Dilophosaurus “venenifer” (*) (S/F) / (S/F-T/G)

Disambiguation Links – Dilophosaurus “venenifer” (SF-Ride)

Dilophosaurus, with a name meaning “double-crested reptile,” is a small to medium-sized species of theropod dinosaur in the family Dilophosauridae. It lived 193 million years ago, during the Sinemurian stage of the Early Jurassic. Three skeletons of this animal were discovered in the Kayenta Formation of Navajo County, Arizona in 1940, and two skeletons of excellent quality were found by Jesse Williams in 1942. Paleontologist Samuel P. Welles named it Megalosaurus wetherilli in 1954; the specific epithet honors Navajo councilor John Wetherill. In 1964, a more complete skeleton was discovered, including the skull. With the signature pair of crests now known to science, Welles assigned this species to a new genus, Dilophosaurus, in 1970.

The family to which this animal belongs, Dilophosauridae, includes a number of early theropods such as Cryolophosaurus, Dracovenator, and Zupaysaurus. Fossils of Dilophosaurus include specimens of varying completeness and ages; at least one fossil consisting of scattered fragments is believed to come from an infant. Fossilized footprints have been attributed to Dilophosaurus, giving some insight into how it moved.

There is currently only one known species of Dilophosaurus in the fossil record. A second species, Dilophosaurus sinensis, was named in 1993, but was later found to be the same as a previously-known species called Sinosaurus triassicus.

International Genetic Technologies succeeded in cloning Dilophosaurus from prehistoric amber sometime between 1991 and 1993. The specimens InGen created possess an atypically large number of phenotypic anomalies, believed to be a result of gene splicing. While the InGen IntraNet website identifies the specimens as D. wetherilli, Jurassic-Pedia has assigned a new specific epithet to distinguish InGen’s specimens from those known from the fossil record. InGen specimens are classified herein as Dilophosaurus venenifer, the specific epithet meaning “venom-bearing.” In common parlance, D. venenifer are sometimes referred to as “spitters” or “dilos.”

Jurassic Park: The Game implies that this species contains genetic structures from Hyperolius viridiflavus in its genome. However, it is officially confirmed to contain donor genes from Dendrobates leucomelas which integrated successfully. It is not impossible that differing lineages of InGen Dilophosaurus may have had one or both of these frog species hybridized into their genomes, but it is more likely that the eggs seen in the game were unfertilized and the implication that the animal was made with H. viridiflavus DNA is incorrect. As of June 11, 1993, InGen had created up to Version 2.01 of this species.

Description
Juvenile and projected adult size of D. venenifer

Dilophosaurus reached a length of 6 meters (20 feet) in adulthood, with a hip height of around 1.8 meters (6 feet) and a weight of 454 kilograms (1,000 pounds). This makes it a small or medium-sized theropod, but for the time period in which it lived, it was quite large. Around half its length consists of its lengthy, somewhat flexible tail. All parts of its body are slender, giving it a build suited for agile movement. However, D. venenifer is slightly smaller and heavier than D. wetherilli, which can reach 7 meters (23 feet) in length and is estimated to weigh around 400 kilograms (880 pounds).

It has strong legs, with very large thigh bones and long, stout feet. Three of the toes bear large claws, with the first toe (or hallux) being much smaller and raised off the ground. All of these features give it a considerable running speed of 30 miles per hour, and enable it to travel with an unusual hopping gait as well as more conventional running. Like nearly all theropods, it is a biped. Dilophosaurus is very nimble due to its lightweight frame and strong legs.

The arms of this dinosaur are lanky but strong, like its legs. The hands have four digits, including an opposable thumb. The thumb is short, but bears a powerful claw; the next two fingers are longer and thinner, with smaller claws. Its fourth finger is vestigial, serving no functional purpose; this appears to have been lost entirely in D. venenifer. Its arms are designed for grasping; along with the feet, they are used for capturing prey. The wrists of this theropod are pronated, like most InGen theropod specimens but unlike those in the fossil record.

