Deinosuchus rugosus (S/F)

Deinosuchus rugosus was a very large species of alligatoroid native to North America during the Campanian epoch of the late Cretaceous period, from 82 to 73 million years ago. Its teeth were first discovered in 1858 by geologist Ebenezer Emmons (who assumed it to be a pliosaur), and its genus was named by W.J. Holland in 1909 following the 1904 discovery of osteoderms belonging to it. More remains were discovered in the 1940s, bolstering knowledge of the animal. While not a direct ancestor of the modern alligator, Deinosuchus had a number of morphological traits in common with them, and greatly resembled a larger version of the alligator. At the time it existed, North America was divided into two subcontinents by a warm sea known as the Western Interior Seaway. In the east was the subcontinent of Appalachia, while in the west was the subcontinent of Laramidia. Fossils of Deinosuchus have been found on ancient coastlines of both, and it is presumed to have been an apex predator. The scientific name means “rough, terrible crocodile,” in reference to its osteoderms and imposing size. The name is somewhat misleading, as it is more closely related to alligators than to crocodiles.

Some scientists consider Deinosuchus rugosus to be a dubious species, claiming that the remains from its habitat have not been properly described. This species is one of at least two and at most three known species of Deinosuchus; it grew to roughly 26 feet long, inhabiting the Appalachian subcontinent. Laramidia was home to the larger Deinosuchus hatcheri, and the similarly large Deinosuchus riograndensis lived farther south. These latter two may represent a single species, and reached a maximum size of 32 to 39 feet in length. However, despite its huge size, Deinosuchus was not the largest crocodilian ever to live. The North African Sarcosuchus, Indian Rhamphosuchus, and South American Purussaurus all grew to equal or larger size.

InGen utilized Deinosuchus rugosus genetic material in engineering the artificial species Indominus rex, which hatched in 2012. There is scant evidence that InGen recreated D. rugosus itself.


Deinosuchus mostly resembles the modern-day American alligator (Alligator mississippiensis), but is significantly larger in size. The species D. rugosus in particular reaches lengths of 26 feet. This makes it larger than any living crocodilian, including the saltwater crocodile (Crocodylus porusus), though not larger than several genera of crocodilian which existed later in time than Deinosuchus. Like its modern relatives, it was a bulky quadruped with lengthy jaws ending in a round, U-shaped snout with nostrils on the top. Its teeth were thick and robust, with the teeth toward the snout being sharper and designed for puncturing flesh while the teeth in the rear of the mouth were blunter and rounded for crushing armor and shells. Each premaxilla had four teeth, each maxilla had twenty-one or twenty-two teeth, and the dentaries of the lower jaw had at least twenty-two teeth each. When the jaw was closed, only the fourth tooth of the lower jaw would protrude. This animal is estimated to have had a bite force of 18,000 to 102,803 Newtons. If the higher estimates are correct, then its bite force would exceed even that of Tyrannosaurus rex.

Holographic display of Indominus rex, indicating that Deinosuchus rugosus was used to design its dentition.

Also like modern crocodilians, the body of Deinosuchus is covered in bony osteoderms, which function both as armor and as attachment points for connective tissue. Deep pits and grooves in the osteoderms worked to connect with this tissue. In combination, these osteoderms and connective tissue would work as a load-bearing system to support the bulk of the animal when it was out of the water. The osteoderms were larger than average, and many were shaped like hemispheres.

Deinosuchus is believed to have had a lengthy tail constituting almost half its total length. This tail would have probably been highly muscular for propulsion when swimming. The limbs would likely have been small, but also muscular, with little use in swimming but necessary for dragging its heavy body over land.

Its coloration is currently unknown, but it is probably camouflaged for its ambush-hunting lifestyle. Modern crocodilians have green, brown, gray, and yellow colors to help blend in with mud and vegetation.


Hatchling and juvenile stages have not been observed. Most modern crocodilians somewhat resemble adults when they hatch, though with disproportionately larger heads and eyes, and sometimes brighter coloration. The mobile game Jurassic Park: Builder depicts young Deinosuchus as smaller versions of the adults.

