Dimorphodon is a medium-sized species of pterosaur that first originated in the early-to-mid-Jurassic Period, 195 to 190 million years ago. The name Dimorphodon translates to “two-form tooth.” This refers to the animal’s two different varieties of teeth, a trait that is rare among reptiles. Its specific epithet macronyx means “large claw,” referring to the size of the claws on its hands. Discovered at Lyme Regis in the United Kingdom (now a World Heritage Site, known as the “Jurassic Coast”) in 1828 by fossil collector Mary Anning, Dimorphodon was originally classified under the genus Pterodactylus. It would later be reclassified by Richard Owen in 1858 after discovering its skull. Remains of this genus are rare, but some have been identified from Aust Cliff in southwestern England.
A second, larger species of Dimorphodon was discovered in 1998 in Huizachal Canyon at La Boca Formation, northeastern Mexico. It was named Dimorphodon weintraubi by its discoverer James Clark; the specific epithet here is intended to honor Dr. Robert L. Weintraub.
International Genetic Technologies succeeded in obtaining DNA from Dimorphodon prior to 1993, but the viability rate of the species was at 36% at the time of the incident due to the genome’s incomplete status. Over a decade later, InGen’s new parent company Masrani Global Corporation completed the genome and was able to clone the animal. The species cloned by InGen is presumed to be D. macronyx because it is slightly more common and better-known, and more tentatively because D. weintraubi was not discovered until after InGen identified its Dimorphodon DNA. The Jurassic World website does mention Dimorphodon as being found in both England and Mexico, however, and there are instances of InGen referring to species such as Suchomimus that, in real life, had not yet been discovered at the time the documents were written. It is also possible that, like InGen’s Velociraptor, gene splicing techniques and poor record-keeping have resulted in today’s Dimorphodons potentially containing DNA from both fossil species.
Compared to InGen’s other pterosaur species, Pteranodon, the Dimorphodon is comparatively small. It grows to 2.3 meters (8ft) long including the tail, weighing around three pounds. When standing on its hind legs, it is about 3.2 feet tall; despite being winged, it walks with a quadruped gait, as its legs are not built for running. Its wingspan is about 4.6 feet. Dimorphodon‘s wings are not as powerful as those of more advanced pterosaurs; rather than lengthy bouts of powered flight or gliding, this creature is suited to short, frantic flights. It is also known to ride in the wakes of larger pterosaurs and aircraft to conserve energy.
Dimorphodon‘s most striking feature is its large head, which appears disproportionate for its body size and is unusually boxy in shape. The skull shape of the genetically-engineered specimens created by Masrani Global Corporation is more rectangular than fossil specimens, which were still quite bulky but with a rounded snout. In fossil specimens, there are five fang-like teeth in the front of each jaw, which are absent in those cloned by InGen, followed by thirty to forty small, narrow sharp teeth. The de-extinct specimens have mouths entirely full of long, needle-like teeth, a marked difference from the unique dentition of the original animal.
The skull is lightened by large apertures in the bone, which are plainly visible on InGen’s Dimorphodons due to the “shrink-wrapped” appearance of their skin (a feature which is almost certainly the result of genetic engineering, rather than the animal’s natural appearance). Another feature present on InGen’s specimens, but not those known from fossils, is the presence of large supraorbital ridges like those seen on some theropod dinosaurs. These can be observed over the eyes, which are relatively large and possess round pupils and yellow sclerae. The musculature of the jaws is quite advanced, allowing the Dimorphodon to execute rapid snapping bites. However, its bite force is weak, and the teeth do not penetrate very deep. It has a relatively long, thin, pointed tongue, which cannot extend out of the mouth.
Like all pterosaurs, the wings of Dimorphodon are supported by the fourth finger of the hand, which is greatly elongated. The membrane of the wing, called the patagium, is divided into two parts: the propatagium, which extends from the shoulder to the wrist, and the brachiopatagium, which extends from the fourth finger to the leg.
Dimorphodon possesses quite powerful limbs and large curved claws on its wings and feet, which enable it to climb excellently. It is depicted doing so in the mobile game Jurassic World: The Game, which shows the pterosaur as able to climb trees with a saltatorial gait rather like a squirrel. It is also shown to be capable of brief bipedal running, using its wings for stability; however, it walks on all fours virtually all the time. It is built with a low center of gravity, which further enhances its climbing ability.