Of course, the most distinctive feature of this dinosaur is its skull, placed on the end of a relatively long and slender neck. Dilophosaurus is characterized by its pair of thin plate-shaped lateral crests, which form a V-shape when viewed from the front. They are semicircular, each with a small pointed prong on the back, and constitute about half the height of the skull; they are larger in D. venenifer than in fossil specimens of D. wetherilli. The jaws are large, filled with thirty sharp, serrated teeth. Larger teeth are situated in the back, with smaller ones at the front. These are not as robust as in later, larger theropods, but are not as fragile as commonly assumed; they would be replaced throughout life. Its upper jaw possessed a gap or “kink” just below the nostril, which is smaller in D. venenifer than in fossils, but not absent. The jaws are narrow in the front and wider in the back. The tongue is large and triangular, with a purplish color, and the nostrils and eyes both face forward.

Juvenile D. venenifer with cowl extended in an aggressive display

Several anatomical features are present on the head of D. venenifer which are not known from any fossil specimens. These include an extendable cowl or frill around the neck similar to that of the frill-necked lizard (Chlamydosaurus kingii), which is supported by cartilaginous rods attached to the neck. This normally lies retracted flat against the neck, but can be unfurled by the animal and flushed with color. When unfurled, the cowl has a diameter that easily more than triples the width of the head, and bears a serrated edge. Muscles on the throat permit the cowl to be vibrated when extended. A second feature of D. venenifer not present in D. wetherilli is a set of venom glands; while some concept art portrays these as being located underneath the lower jaw, their actual placement is not known. Dark-colored venom is squeezed out from underneath the tongue and expelled at high speed from the mouth, striking with reasonable accuracy at distances of fifteen to twenty feet (up to six meters). While soft-tissue features such as these would not fossilize, Dr. Laura Sorkin as well as multiple accessory sources indicate that the cowl and venom glands are an unintended result of genetic engineering. These include a queue video from the Jurassic World ride, in which Dr. Henry Wu himself confirms that the abnormal features are unintended results of genetic engineering.

Dilophosaurus diorama in Benjamin Lockwood’s estate. The coloration may be indicative of a prior version of the animal.

Dilophosaurus features cryptic coloration, meaning it is suited for camouflage. It inhabits forested areas, and thus has a body which is forest green in color with darker green splotches on the back, legs, and crests. Alternative depictions have shown it with reddish-brown splotches, rather than dark green ones. The cowl is brilliantly colored; when flushed with color it appears bright yellow with intricate red patterning. Alternative depictions show a yellow-gray cowl color with a solid red-brown ring around each flap of the cowl. Unused shots of the holoscape display in Jurassic World show an image of a Dilophosaurus that is a plain light woody brown color over its whole body, while a diorama at Benjamin Lockwood’s estate shows a solid green dilophosaur with a bright red cowl and crests. No living dilophosaurs have been seen with either color variant, but it is not unreasonable to assume that some exist or existed with these.

Growth

Four-foot tall juvenile Dilophosaurus have been observed in the flesh, while digital renditions of adults have been seen. A hologram of an adult dilophosaur in the Samsung Innovation Center shows an animal that, while approximately twenty feet in length, has essentially the same proportions as the juveniles.

Hatchlings have never been observed in the film-canon, but one is depicted in the mobile game Jurassic Park: Builder. It has similar proportions to the adult, but the head is proportionally larger and the crests smaller. The cowl does not develop until maturity. It is not known if the film canon proper includes this same development procedure for the cowl.

The growth rate of Dilophosaurus is something of a mystery. While InGen documentation does demonstrate that the animal should reach its full twenty-foot length, numerous sources associated with the original film claim that the juvenile size is as large as it gets. This includes Dr. Laura Sorkin’s notes, wherein she claims that Dr. Henry Wu’s genetic engineering is likely the reason for their small size. However, within the same canon source as Dr. Sorkin’s journals, the Tour The Island site includes a video which shows the full size of the dilophosaur as twenty feet and states that those in the Park are currently juveniles. The reason for this internal discrepancy is not known, and it has been suggested that the dilophosaurs did not grow as rapidly as they were expected to.

