrachia: An unknown species of tree frog was sourced for genes to allow the Indominus to modulate its infrared output, which was intended to help it survive in a tropical climate. This also enabled it to avoid detection by hiding its thermal signature from surveillance, a behavior which it could utilize due to its ability to detect its own infrared radiation. The icon used on the official chart is the outline of Agalychnis callidryas, the red-eyed tree frog, but whether this is the actual species sourced has not been confirmed.
- Crotalinae: An unknown species of pit viper was sourced for genes to develop organs used for detecting infrared radiation. The Indominus possesses cranial cavities similar to the loreal fossae used by pit vipers. When combined with the ability to modulate its own thermal output, the Indominus could easily determine when it had successfully hidden itself from thermal sensing security devices. It is unlikely that this specific behavior was intended by Dr. Henry Wu, based on his surprised reaction. Genes from Crotalinae species may also have resulted in the ability to distend the jaw to an angle greater than ninety degrees by facilitating the development of highly kinetic quadrate and squamosal joints found in some snakes. The official chart refers to the snake as a “pit adder,” which is not a specific species. Rather, various types of snakes (mostly in the family Viperidae) are referred to as adders.
- Tetrapoda: Structural genes were sourced from a species which is still undisclosed in order to facilitate the development of opposable thumbs in the Indominus. The only known animals with true opposable thumbs include various species of mammals, particularly primates, and the frog genus Phyllomedusa. Other animals, such as chameleons and some theropod dinosaurs, have partially-opposable thumbs.
Indominus rex displays features from a wide range of animals, due to the structural genes sourced from many different species. Its head clearly shows influence from abelisaurid and carcharodontosaurid species, with its small, conical supraorbital horns and decorative osteoderms in particular coming from its abelisaurid heritage. The skull shape is determined by the tyrannosaur and carcharodontosaur genes in its genome; the teeth, of which there are 74, are altered in appearance due to the inclusion of alligatoroid DNA. The subadult seen in the film displays a number of damaged or broken teeth jutting out at various angles. Its teeth measure 25 centimeters (9.8 inches) on average, and are continuously replaced throughout its life as with most theropods. There appear to be more teeth in the lower jaw than the upper jaw, and the teeth at the front of the lower jaw tend to jut outward and create a basket-like appearance of the lower jaw. The jaws are long and relatively narrow, capable of distending to a very wide angle in a manner similar to snakes. On its face, the skin appears pulled tight, making the skeletal features plainly outlined; this includes cavities similar to the loreal fossae used by pit vipers to detect thermal radiation. Gray-colored quills appear on top of its head. The nostrils are quite large, similar to those of Tyrannosaurus, and the eyes are forward-facing with orange sclerae and black slit pupils. To protect its eyes, the Indominus has thick, transparent nictitating membranes which originate from the medial canthus of each eye. It has a comparatively short triangular pink tongue, which is not long enough to reach the lips.
Osteoderms cover much of the animal’s body, giving it decent protection against most attacks. These osteoderms are visible on the neck and back regions, but its scaly skin is quite thick everywhere, making the Indominus almost impenetrable. Its most noticeable anatomical feature, aside from its enormous jaws, are its forelimbs. Engineered with structural genes from Therizinosaurus, these arms are long enough to allow this animal to walk on four limbs or to crawl if it needs to. The hands are pronated, which is a common phenotypic error in all InGen’s theropods, but this feature actually benefits the Indominus as they enable it to get a grip on the ground. Each hand has four digits, including one opposable thumb and three much longer fingers. All four end in large talons. The arms are extremely muscular, and like the head, they bear long, gray-colored quills.
The legs of Indominus are also very powerful, and end in three-toed feet which also have large talons on them. It was capable of running at thirty miles per hour when in a confined area. While it is a facultative quadruped, the Indominus walks bipedally when in a hurry, unlike its descendant Indoraptor. Its tail is lengthy, but fairly nondescript. According to Dr. Henry Wu, the architect of the Indominus genome, the animal could reach fifty feet in length, making it the second-largest theropod known after Spinosaurus; however, his longest-lived specimen only survived until early adulthood and never reached its full size. A 2019 social media post by Universal Studios has given a 16.9-meter (55.4-foot) length for this animal, as well as a height of 6.7 meters (22 feet). Weight estimates are hard to come by, but at least one size chart suggests that it would reach 12,000 pounds at full size. This would make the animal larger than, but lighter in weight than, a healthy mature female Tyrannosaurus rex. The Jurassic World Hybrids children’s book lists its weight as six US short tons, which is equal to 12,000 pounds or 5,443.1 kilograms.