Unlike the pterodactyloid pterosaurs, Dimorphodon possesses a lengthy tail which may be longer than the rest of the body. Its tail consists of thirty vertebrae, and terminates in a rudder-like structure which is presumably used for steering during its brief moments of flight. Its tail is left free, rather than being connected to the wings or legs by patagia.
Coloration of this species is variable but generally dark. Most are gray, but may have tints of blue; others appear pale green, while some are closer to black. The wings, generally, are lighter-colored than the body, and it is common for the face to have pink tints. Darker stripes may be present on the back, and the snout may have a dark pinkish-gray stripe as well as reddish skin around the eyes.
On the dorsal side, Dimorphodon has a coating of pycnofibers (a type of structure analogous to hair or feathers) which presumably assist with retaining heat. Due to animation or modeling constraints, they are depicted with bare skin in Jurassic World: Camp Cretaceous.
Individuals of varying sizes have been observed, but the animal’s growth rate is not known. Smaller, and thus presumably younger, Dimorphodons have generally narrower jaws and lighter build, but appear proportionally similar to the older animals. Pterosaurs in general are believed to have been fully capable of flight shortly after hatching, and so would not have undergone a great many physical changes during maturation.
As of now, there is no way to accurately sex a Dimorphodon. The sexes are externally indistinguishable from one another, and so can only be identified through invasive observation.
Jurassic World’s staff housed Dimorphodon in an aviary with numerous cliffs, trees, and shallow rivers. The structure had an area of 430,000 square feet. However, personnel cited by the Dinosaur Protection Group after the 2015 Isla Nublar incident suggested that these conditions were inadequate for the animals, and that they would need a larger body of water in their habitat as well as more living space. During the incident, they instinctively flocked to the nearest large body of water, the Jurassic World Lagoon, suggesting that they tolerate salt water.
Sometime between 2005 and 2014, Masrani Global Corporation cloned Dimorphodon macronyx, housing the species in the Jurassic World Aviary on Isla Nublar. On December 22, 2015, at least 43 Dimorphodon were observed on the island.
During the incident of December 22, 2015, the pterosaurs were frightened out of the aviary due to a combination of a break-in by the escaped Indominus rex and subsequent vehicular accident. They followed the larger Pteranodons westward, then turning to the southeast to approach Sector 3. Upon arriving there, they established Main Street and the Boardwalk as hunting and nesting territory. During the incident, multiple animals were tranquilized in mid-flight; at least seven died due to internal injury or drowning in the Lagoon after being sedated. An eighth presumably died due to an overdose of tranquilizers delivered by Senior Assets Manager Claire Dearing during the incident.
At least one individual reached the island’s eastern coast, but was gunned down by InGen Security while flying alongside a helicopter.
The flock had established breeding grounds at Lookout Point, a section of the Gondola Lift in the Western Ridge, by June 2016. At least four or five nests with three eggs each were seen. Unfortunately, these nests were all destroyed in a massive gasoline explosion which obliterated the mountaintop that month. Since the explosion occurred at night, some of the adults may have been away feeding, but many were probably still at the nesting ground and were killed. This was a devastating blow to Isla Nublar’s Dimorphodon population from which they would never recover.
No Dimorphodons were encountered during the June 23, 2018 mission. A poster released in February 2017 by the Dinosaur Protection Group implied that Dimorphodon was extant at the time, presumably in regions of the island not extensively surveyed during the incident. It is not known how many, if any, Dimorphodon survived the eruption of Mount Sibo on June 23.
While InGen’s operations originally took place on Isla Sorna, the viability of Dimorphodon was insufficient to clone any at the time. It is not known whether any migrated to this island following their release from the Jurassic World Aviary.
An original native of the Laramidian continent, this pterosaur evolved approximately 195 million years ago during the early Jurassic period. At the time, the supercontinent of Pangaea had just recently begun to break apart. Most fossils of Dimorphodon are known from Europe, in what is now southern England; however, the species D. weintraubi is native to what is now southern North America (remains were discovered in eastern Mexico). This suggests that species of Dimorphodon ranged across northern Laramidia even as the continent rifted apart. It became extinct around 190 million years ago due to changes in its environment; like most prehistoric species, the exact circumstances are hard to determine. It was restored to life through genetic engineering in the early twenty-first century.