Sexual Dimorphism

While no sexual dimorphism has been observed directly, it is mentioned in concept art for the films; the male appears to be larger, more brightly colored, and with taller crests and a larger cowl.

Jurassic Park: The Game implies that genetically modified Dilophosaurus cloned by InGen may be capable of protogyny. As of such, an animal which outwardly appears female may actually have male reproductive organs, assuming that the eggs witnessed in the game were fertilized and that this animal’s genome does contain Hyperolius viridiflavus DNA. If these eggs were unfertilized and the genome contains only Dendrobates leucomelas DNA, it is incapable of protogyny.

Habitat
Preferred Habitat

Dilophosaurus appears to prefer forested habitat. It has been sighted in heavily forested areas, and all three of its known paddocks in the original Park include large amounts of trees, shrubs, and undergrowth. They may nest in such regions, and are known to venture into upland areas.

Fossil evidence suggests that they prefer to remain near sources of water. The mobile application Jurassic World Facts states the same, implying that the cloned dilophosaurs may have similar habitat preferences to their fossil ancestors.

These animals are nomadic, and therefore can adapt to multiple kinds of environment. They travel along with their food sources.

The game Jurassic World: Evolution portrays the Dilophosaurus as requiring 9,800 square meters of forest and 9,800 square meters of grassland in its territory.

Isla Nublar

Three dilophosaur paddocks existed in the original Jurassic Park on Isla Nublar. The primary paddock, located to the west of the paddock areas, is the only one confirmed to house any dilophosaurs prior to the incident. As this species was cloned between 1991 and 1993, all animals were juveniles at the time. The primary paddock included a reasonably sized stream as well as dense forest, and bordered the main tour road to the northeast separated by a five-foot electric fence. To the southwest, it bordered a service road, also separated by a five-foot electric fence. To the west, it bordered the perimeter fence, and to the south, it bordered a twenty-four-foot-tall electric fence that separated it from what would have eventually become the Proceratosaurus paddock.

The secondary dilophosaur paddock was located farther north, near the central mountains of the island. It bordered the main tour road to the northwest, separated from it by a five-foot electric fence and also heavily forested. On all its other boundaries, it was separated from other animal paddocks by the twenty-four-foot electric fence; to the east was the primary Triceratops paddock, and to the south was the primary herbivore paddock containing both Brachiosaurus and Parasaurolophus. No animals are known to have been housed here, though plans were presumably in place.

The tertiary dilophosaur paddock was located much farther east. While there was signage on the roads leading to the paddock to warn employees and visitors of the animal, none are confirmed to have been housed there at the time of the incident. This paddock was likely similar to the others in terms of ecology. It was separated from what would have been the Baryonyx paddock by the main tour road, with a five-foot-tall electric fence on the dilophosaurs’ side. The tour road was present on the eastern and southern sides of this paddock. On its other borders, the twenty-four-foot paddock fences separated it from the tyrannosaur paddock to the north and the original Velociraptor paddock (later intended to be the Herrerasaurus paddock) to the west. It has been suggested that, due to the rapidity with which dilophosaurs appeared in this area during the incident, that some were already present here, but there is no direct evidence to support this claim.

All of the dilophosaurs on Isla Nublar as of 1993 were assumed to be females, but the presence of eggs found during the incident suggests that at least one may have become a male.

Populated (red), planned (orange), and hypothetically-populated (purple) paddocks for D. venenifer on Isla Nublar (prior to June 11, 1993)

On June 11, 1993, the Park’s power grid was sabotaged by a disgruntled employee, permitting the animals to leave their paddocks. Within minutes, one of the juvenile Dilophosaurus was present near the East Dock, someplace south of the tertiary paddock. A broken egg, presumed to belong to a dilophosaur, was found in the immediate vicinity. Some minutes after that, a group of five dilophosaurs including the original was present in that area; one was killed when it was struck by a vehicle, and the remainder fled when driven away by Troodons.