Among some of the more spectacular features of the Indominus is its skin. While it typically rests at a white coloration, chromatophores in the skin of the animal allow it to change the color of its body at will (excepting, of course, features such as its teeth or eyes). It appears to even have a layer of chromatophore-bearing tissue over some of its osteoderms, enabling it to hide more efficiently. The chromatophores would be similar to those found in cuttlefish, as this is the genetic source of this feature in Indominus. In addition, it is able to modulate its infrared output, and can actually determine when it has successfully lowered its body temperature to an undetectable level due to being able to sense infrared radiation using cranial cavities similar to the loreal fossae found in crotaline snakes.
The hatchling stage of Indominus rex is poorly known and few details have been disclosed. However, it is known that the claws are already fully-developed at the point of hatching, as they are used to break the eggshell. The skin appears to be slightly grayish and pinkish, but whether this is a fundamental feature or affected by the animal’s chromatophores is unknown. The eyes are disproportionately large for its skull size, which is normal in many baby animals, and there is no sign of horns or quills as in the mature animal. Body proportions, from what has been documented, appear similar to hatchling Velociraptor.
A young Indominus can be created in the mobile game Jurassic Park Builder; it more or less resembles a smaller version of the adult, with a proportionally larger head.
Older juvenile or adolescent stages have not been observed. Fully-grown adults have also not been observed, due to the fact that neither specimen survived until adulthood; only the hatchling and subadult stages are known. However, Henry Wu’s confidence that the Indominus was ready for exhibition suggests that the adult and subadult differ in few ways other than sheer size.
Adulthood is reached in three or four years. According to InGen’s Senior Assets Manager Claire Dearing, this growth rate exceeded their expectations.
Male Indominus have never been created. Thus, any sexual dimorphism is unknown.
Due to its being artificially created, the preferred habitat of Indominus rex is unconfirmed. However, one in Jurassic World regularly favored forested areas after it escaped Paddock 11. There is no way to determine if this preference for forest was due to the habitat of its paddock, which was densely packed with trees, or because forest cover allowed it to camouflage more effectively.
The game Jurassic World: Evolution portrays the Indominus requiring 23,100 square meters of grassland and 7,500 square meters of forest in its territory.
In 2012, two female I. rex were hatched in the Hammond Creation Laboratory after several years of design and engineering by Dr. Henry Wu. These would be the first and only members of their species bred on the island.
Sometime prior to 2014, the Indominus were moved to Paddock 11, a specialized holding facility located in the northwest region of Isla Nublar. They would remain here until their attraction was completed.
One of the two specimens was cannibalized by its sibling prior to November 2014.
On December 18, 2015, the surviving Indominus escaped confinement due to a combination of corporate mismanagement and the secrecy and corruption surrounding the animal’s eventual purpose. The Indominus traveled southeast across the island, retreating north again after park security attempted to subdue it. Late that night, park staff collaborated in a complicated and highly risky plan to kill the animal, culminating in it being ambushed and killed by the park’s resident Mosasaurus. This incident resulted in the extinction of Indominus rex, and as the park was closed down and Henry Wu’s assets seized by the US government very shortly after the incident, no more of this animal could be created.
There is no evidence of Indominus rex ever being introduced to Isla Sorna.
Indominus rex has, to the extent of current knowledge, only ever lived on Isla Nublar. InGen Security removed the remaining specimens from Dr. Wu’s laboratory during the 2015 incident, but much of his material (including all I. rex genetic material) was seized by the United States government shortly thereafter. What was eventually done with this genetic material, or what entity currently has control of it, is not known.