Dimorphodon has been shown to have the instinct to flock toward large saltwater bodies, and at least one attempted to leave Isla Nublar on December 22, 2015. It is not known if any others have attempted to leave the island since, or if they have succeeded. If any did leave the island and survive the overseas journey, they would most likely have settled elsewhere in Central America.
Behavior and Ecology
While this reptile has been observed as active during the day, the Jurassic World website’s advertisement for the Romance Package describes them as being vocal at night. This suggests that the animals are normally crepuscular or nocturnal, which their large eyes also suggest; they may socialize in the evening or at night. Interference from their artificial environment may have encouraged cathermal behavior patterns; visitors and staff likely caused the Dimorphodons to be active intermittently throughout the day, as did their diurnal neighbors the Pteranodons. In the wild, they appear to roost in trees during the daytime and emerge only when disturbed.
Diet and Feeding Behavior
As a carnivore, the Dimorphodon feeds mainly on small animals. Insects and fish constitute a large amount of its diet; this suggests that it feeds low to the ground. Its jaws are not designed for puncturing flesh, but rather for entrapping prey; it uses its excellent eyesight to locate a food item, then quickly closes its jaws around the victim. The long claws of the toes may also be used to help capture prey. Its quick, biting attacks have led to it being characterized as a “snap-feeder.”
However, these animals can also act in large swarms to overwhelm groups of prey that they could not take down on their own. They have been observed engaging in feeding frenzies alongside Pteranodon; both genera of pterosaur will frighten and disorient groups of prey by dive-bombing, making loud vocalizations, and knocking debris around. While the prey items are panicked and confused, the pterosaurs will pick off the most vulnerable prey. Dimorphodons may tackle larger prey feet-first to knock them over, pull them off of ledges if they try to escape by climbing, and bite vulnerable areas. Because of the weak jaws of the Dimorphodon, it relies on a preliminary physical attack to incapacitate larger prey before biting. Its snout is surprisingly resilient, and it is capable of delivering a moderate headbutt in flight without injuring itself. When pinning down larger prey, it may beat its wings to maintain balance and disorient the prey.
Such feeding frenzies are presumed to be rare events, though. Typically, Dimorphodon cannot kill prey larger than itself. In fact, a feeding frenzy of this type has only been observed once, and is believed to have been caused by stress and understimulation in both pterosaur species involved.
While Dimorphodon are moderately aggressive toward most other species, they are actually quite gregarious among themselves. Even after leaving the confines of the Jurassic World Aviary, the Isla Nublar flock remained mostly close together as it journeyed across the island. Feeding and nesting are done communally, and the pterosaurs are highly vocal with one another. They will rally to defend their nesting grounds if predators threaten the eggs. Despite this, they are not known to interact with each other physically, maintaining a sense of personal space.
On occasion, Dimorphodon may venture away from the flock, and appear to have no discomfort about being on their own in unfamiliar territory.
As with all pterosaurs, Dimorphodon lay eggs, and most likely have cloacae which are used to mate. Eggs appear to be laid by June, during what would be the rainy season in Costa Rica. Nests are scratched into the ground and marked using small rocks and other natural debris, located at high altitudes where predators cannot easily reach. They appear to prefer open ground with limited nearby shelter for nesting sites. Eggs are slightly ovoid and large for a reptile this size, barely smaller than a human head, and are colored gray with brown speckling and a smooth texture. Because of the size of the eggs, a Dimorphodon can lay only a small number of them; they appear to consistently lay three eggs every time. For the most part, the eggs appear able to withstand ambient environmental conditions, but since they are left uncovered the parents probably brood them when the external temperature or humidity becomes unfavorable.
Dimorphodons are protective of their nests and will defend the communal nesting grounds together. One by itself might be able to keep a small predator at bay, but when they act as one unit, they become a formidable array of teeth which can drive off most threats. When one Dimorphodon finds the nesting grounds in danger, it will emit a warning cry which alerts the rest of the flock immediately. As soon as this warning cry is heard, the whole flock will rally to drive away the predator. These flocks consist of both males and females, and multiple age groups coexist as well. This suggests that younger Dimorphodons assist the mature adults, similar to some birds.
While medium to small dinosaur eggs incubate for a period of several months (as do the eggs of larger pterosaurs like Pteranodon), the incubation period of Dimorphodon is unknown.