A sixth dilophosaur was observed nesting between the Western Ridge and Bone Shaker on June 12. Its nest contained four eggs, one of which was unintentionally destroyed by the rescue operation taking place on the island. Footprints potentially belonging to Dilophosaurus were found in the Western Ridge, but they differ in morphology from known dilophosaur prints. These may have instead belonged to Herrerasaurus, which had a similar range at the time.

In October 1994, InGen surveyed the island to assess the animal populations. The five remaining Dilophosaurus were found to still be alive and had remained as a cohesive unit; the lack of any new animals indicates that their eggs did not survive. They did not settle in any particular location and appeared to be nomadic, roaming around the island.

Known or highly suspected (red) and hypothetical (purple) range of D. venenifer on Isla Nublar (following June 11, 1993). Note that the hypothetical range may be broader than shown here; regions of the island that are mostly unknown are not included.

Dilophosaurus survived in the wild on the island until InGen returned to reclaim it in 2002. It is possible that some dilophosaurs may have been shipped to Isla Sorna during construction; however, according to Simon Masrani, there were dilophosaurs living in contained areas of the island as of August 2004. Because very few dinosaurs had yet been returned to the island, and no carnivores had been shipped over yet, this means that at least some dilophosaurs remained on Isla Nublar during the entire construction period. They likely remained in the north of the island.

Throughout the final months of Jurassic World‘s construction, beginning after September 2004 and ending sometime before the park’s opening date at the end of May 2005, the remaining Dilophosaurus from Isla Sorna were shipped to Isla Nublar. Following a period of isolation in the quarantine paddocks, they would have been integrated into habitats in Sector 5. They most likely remained there for the ten-year duration of Jurassic World’s operation.

Despite it not being exhibited in Jurassic World, the park still sought to educate visitors about the animal.

No dilophosaurs are known to have been exhibited in Jurassic World. However, the aluminum oxynitride glass of the gyrospheres was specifically said to be a defensive measure against Dilophosaurus, which suggests that the animals escaped captivity and entered the central valley frequently enough to merit mentioning to visitors in the safety video. Alternatively, dilophosaurs may have been exhibited at some point in the past and were removed for safety concerns or other reasons.

According to Jurassic World: Evolution, the tyrannosaur was the only animal from the original Park still on the island by the time of the 2015 incident. While this contradicts statements made by film director J.A. Bayona, it would imply that none of the original dilophosaurs were still alive by that time.

Following the island’s abandonment after December 18, 2015, the dilophosaurs would have been able to roam freely over the island. It is unknown how many existed on the island for this period of time. At an unknown day in June 2016, at least one dilophosaur was heard near Main Street, suggesting that some lived in that area. Scrapped concepts for Jurassic World: Fallen Kingdom imply that several Dilophosaurus still inhabited central or northern Isla Nublar; it is unknown whether they would have been featured on Main Street, near the radio bunker, or elsewhere in the vicinity of Mount Sibo. However, an image released by the Dinosaur Protection Group on February 4, 2018 confirmed that Dilophosaurus still lived on the island at that time.

On June 23, 2018, Mount Sibo erupted violently and caused massive ecological and physical damage to Isla Nublar. Any Dilophosaurus surviving after the eruption would have suffered a loss of food sources and forest habitat, potentially leading to their extinction. A deleted scene for the film would have shown that at least two dilophosaurs were removed from Isla Nublar by means of the S.S. Arcadia.

Isla Sorna

InGen cloned Dilophosaurus on Isla Sorna sometime following September 20, 1991, at which point Dr. Wu was still perfecting the genome. It is not known where on Isla Sorna the dilophosaurs lived, though John Hammond later asserted that the carnivores chiefly kept to the island’s interior regions. As this animal preys upon fish and other small animals, it probably kept somewhat near Isla Sorna’s many tidal inlets and rivers.

At the last count before InGen stopped monitoring Isla Sorna in 1993, there were twelve Dilophosaurus confirmed living on the island.