Fossil evidence suggests that Deinosuchus reached adulthood in about 35 years, and may have had a lifespan of more than 50 years.

Sexual Dimorphism

So far, no sexual dimorphism in Deinosuchus has been documented.

Preferred Habitat

Deinosuchus is presumed to have inhabited estuarine environments and brackish-water bays. As with all similar crocodilians, it would have been semiaquatic, being an excellent swimmer but still capable of walking on land. In particular, D. rugosus inhabited Appalachia, a subcontinent of North America that existed during the Campanian. Fossils are known from the tropical coasts of the Western Interior Seaway, as well as the Atlantic coast of the subcontinent. It is unknown if Deinosuchus could tolerate saltwater or if it ever ventured out to sea.

The mobile game Jurassic Park: Builder incorrectly portrays Deinosuchus as living comfortably on the frozen Patagonian coast, near El Chaltén within Los Glaciares National Park. In reality, an ectothermic crocodilian could not survive in this kind of environment.

Isla Nublar
Deleted footage featuring what may be a Deinosuchus skeleton. The size indicates that it would be a subadult, if it is indeed a Deinosuchus and not some other variety of alligatoroid.

While Deinosuchus DNA was utilized to design the tooth morphology of Indominus rex, it is not known if any were actually created by InGen. The only evidence of its existence is a single skeleton seen to the southwest of Mount Sibo on June 23, 2018; the skeleton appears to belong to a large alligatoroid similar to Deinosuchus, but its identity is unconfirmed. Deinosuchus is absent from a list of de-extinct life on Isla Nublar created by the Dinosaur Protection Group; if it was indeed cloned, then either Jurassic World administration was unaware of it (similarly to Troodon), or the DPG’s members simply neglected to include it in the list. It is not the only species missing from the list for unknown reasons, as both Teratophoneus and Peloroplites are similarly absent despite confirmation of their existence on Isla Nublar.

The skeleton was found in a heavily-forested region in a small creek. If any survived until 2018, it is likely that the June 23 eruption of Mount Sibo would have wiped out their food sources and, consequently, any surviving Deinosuchus.

Isla Sorna

There is no evidence that Deinosuchus was ever present on Isla Sorna.


As it is not known whether Deinosuchus was actually created at any point (or, if so, if any survived), there is no evidence for it being brought to the mainland in any form.

Behavior and Ecology
Daily Activity

As an ectothermic (cold-blooded) reptile, Deinosuchus would most likely be diurnal or cathermal, resting during the night.

Diet and Feeding Behavior

The estuarine habitat of Deinosuchus would enable it to hunt both terrestrial animals, such as dinosaurs and pterosaurs, as well as aquatic animals such as fish. Its teeth were adapted for multiple uses, with the front ones designed to puncture flesh while the rear ones were designed to crush shells and bony armor. It could have theoretically fed on shellfish and armored animals such as turtles. There is some debatable fossil evidence of Deinosuchus hunting hadrosaurs, and certainly its large size would enable it to prey on some of the dinosaurs it lived alongside.

Many modern crocodilians will ambush prey at the water’s edge, then submerging the prey until it drowns. Fossil evidence and biomechanical studies suggest that Deinosuchus could perform a death-roll like some modern crocodilians, killing captured prey by internal injury.

As no living specimens have been documented so far, it is not known what the prey of de-extinct Deinosuchus would include. However, some larger animals known from its possible locality on Isla Nublar include Stegosaurus, Sinoceratops, and Peloroplities.

Social Behavior

No evidence currently exists to provide any information on the social behavior of Deinosuchus, though many modern crocodilians are comfortable living in large groups.


Nearly all crocodilians lay eggs to reproduce, the only possible exceptions being certain fully-marine lineages. As of such, the Deinosuchus almost certainly laid eggs. Crocodilians utilize cloacae as reproductive organs, though the male possesses a median penis. The sex of the offspring is determined by temperature; moderate temperatures result in males, while temperature extremes result in females. Most modern crocodilians, including close relatives of Deinosuchus, engage in complex courtship rituals, extensive nest-building, and extended parental care given by the mother; it is possible that Deinosuchus also exhibited these behaviors.