Behavior and Ecology
Because it is an artificial creation, the activity patterns of Indominus rex are poorly researched. It has been known to be active at all times of day or night, though it was likely active primarily during the day when it was in captivity, as this is when its keepers would have brought it food.
The mobile game Jurassic Park: Builder portrays the Indominus as being active for eight-hour intervals, while that game’s sequel Jurassic World: The Game has the animal active for twelve-hour periods of time instead.
Diet and Feeding Behavior
Indominus rex is a carnivore. Its natural diet is unknown, due to it being an artificial creation; only one was ever allowed into the wild, and it did not survive for a full day. While in captivity, it was fed prepared meat from cattle. In a deleted scene, Katashi Hamada explained that the animal could not be given live food, as this could lead to the animal only wanting live food from then on.
This species is not above cannibalism, as one of the two specimens killed and ate its sibling sometime after they hatched. The motivation for the attack is unknown, but it would have likely been the first instance of an Indominus killing and eating prey. However, there is no record of what caused this incident; the kill may have been due to territorial, rather than predatory, behavior. If this is the case, it is likely that Indominus would also eat the carcasses of territorial rivals it had killed.
As soon as it was presented with the opportunity, however, the Indominus did take live food in the form of two InGen employees. Previously, it had nearly severed the arm of at least one handler during feeding time, indicating a strong desire to attack live prey even earlier than this. In a deleted scene, Owen Grady and Claire Dearing find a pile of dung which the junior novelization identifies as Indominus droppings, but it is not known what meal these droppings were from; at a minimum, it means that this animal digests its meals in a few hours.
Once outside of containment, the animal was not seen to actively eat its victims, instead engaging in surplus killing. According to Owen Grady, these surplus killings were performed out of enjoyment rather than a predatory nature. Victims of the Indominus included several ACU personnel including Katashi Hamada, at least one Timack Construction employee, six Apatosaurus, one Ankylosaurus, and two Velociraptor. The animal also attempted to attack multiple Pteranodons in the Jurassic World Aviary, but failed to kill any; it ignored the smaller Dimorphodons.
The Indominus primarily uses its large jaws to kill prey and other victims, typically clamping smaller prey items around the midsection to instantly kill them. When facing larger targets than itself, this animal will bring its massive clawed arms into play, hooking its talons in to tear at exposed flesh or wildly swinging its arms around to create deep lacerations that lead to death by trauma and blood loss. It can also distend its jaws to wrap around larger victims. Its high intelligence allows it to be inventive in combat, learning new strategies and studying its victims to discern their weaknesses. For example, when combating an Ankylosaurus, the Indominus discovered that its jaws could not pierce the dorsal armor of its victim; it was able to use its claws to tear at the ankylosaur’s left rear leg, toppling the herbivore. The Indominus then pushed it onto its back, planted a foot on its victim’s belly, and bit into its neck to kill it.
Its jaws and teeth are powerful enough to puncture the aluminum oxynitride glass exterior of a gyrosphere, which was supposedly able to withstand a twenty-two caliber bullet. There is, however, strong evidence that the gyrosphere’s exterior was not as resilient as Masrani Global Corporation claimed it to be.
When handling smaller food items, the Indominus uses its hands to grasp its victims. It may then toss its victim to wound or kill it, or it may simply bite off chunks. Despite its enormous mouth, it usually does not swallow prey whole.
If prey items manage to escape, an Indominus may choose to wait in place to see if they accidentally reveal themselves again. The Indominus which had chased Zach and Gray Mitchell waited for roughly seventeen seconds after they escaped into a small pond, giving up when they did not resurface quickly enough.
Only two of this animal were ever created, so the full extent of their social behaviors cannot be determined. At some point before the species was first hinted at in November 2014, one of the specimens had killed and cannibalized the other, leaving just one.
The game Jurassic World: Evolution also portrays the Indominus as a solitary animal which does not tolerate other members of its own species in its territory.
Indominus is, however, known to socialize with Velociraptor antirrhopus so long as the raptors behave in a subordinate manner. At the first sign of competition for dominance, the Indominus will attempt to kill its competitor.