As a social animal, it should come as no surprise that the Dimorphodon is highly vocal. It makes a variety of chirping and gibbering sounds to communicate with others of its own kind, though the nature of these communications (i.e. to identify food sources, advertise to mates, or establish dominance) have not been studied. In particular, the chirping sounds are said to be made during the night. When frightened or aggressive, Dimorphodon makes clicking or chittering noises, and can sometimes be heard screeching when agitated. When faced with a threat, it will usually make such noises before taking flight, suggesting that this sound is meant to signal to the others to follow that individual along a possible route to safety.
One of Dimorphodon‘s cries is fully understood: it has a distinctive warning or alarm cry, which is heard as a very loud and high-pitched repetitive screeching. When other Dimorphodons hear this cry, they will immediately rally toward the one making the noise. This sound is different from the usual calls it makes when it is agitated in that it signifies a threat that the whole flock should respond to, such as a predator in the nesting grounds. Dimorphodon will become aggressive and chase off whatever danger the first animal indicates.
Non-vocal communications are also known from this species; when angered, it will rear onto its hind legs and spread its wings in an intimidation display. This serves a dual purpose: it can be used to intimidate predators or territorial rivals, and also signals to other Dimorphodon that there is a threat being addressed.
Prey of the Dimorphodon includes mainly small animals such as insects, fish, and reptiles. It would, therefore, be low on the food chain; it can mostly only eat prey that fits in its mouth, only attacking larger prey when it is in a frenzied state. Because its jaws are not designed for biting off pieces of meat, it is unlikely that it could feed properly from larger carcasses.
As with most de-extinct species, Dimorphodon would have been affected by hematophagous (blood-drinking) parasites in its native time period. Mosquitoes are a common example of hematophagous creatures. It is not known if any modern parasites affect Dimorphodon this way.
Because of its smaller size and weak bite, Dimorphodon tends to be less aggressive and more cautious around other animals. It is shy and easily spooked, though, which can provoke it to attack.
This species appears to associate willingly with Pteranodon longiceps masranii. The nature of this relationship is likely commensal, though it may possibly be parasitic. Competition between the two for food sources appears to be nonviolent, and the Pteranodon tolerate the Dimorphodon nearby; they have not been observed to attack or threaten their smaller neighbors in any way. The Dimorphodon, on the other hand, benefit from the presence of Pteranodon in several ways. Most of these are commensal, in that they benefit the Dimorphodon without harming the Pteranodon. This may include protection from some predators, as the aggressive Pteranodon will drive away most animals. For example, when the pterosaurs’ territory was perceived as threatened by the helicopter JW001, the Pteranodon confronted the threat while the Dimorphodon remained within the aviary walls. The Pteranodon are also much more powerful fliers; the Dimorphodon are weak fliers, but can be seen riding along in the wake of the Pteranodon even when safer or more comfortable routes are available. This suggests that they use the drafts created by Pteranodon to cover distance more quickly.
There is another element to the relationship that is possibly parasitic; during the December 22, 2015 incident, Pteranodon were attacked by both Indominus rex and Mosasaurus maximus. In both cases, Dimorphodon were also present, but the predators ignored them in favor of the larger pterosaurs. This pattern suggests that Dimorphodon may use the larger size of their neighbors to evade notice by large predatory animals. However, the two are not always seen together. After their release from the Jurassic World Aviary, the Pteranodons nested in Isla Nublar’s Eastern Ridge, while the Dimorphodons nested in the Western Ridge. Furthermore, Dimorphodons usually rest during the daytime while Pteranodons are active.
It is not known if any Dimorphodon still inhabited the area surrounding the Jurassic World Lagoon by 2018, as the Pteranodon had mostly migrated north. If any remained, they would have shared territory with Dilophosaurus, Compsognathus, Brachiosaurus, and Tyrannosaurus. It is unlikely that the larger dinosaurs would interact with the comparatively minute Dimorphodon, but Compsognathus would probably compete with it for food, and the nocturnal Dilophosaurus may have preyed upon it. At their one-time nesting grounds at Lookout Point, predators in the lowlands included Allosaurus and Ceratosaurus, while the herbivore Ankylosaurus occasionally was found there. One ankylosaur had a brief conflict with a parent Dimorphodon defending its nest in June 2016. The hybrid theropod Scorpius rex also hunted there between February and June, and while it was not seen attacking Dimorphodons, its presence necessitated a gasoline explosion to distract it from a distance. The explosion annihilated the Dimorphodon nesting grounds.