The extant American alligator, which is closely related to Deinosuchus, lays 35 to 90 eggs and incubates them in a nest for about sixty-five days. As Deinosuchus is much larger in size, its clutch size and incubation period may have differed from the American alligator.


The exact vocalizations of Deinosuchus are not known. Modern alligators are able to produce hissing sounds when threatened, and some (particularly males) will forcefully exhale to make a loud throaty bellowing noise. This may be used as a display call, advertising to mates and threatening rivals. Crocodilians lack vocal organs, so their vocalizations are limited. They mostly communicate through body language.

Ecological Interactions

Deinosuchus rugosus was smaller than its relative Deinosuchus hatcheri, so while its larger relative was probably an apex predator, D. rugosus was more likely an opportunist. If it existed on Isla Nublar, it would have had competition with many genera of large carnivorous dinosaur, including Tyrannosaurus and the semiaquatic Baryonyx and Suchomimus. A single skeleton possibly belonging to D. rugosus was featured in deleted footage, implying that (if the skeleton was indeed from this species) it was at least found near Mount Sibo’s heavily-forested southwestern slopes. A creek was present at that location, though it was not deep enough for the animal to submerge.

Within the region of island where the skeleton was found, known species of dinosaur included the armored herbivores Peloroplities and Stegosaurus, ceratopsian Sinoceratops, the diminutive carnivore Compsognathus, large pterosaur Pteranodon, and a single Velociraptor.

At least in prehistory, Deinosuchus was affected by hematophagous (blood-drinking) parasites, possibly mosquitoes.

It is possible that the species had already died out by June 23, 2018 when the skeleton was found, likely due to competition from the excessive number of predators on Isla Nublar after the island was abandoned by Masrani Global Corporation.

Cultural Significance

While Deinosuchus does not share the same symbolic meanings in art and culture as modern alligators, it is fairly well-known even to laypeople (though they may not know its scientific name). The imagery of a gigantic crocodilian capable of going toe-to-toe with large predatory dinosaurs and even overpowering them is exciting and compelling to many people, so this reptile is frequently depicted.

In Captivity

There is currently no concrete proof that Deinosuchus was actually brought back from extinction, so nothing can be said for certain about its needs in captivity. However, its requirements can be extrapolated both from paleontological evidence and its extant relatives, such as the American alligator.

Despite being a large carnivorous animal the alligator has been successfully kept in captivity and even farmed. The alligator needs a semi-aquatic habitat, with fresh water deep enough to submerge in and land on which to bask in the sun. It can tolerate cold but really flourishes in warmer climates. Alligators will accept most forms of meat, and so are commonly fed commercially-available foods such as poultry and fish. They are capable of climbing, and so their enclosures are normally walled with sheer surfaces to ensure that they remain inside; this also ensures that people viewing them are kept at a safe distance. Alligators can be kept in sizable groups, but naturally a larger population will mean a larger enclosure is needed, and the food supply will necessarily also be scaled up.

Again, there is currently no evidence that Deinosuchus has actually been recreated. If it were, it is likely that its captivity requirements would be somewhat similar to those of the alligator, but with accommodations made for its larger body size and the warmer temperatures of its original time period.


Along with the irreplaceable knowledge gained about ancient American ecosystems from studying the fossils of this enormous reptile, Deinosuchus has contributed significantly to science in the Genetic Age. Its genome has been sequenced by International Genetic Technologies and many of the functional genes have been identified. For example, the genes which regulate the growth of teeth are well-understood thanks to research taking place in the twenty-first century. This not only provides new insight into the ancient animal’s biology, it also enables herpetologists to better understand the evolutionary history of alligatoroids including those alive today.