Hypothetical range of D. venenifer on Isla Sorna between 1993 and 2004. Note that the actual range may be significantly different, as this is conjecture based on a statement by John Hammond.

By 2004, Isla Sorna had suffered a catastrophic population crash due to a sudden influx of animals cloned there illegally in late 1998 and early 1999. The decrease in population was also impacted by poaching. Beginning in September 2004 at the earliest, InGen under the wing of Masrani Global Corporation began removing the surviving animals from Isla Sorna and delivering them to Isla Nublar, where they remained.

Other

It is not known if any Dilophosaurus were removed from Isla Sorna or Isla Nublar by poachers, though reports of gruesome injuries to collectors on the mainland suggest that it is possible.

A deleted scene in Jurassic World: Fallen Kingdom would have revealed that at least two dilophosaurs were removed from Isla Nublar on June 23, 2018 by means of the S.S. Arcadia, which would have delivered the animal to Benjamin Lockwood‘s estate near Orick, California. Their fate, if they were indeed removed, remains unknown; they may have been sold, escaped, or died during the incident.

Behavior and Ecology
Daily Activity

Dilophosaurus is nocturnal, meaning it is predominantly active at night.

In the mobile game Jurassic Park: Builder, the Dilophosaurus is active for fifteen-minute intervals at a time. In the sequel Jurassic World: The Game, it is instead active for half an hour at a time.

Diet and Feeding Behavior

A carnivore, Dilophosaurus feeds predominantly on fish and small dinosaurs, which it captures by ambush. It then uses its strong legs and grasping hands to grapple with prey items and force them into submission. It does not generally use its jaws to kill prey; its teeth are narrower than those of later theropods, and its frame more lightweight. Still, even a juvenile dilophosaur can use its strength and agility to take down human-sized prey with great efficiency.

The feature that makes Dilophosaurus such an efficient predator is its venom. While venom is common in reptiles such as snakes, it is fairly rare in dinosaurs, and Dilophosaurus is the only one known to spit its venom. It uses both sight and smell to locate prey, and once it has accurately gauged its prey’s location, the animal will forcibly expel a fairly large quantity of thick, sticky venom at its target. It will typically aim for the eyes. The venom can cause severe damage to the eyes of the victim, potentially leading to blindness and thus disorientation. If left alone, the venom can lead to full-body paralysis. Once a prey item is hit, the dilophosaur will often wait for the venom to take effect before moving in for the kill. Prey may be eaten alive once paralysis sets in, or left for later.

Dilophosaurus has a range of predatory adaptations including strong limbs, social intelligence, agility, and venom which it can spit at prey.

While a solitary dilophosaur is a formidable predator in its own right, these animals are at their most fearsome when operating in groups. The hunting group’s leader will mark the prey item with its venomous expulsion, which disorients the prey. Communicating using both visual and vocal cues, the group will then corral the prey, attempting to corner it someplace where it is vulnerable. While the alpha is the one which initiates the attack by spitting venom, any of the dilophosaurs may use their venom to incapacitate the prey. The neck cowl may also be brought into play, being used to surprise and frighten the victim into making a misstep. Dilophosaur packs have even been known to target small groups of prey, splitting into teams to take down two prey items simultaneously. These modestly intelligent carnivores are able to strategize efficiently and are tenacious hunters, rarely giving up the chase until they manage to make a kill.

In the game Jurassic Park: Operation Genesis, the favored prey of Dilophosaurus is said to be the ornithopod Dryosaurus; however, this animal has not been cloned by InGen in the film canon. Its diet likely included the Nublar tufted deer and feral goats, as well as small dinosaurs such as Microceratus and Compsognathus; all of these animals are known to live in similar habitats.