The distinctive appearance of this pterosaur, as well as its relatively early and well-publicized discovery, make it a mainstay in paleoart and a common inspiration for pterosaur depictions in popular culture. It has become decidedly less positively received since the 2015 incident in Jurassic World, where it was implicated in a dramatic attack on tourists. Since that point in time, Dimorphodon has instead come to symbolize the idea that de-extinct life forms are threatening and harmful; its awkward and ugly appearance have not helped in this respect.
One species of Dimorphodon was named in honor of Dr. Robert L. Weintraub.
Flying animals present a challenge to maintain in captivity, but the ungainly Dimorphodon offers a bit of a reprieve from the struggle of pterosaur-keeping. It is not an excellent flier, preferring to ride in the wake of larger pterosaurs and mostly staying on the ground. When it takes to the air, it makes short and rapid flights somewhat like certain birds such as woodpeckers. Aviary structures meant to contain Dimorphodon should still be fully-enclosed, since it is a capable climber and glider. Just because it is less capable of long-distance flight does not mean it cannot fly at all, and in fact it can cover quite some ground if given the chance.
Its habitat should include sources of fresh water for it to swim, bathe, and hunt; salt water is also acceptable but not ideal. Most of its diet includes terrestrial animals such as insects and small reptiles, but it will happily feed on fish. Changing up an animal’s protein source is always healthy, and this goes for de-extinct reptiles too. To ensure its habitat is satisfactory, there should be plenty of foliage and cliffs to create a dynamic environment that keeps it occupied. It is not extremely intelligent, but still needs stimulation. This pterosaur is somewhat aggressive but can be kept alongside Pteranodon without issue.
While most of the animal welfare at Jurassic World was within acceptable parameters, the pterosaur aviary was one glaring exception. The structure was 430,000 square feet, which sounds large on paper but was in fact too small for the population size it held. A source of fresh water was present inside, but it was also too small. Overcrowding appears to have been an issue with both species of pterosaurs; while they are known for being gregarious, park managers should make sure that pterosaur populations remain within a manageable size and do not grow so large that they become stressed. Heightened aggression may make the animals exciting to view, but this is both dangerous and unethical.
As one of the first pterosaurs known to science, discovered by legendary paleontologist Mary Anning, Dimorphodon holds a special place in scientific history and our understanding of pterosaur evolution. It presents valuable information about these reptiles’ ecology and behavior patterns due to the quality of the rare fossil remains. Notably, the more recent finds in Mexico demonstrate that (as suggested by fossilized footprints) pterosaurs walk with a plantigrade gait rather than a digitigrade one. Dimorphodon has also been invaluable in determining pterosaur taxonomy, with some paleontologists suggesting it is one of the more primitive pterosaur species.
Since the advent of de-extinction, the Dimorphodon genome has been sequenced by International Genetic Technologies, opening this species up to genetic research.
Dimorphodon has been subject to political controversy since the 2015 incident, in which it was recorded attacking guests at Jurassic World after being accidentally released from captivity. While the brunt of the attack was instigated by Pteranodons, the smaller Dimorphodons also became frenzied and bit multiple guests. Despite the bizarre and unlikely circumstances leading up to the attack, Dimorphodon has since been demonized in the media as an undesirable, menacing, and dangerous creature representative of the supposed threat de-extinct life poses to humanity.
However, the stereotype of Dimorphodon as a bloodthirsty monster is far from deserved. Following the incident, experts cited by the Dinosaur Protection Group stated that the Jurassic World Aviary’s conditions were insufficient for the pterosaurs’ needs; for example, the area was too small, lacking a significant body of water beyond the small rivers present in the enclosure. Furthermore, they were unable to find the stimulation provided by active hunting as they would in the wild; despite their presumed low intelligence, this led them to become stressed. The resultant attack, these experts suggest, was the result of subpar care provided by Jurassic World staff rather than the inherent nature of the pterosaurs.