No Indominus have ever reproduced naturally, as no males have ever existed. The two which hatched in 2012 were documented at the time, however, and details of their hatching behavior is fairly well recorded. The incubation period is presumed to be between three and six months, based on the relatively small size of the hatchlings.
Prior to hatching, the dinosaurs’ heartbeats were at around sixty beats per minute. Using its clawed hand, the hatchling broke through the upper part of the eggshell, pushing away shell fragments and tapping on the egg’s exterior in a nervous manner. It made a grasping motion with its hand, fingers visibly shaking. At this point, the heartbeats of both eggs began to speed up, suggesting that the sounds of the first hatchling were audible to the second and provoked a response. The second hatchling could be seen pushing its eggshell from the inside, failing to break it open immediately, while making a cooing sound. Meanwhile, the first hatchling cleared away enough eggshell to peer out of the egg. Its pupil was already extremely narrow, despite not having been exposed to any bright light before hatching. It could be heard making quiet hissing and growling noises. They received no assistance from their human caretakers during hatching, performing the act entirely on their own.
It is unknown how Indominus would go about mating and breeding, or if this artificial organism would be capable of reproduction at all. Both Tyrannosaurus and Velociraptor are portrayed with cloacae in Jurassic Park: The Game, so it is most likely that Indominus would have a cloaca to house its reproductive organs as well.
According to the Jurassic Intel website, Indominus eggs are not particularly large, suggesting that the surviving female laid unfertilized eggs during its time in Jurassic World. Theropod eggs are generally oblong.
The vocal sounds of the Indominus were largely territorial in nature, as there were no other members of its species in existence following the death of one specimen via cannibalism. The volume of its roars have been measured at 140 to 160 decibels. It can be heard making snarling, growling, and roaring sounds more or less at random, but it makes particularly loud roars when it is about to start chasing a victim. It is known to pursue victims even when it is not hungry, so these vocalizations (which would be counterproductive if it were hunting for food) may be a means by which to make victims flee so that it can entertain itself chasing them. Similar behavior has been observed in Tyrannosaurus, which chases smaller animals as a form of play.
Some aspects of its physiology allow it to make noises similar to those of other species. It is capable of some rudimentary communication with Velociraptor antirrhopus, including throaty barks and gargling noises which are used to establish dominance and vocalize commands. It can also make a weaker version of the distinctive ringing bellow used by Tyrannosaurus rex to confront territorial rivals. As it has not been observed in the wild extensively, communication with other genetic sources such as Carnotaurus is not yet confirmed.
When frustrated, the Indominus can be heard screeching loudly.
Although it rarely socializes, some degree of body language is known in Indominus. When behaving aggressively, it gapes its jaw to show its teeth and mouth. It has been seen to assume body postures similar to the animals it is interacting with, notably Velociraptor. For example, while the arms are normally extended, Indominus may tuck them closer to its body when socializing with Velociraptors and raise its head higher. These raptor-like mannerisms help it establish itself as a dominant figure to these other animals.
There is no known natural ecology for Indominus rex, as it is an artificially-engineered species.
When the one surviving specimen entered the wild, it was immensely destructive to its habitat as it engaged in excessive surplus killing. It was confirmed to have killed six Apatosaurus by lacerating them on the hips, chests, flanks, shoulders, and necks. It also killed one Ankylosaurus by biting its throat after overturning the animal. Later it was seen to behave aggressively toward Pteranodons, but was unable to kill any, and at one point threatened a Troodon but also was unable to make a kill. During scuffles with some of its victims, it destroyed local plant life due to its large size. The only species to really benefit from its presence are scavengers, such as birds seen feeding on the Apatosaurus carcasses.
The only intentional positive interaction the Indominus was shown to engage in was with four genetically-modified Velociraptors. Recognizing them as something similar to itself, the hybrid established some rudimentary communication with the raptors and formed a mutual symbiotic relationship with them. The raptors were smaller and thus more stealthy and agile than the Indominus, allowing them to pick off InGen Security personnel more easily; meanwhile, the sheer size and power of the Indominus would in theory protect the raptors. This relationship proved to be inherently unstable, however, as the Indominus could not tolerate any challenge to its authority. One of the Velociraptors, an individual named Blue, refused to kill Owen Grady due to her familial connection to the human who had raised her from infancy. The Indominus then became enraged and attempted to kill Blue, which turned the remaining raptors against the hybrid dinosaur. It proceeded to kill them.