Social Behavior

Most Dilophosaurus are social animals, preferring to live in small groups called herds or packs. These groups have defined hierarchies, somewhat like family groups; a leader or alpha is in charge of hunting, and is the one to initiate an attack by spitting venom at the intended prey item. The others follow the alpha’s lead. These animals are highly vocal with one another and have a complex communication system; they also use their cowls and crests to display to members of their own species, though it is currently unknown how much individualistic variation exists among the patterns on these structures. While the clones would have been visually and genetically identical to others of the same version number, their descendants may have been more individualistic, especially in a naturally-social species.

The InGen IntraNet website describes dilophosaurs as having a sophisticated social life, with apparent rules and manners surrounding resting, breeding, and hunting. However, there are some individuals that prefer a solitary life and travel alone.

Jurassic World: Evolution portrays the dilophosaur as being comfortable alone or in groups of up to twelve animals. Like in the film, the animal uses both visual and auditory cues to communicate, and will often socialize with its own kind. Gregarious behavior in dilophosaurs has been consistently portrayed in various other video games based on the films.

Reproduction

All dinosaurs lay eggs to reproduce, and the dilophosaur is no different. Courtship displays involve the use of the cowl, as well as the head crests; these are the dilophosaur’s most noticeable features, and the only parts of its body not designed for camouflage. Scrapped concepts for the first film suggest that the male’s size and brightness of cowl color are factors in determining whether a female will mate with him.

Cloaca of a Dilophosaurus as portrayed in Jurassic Park: The Game

While it is unconfirmed, some fans have suggested that the yellow hooded raincoat worn by Dennis Nedry during the 1993 incident resembled a male dilophosaur’s cowl closely enough to attract the attention of a female dilophosaur. If true, this would be in line with the idea that the cowl is used in mating displays by the male.

Dilophosaurus reaches sexual maturity long before it reaches skeletal maturity, so it is able to breed when it is much less than full-sized. During the 1993 incident, eggs were found to have been laid by dilophosaurs that were around five feet long, or a quarter of their maximum size. Both the male and female have a cloaca, which houses the sex organs.

The nests are scraped together using earth and other debris, but the eggs are left uncovered; this suggests that the adult broods them like a bird. The eggs are round and somewhat large, a few inches in diameter, and are white and gray. A juvenile mother dilophosaur may lay around four eggs in a clutch and guard them fiercely. However, the remainder of the social group may leave her alone to hunt some miles from the nesting site; this may be to avoid drawing attention to the nest’s location. Dilophosaur parents have been known to abandon their eggs if a great enough threat is present, and on occasion, they may lay eggs outside of the nest and abandon them there. Presumably, the full-sized adult would be capable of laying more eggs than the juvenile owing to being larger.

Dilophosaurus nest, Isla Nublar (6/12/1993)

Smaller theropods usually have incubation periods lasting between three and six months, and the dilophosaur being on the lower end of the size scale means that it would likely have a shorter incubation period. It is unknown how long the parents care for their offspring; adolescents are capable of fending for themselves, so they do not need parental care to survive at this stage.

Vocalizations

Among the theropods, perhaps only Velociraptor is known to have a more diverse and complex system of communication than Dilophosaurus. This animal produces a wide variety of cries that have been compared to monkeys, birds, and other creatures; it possesses surprisingly advanced vocal organs, similar to those of the modern whooping crane (Grus americana).

Because relatively little observation into Dilophosaurus social life has been described or shown, their vocalizations are still not entirely understood. However, the general meanings of many of the sounds they make are fairly clear. When confronting an unfamiliar animal, a dilophosaur can be heard making trilling and chirping sounds; these have been interpreted as indicating uncertainty, curiosity, or sociability. Hooting sounds are almost universally indicative of arousal or anticipation and are often followed by more aggressive behavior. These hooting sounds can easily be mistaken by a human to indicate friendliness, but are actually signs of mounting excitement in the animal. More rapid hooting and chirping can be heard from an angry individual; the rapidity and frequency of the vocalizations appears to distinguish between anticipation and anger.