This pterosaur’s continued existence was debated between 2017 and 2018, as volcanic activity on Isla Nublar caused the decline of the insular ecosystem. As a predatory animal, the proposal to rescue Dimorphodon was particularly controversial; despite lobbying from the DPG it was ultimately decided to do nothing to save the animals. This reptile’s unfortunate and undeserved reputation as a killing machine likely played a role in the government’s non-action decision.
In the Genetic Age, this animal has been brought back from extinction and is useful as a living specimen. Previously, it was known for its valuable fossil remains. All de-extinct animals are sources of novel biopharmaceutical compounds, due to their unique biological attributes and genetic modifications. Since Dimorphodon is a pterosaur, it would have even more unique qualities than the dinosaurs; it has no very close living relatives. However, specifics on what compounds have been sourced from it are unavailable at this time.
This pterosaur was being engineered for Jurassic Park as of 1993, but was not viable at the time development on the Park came to a halt. It was eventually cloned for Jurassic World years later. Advertisements for the aviary heavily focused on Pteranodon, with Dimorphodon being mostly ignored in marketing. It was, however, referenced in the Romance Package, with Masrani Global describing the chirping sounds of the animals as a part of the nighttime ambiance for couples sleeping in tents under the stars.
This is a somewhat aggressive pterosaur and is prone to biting. It should generally only be handled by people with experience, and as it is markedly different from most modern animals, there are few animal specialists really equipped to deal with it other than those trained specifically for small toothy pterosaurs. Giving this animal its distance is the best way to avoid an altercation; it is surprisingly fast on the ground and a good climber, so it is inadvisable to get close enough to provoke it at all. Dimorphodon, like most de-extinct animals, has never been hunted and so shows no fear of humans, so it will defend itself if it feels threatened. Unprovoked attacks have been reported, with food being the motivating factor. While a human is larger than a Dimorphodon‘s usual meal (it feeds almost entirely on animals smaller than itself), it may attack you looking for food you are carrying. If you are being chased, dropping whatever you have on you may distract it.
A Dimorphodon attacking something the size of a human is at a disadvantage and knows this, so it will try to gain the upper hand by disabling or disorienting its opponent. A common tactic is a feet-first tackle or flying headbutt to knock its enemy to the ground. If you can maintain your footing, you are more likely to be able to drive it off. If a physical fight is necessary, grab it by the neck with both hands to prevent it from twisting around and biting you, holding it at arm’s length to get it away from your face. It will probably try to bite at your throat, since this is where you are most vulnerable; it will use its wings to try and propel itself forward or bat at your head. Keep your wits about you and keep your arms stiff so that it cannot push itself closer. In the event that a Dimorphodon lunges at you and you cannot grab it in time, try to block it with your arm; wearing thick protective clothing will benefit you in this case. Its teeth are sharp, but its jaws are designed to snap and hold small prey rather than a larger enemy. If it does puncture your skin, do not try to push it away, since this will result in tearing wounds. Its jaws are not designed to rip pieces of flesh off of prey: if it can be forced to release its grip, you will suffer only puncture wounds rather than larger gashes.
While this animal is bold and has a frightening appearance, remember that it is not very strong. Most people are probably capable of wrestling it away with minor injuries in a normal situation, and your odds are greater if you can arm yourself with any blunt object to strike it. Unlike many animals it is not advisable to try and frighten it away with loud noises, as this will actually provoke it, but making yourself appear larger and capable of harming it may discourage it from persisting in its attack. The greatest danger is a combined flock attack: should you spot large groups of pterosaurs amassing, especially near bodies of water or large groups of prey animals, immediately seek a defensible shelter in case a feeding frenzy occurs. Buildings and vehicles are good sturdy shelters, but avoid structures with large windows. Like birds, pterosaurs struggle to see glass and will often crash into it when agitated, and shattered glass can be just as dangerous as the animals themselves. Another reason for swarming attacks is defense of the nesting grounds. They nest communally, and if one Dimorphodon sees a threat, it will quickly summon its flock. If you spot nests with eggs, immediately leave the area and try not to disturb the nests at all. This situation is even more dangerous than a feeding frenzy. A Dimorphodon will probably not try to eat you, but it will fight to defend its eggs against any threat no matter how intimidating.
Behind the Scenes
The Dimorphodon was one of the favorite creatures of director Colin Trevorrow and producer Patrick Crowley, being selected for 2015’s Jurassic World for this reason.