Indominus rex was seen to engage in combat with a female Tyrannosaurus rex, though in this case the tyrannosaur instigated the fight for territorial purposes. The Indominus likely would have been the victor, but due to complicated circumstances, was instead forced into a corner where it was preyed upon by a Mosasaurus.
What was left of its skeleton eventually became a habitat for sessile marine life and small fish.
The game Jurassic World: Evolution depicts the Indominus as becoming stressed if there are more than a handful of animals in its environment, lashing out violently as soon as it feels too crowded. It is also portrayed as being host to the bacterium Campylobacter, which in real life can be found in up to 100% of some bird populations and is a common pathogen in many theropods in the game. This microorganism can cause campylobacteriosis.
Relationship to Humans
All of the interactions Indominus has been seen to engage in with humans have been negative, and many were violent. It was maintained in a relatively small paddock for an animal of its size, with little to no stimulation for an animal with its level of intelligence. Animal behaviorist Owen Grady concluded that the only positive relationship it had was with the crane that delivered its food (a necessary precaution, due to the fact that the animal could predict where feeders were going to deliver food from and would attack them). Due to the subpar conditions in which this particular animal was raised, it is unknown if this violent behavior toward humans was instinctual or learned, or if it would be universal across any Indominus.
The creation of the Indominus was authorized by Simon Masrani and Claire Dearing on April 4, 2008 after a unanimous decision of the Board of Directors that Jurassic World needed a new attraction to boost attendance. Over the next four years, Dr. Henry Wu would work with InGen’s genetics division to engineer this animal, with his only instruction being that the animal be “cooler” than anything they had created before. At some point during the development process, head of InGen Security Vic Hoskins approached Dr. Wu with a proposition on behalf of Eli Mills to make Indominus combat-oriented and suitable for use by military organizations; in exchange, Wu’s research would be funded by Mills. Wu accepted the offer.
Simon Masrani revealed the animal’s existence to the public in January of 2015 on his corporate blog after hinting about it for several months. He himself would not actually see it until his repeatedly-delayed visit on December 18 of that year. It was marketed with the tagline “Bigger. Louder. More Teeth.” After its public reveal, online ticket purchases to Jurassic World skyrocketed. Ironically, this same animal would later force Jurassic World to close due to bad publicity following a series of incidents it caused across Isla Nublar.
Ultimately, the Indominus proved unfit for military applications due to its violently aggressive behavior. Hoskins had proposed creating smaller versions of the animal, hopefully making them more suitable to accept the training regimen which had already been proven effective with Velociraptors. The result was the creation of the Indoraptor.
Based on Jurassic World: Evolution, the cost of raising an Indominus from fertilization to maturity as of 2018 would be $2,516,000.
Behind the Scenes
In earlier stages of development, this animal went under the name “Diabolus rex,” meaning “devil king” or “king of devils.” It went through several design variants, including one which featured a larger set of fang-like teeth and one which highlighted its carcharodontosaurian traits.
Another earlier version of Jurassic World would have featured this animal as a newly-discovered but naturally-occurring dinosaur species found in China; director Colin Trevorrow disagreed with this decision and instead pushed for Indominus to be an artificially-created creature. This ultimately makes more sense, as the park had been creating dinosaurs for upwards of ten years at that point and should not, reasonably, fail simply because another new creature was discovered. Furthermore, featuring the Indominus as a “real” dinosaur found by paleontologists would likely confuse audiences. Finally, the theme of the franchise overall is that attempting to control nature inevitably leads to harm; the Indominus being an attempt to manipulate nature is more thematically appropriate than it being a natural animal which, for no particular reason, can destroy the park.
Some aspects of its anatomy and genetics were designed directly by the filmmakers, whereas other aspects were suggested by contributors. For example, the idea of its lanky arms being the result of Therizinosaurus genes was suggested by Dr. Jack Horner.