During hunts and other aggressive behaviors, the animal can be heard growling, snarling, and hissing; some of these sounds serve to frighten the prey into movement, but they presumably also serve to communicate among the pack when multiple dilophosaurs hunt together. For example, a very specific hissing sound immediately precedes a venom-spitting attack, which would allow one dilophosaur to alert its packmates to its impending action. When the cowl is extended, it can be shaken to produce a rattling sound, which draws attention to the animal. This cowl-rattling may be used for signalling or intimidation.

Dilophosaurus also uses visual cues to communicate. The cowl is the most obvious example; it is used to intimidate rivals, signal to potential mates, and engage in other social behaviors. During pack hunts, Dilophosaurus will frequently flare its cowl when confronting prey. This often causes the prey to freeze in surprise or change course. When one dilophosaur flares its cowl at a running prey item, it not only signals to its fellows where the prey is, but also attempts to redirect the prey. Dilophosaurs likely pay attention to the flaring behavior of their hunting partners as a means of communicating how best to corral and incapacitate the prey.

Dilophosaurus curiously approaching an unfamiliar figure. Note the cowl, which can be seen folded against the neck with its color drained. When initiating a confrontation, the cowl is unfurled and flushed with color.

In addition to communicating with one another, the aggressive displays of Dilophosaurus also can be used for interspecific communication. For example, the cowl is flared at competitors and predators when the dilophosaur is confronted. This can be seen as a kind of honest signalling, indicating to the predator that the dilophosaur is healthy and able to fight back. By shaking its cowl to produce a rattling sound, as well as hissing, the dilophosaur can advertise its status as a threat to animals nearby and discourage them from preying on it. These techniques are also used on prey; the sudden appearance of a colorful cowl and surprising noise will often cause the prey to look directly at the dilophosaur, giving it an easy shot at the prey’s eyes. From here, the dilophosaur will continue to use visual and vocal displays to confuse and disorient prey, causing the prey to stumble and fall while it attempts to flee. The dilophosaur can then easily wait in ambush for the prey to blunder into a vulnerable state.

Jurassic World: Evolution includes most of these vocalizations and visual displays in the animal, and also gives it more social behaviors. When socializing, the dilophosaurs will make cawing and rasping sounds.

Ecological Interactions

The Dilophosaurus is one of InGen’s most successful predators, owing to its multiple adaptations (both naturally-occurring and as a result of gene splicing). It is mostly a small-game hunter, but is adept at efficiently killing prey while also avoiding predators. Between the 1993 incident and 1994 island assessment, Dilophosaurus was one of only two dinosaurs whose population was not found to have decreased. The other was Tyrannosaurus, which had a population of one animal.

It is known to prey on fish and small dinosaurs. Compsognathus are known to inhabit the same territory as Dilophosaurus; compy footprints were sighted around a dilophosaur nest during the 1993 incident, though it is not known if the compies were actively attempting to prey on the eggs. Herrerasaurus inhabited a nearby area, and Tyrannosaurus and Pteranodon were likewise sighted nearby. In particular, the huge territories claimed by Tyrannosaurus would mean that a group of dilophosaurs might migrate over some considerable distance and still remain within a tyrannosaur’s territory. Modern animals, including birds such as the collared aracari (Pteroglossus torquatus) and Franklin’s gull (Leucophaeus pipixcan), are known to have inhabited the same territory as Dilophosaurus and would have been potential prey items.

Because of their preference for water and diet including fish, there is a good chance this small theropod would have competed with spinosaurs such as Baryonyx, Suchomimus, and Spinosaurus for space and food. Here, its venom would give it an advantage over these much larger and brawnier piscivores. Pterosaurs such as Pteranodon and Dimorphodon would also be potential competitors. These pterosaurs were found near the Jurassic World Lagoon between late 2015 and the summer of 2018, an area that dilophosaurs were known to inhabit as of 2016.

On Isla Nublar, Dilophosaurus was known to venture into the central valley, which was home to a great number of considerably larger animals. These would be vastly outside of a dilophosaur’s prey range, excepting perhaps Gallimimus; it is more likely that the forest-loving and reclusive Dilophosaurus would avoid the open plains where the huge herbivores roamed.

Benjamin Lockwood’s estate includes a diorama depicting a confrontation between two juvenile D. venenifer and an adult male Velociraptor antirrhopus nublarensis, but no confrontations between these species have been recorded. While they are tenacious predators, Dilophosaurus will back down from Troodon pectinodon. They will avoid confrontation with this species and give it a wide berth, as most animals do.

It is not without parasites and pests. The folds of its cowl provide ample surface area for microorganisms to grow on, and if not kept clean and dry, the cowl could become infected with parasitic fungi. A dilophosaur with a fungal infection in its cowl would have a hard time hiding this health defect from its peers, and as the cowl is essential in the mating display, it would be unlikely to attract a mate in such a condition.

In Jurassic World: Evolution, the Dilophosaurus is uncomfortable with large populations of other species near itself and prefers to live among its own kind. It is particularly susceptible to parasitic hookworm infections.

Interactions with Humans

Dilophosaurus was intended to be exhibited in Jurassic Park, with three separate locations where it would be visible along the main tour road. Guests were to be advised to keep their windows rolled up while passing through these areas, though; employees likewise would have to wear eye protection when working with Dilophosaurus. In spite of this, John Hammond was clearly pleased with how this species had turned out and placed it first on the Jurassic Park tour.

Less pleased with the animal was Dr. Laura Sorkin, who blamed Dr. Henry Wu‘s genetic engineering techniques for the multiple phenotypic anomalies exhibited by Dilophosaurus. In many ways, the animal is sometimes seen as emblematic of the “shortcuts” taken by Dr. Wu when engineering de-extinct life, along with Velociraptor.

In actual practice, Dilophosaurus made a poor Park attraction due to its nocturnal nature and cryptic coloration. It did not make an appearance when the endorsement tour occurred, though they did escape confinement in the ensuing incident. Two deaths have been attributed to Dilophosaurus as a result of the incident. However, this animal is fairly elusive and rarely encountered.

DILOHOLO
Hologram of an adult Dilophosaurus in the Samsung Innovation Center

Perhaps due to lessons learned during the original Park’s operation, it does not appear that any attempts were made to exhibit this animal in Jurassic World at any point. It did sometimes escape its habitat in Sector 5, escaping into Gyrosphere Valley where it could encounter guests. Dilophosaurus has nowhere near the strength needed to break into a gyrosphere, but nonetheless, guests were reassured in the gyrosphere safety video that Dilophosaurus venom could not penetrate the aluminum oxynitride glass. Dilophosaurus was also featured on the holoscape in the Innovation Center.

The potential applications of Dilophosaurus and its venomous spit did not go unnoticed by people seeking to exploit them, however. In 2018, at least two Dilophosaurus may have been collected by Ken Wheatley at the behest of Eli Mills; it is unknown if any were successfully brought to auction, and if so, what became of them.

Based on Jurassic World: Evolution, the cost of raising a Dilophosaurus from fertilization to maturity as of 2018 would be $317,000.

Behind the Scenes

The unusual features of the film’s Dilophosaurus, including its extendable cowl and comparatively small size, were added to help viewers tell the difference between the Dilophosaurus and Velociraptor. Its venom is the only unusual feature that was originally a part of its depiction in the novel upon which the film is based; the idea of Dilophosaurus incapacitating its prey with venom is based on an older interpretation of its teeth being too fragile for biting.

In media associated with the first film, such as some of the trading cards, Dilophosaurus is said to only reach five or six feet in length. However, as early as 1997, the idea of the animal from the film being a juvenile had taken hold and its size was listed as 20 feet long.

Despite attempts to explain the animal’s abnormal features through genetic engineering and growth stages, the general public (and a fair number of video game studios) have interpreted Jurassic Park‘s dilophosaur as an accurate representation, which it is not. Perhaps in an attempt to avoid criticism from the paleontological community, the filmmakers have avoided featuring the animal since the first film; it was planned to appear in 2018’s Jurassic World: Fallen Kingdom, but was ultimately cut, with any existing footage never to be released.