This crocodilian was not mentioned by the Dinosaur Protection Group during the Mount Sibo controversy, and it is questionable whether or not InGen actually bred this animal at all, so it has not been a notable part of the de-extinct animal rights debate.

However, since it was used a component in the genomes of controversial hybrid genera, it does play a role in the bioethical quandaries regarding these animals’ existence. Because the genera that it has been sourced for were engineered explicitly for use as military animals, Deinosuchus DNA has essentially been made into a component of novel biological weapons in the modern age. Bioweapons regulations are often out of date, with restraints being challenged by developments in science and technology; should any of these products be used, it would likely lead to massive challenges to existing law and perhaps the creation of new legislature.


Deinosuchus rugosus was sourced as a component for the genome of Indominus rex by Dr. Henry Wu, particularly for the hybrid animal’s tooth morphology. It is otherwise a valuable addition to InGen’s genetic library. As with all prehistoric organisms, its long-extinct nature makes it a source of biopharmaceuticals not available from its modern equivalents, and this would make it useful to medicine; however, the exact substances that can be obtained from it are not yet known.

Modern crocodilians are valued for their scaly hides, which are used to make expensive leather products, as well as for their edible meat. It would not be impossible to harvest these resources from a living Deinosuchus, but killing de-extinct animals for resources is generally frowned upon due to their rarity and the expense involved in creating one. It would be more acceptable (and more profitable) to use it as a biological attraction, as Jurassic World may have intended to do eventually.

Crocodilians in the modern day are an essential part of wetland ecosystems and provide invaluable ecological services as apex predators. The massive size of Deinosuchus would make it efficient in this respect, but since it is not a natural part of the modern ecosystem, it would not be able to effectively replace its present-day relatives without upsetting the balance of a modern wetland significantly.


Crocodilians are among the natural predators of humans, so it is possible that a large species of crocodilian such as this one may view humans as prey. The American alligator is generally one of the more docile crocodilians, but it is far from safe to interact with, especially in the wild. A far larger species like D. rugosus might behave very differently than its modern relatives; until one is actually seen alive, nothing can be said for certain.

However, until such time comes that this species is de-extinct for sure, we can at the very least abide by the same safety procedures used for modern alligators. Swimming should be practiced with caution, and only in designated areas where wildlife officials have deemed it is safe. Under no circumstances should the animals be fed or harassed. The Texas Parks and Wildlife Department recommends keeping a distance of at least 30 feet from an alligator, and since D. rugosus grows to a much larger size, we at Jurassic-Pedia would recommend maintaining at least 50 feet of distance. Should any of the even larger Deinosuchus species be brought back from extinction, an even greater distance would be necessary.

Remember that, though they look sluggish on land, crocodilians can actually run quite fast and are very agile. It is likely that they could even outrun you, especially in areas with lots of undergrowth and slick mud. If you find yourself too close, back away slowly rather than running. A crocodilian is cold-blooded and therefore fast in short spurts, so you can use this to your advantage: if you can get a thirty-foot head start on an American alligator, it will eventually slow down. This is why the thirty-foot distance is recommended by experts. Bear in mind that Deinosuchus is larger, so it may be able to outpace you for longer than an American alligator; hence why we recommend keeping a greater distance.

Modern alligators hunt at dusk and dawn, so avoid the water at these times. At other times of day, they will bask in the sun; they are not hunting, but still are dangerous. If an alligator hisses, this is a sign of aggression. Deinosuchus probably warns intruders the same way. Avoid nests and small juvenile animals, and do not let pets or small children swim in or drink from water sources these animals use.

If attacked by an alligator, it may be possible to hold its jaws shut, since the muscles used to open the mouth are not as strong as those used to slam it shut. However, Deinosuchus is too large for you to do this. If you are being attacked, try to gouge its eyes, ears, or nostrils; this may cause it to release you, enabling you to escape. Your attacker may attempt a death roll, in which case you must hold your breath and roll in the water in the same direction as the animal; after this it will need a moment to recover its energy, which you can use to your advantage. Even if part of your body is in its mouth, all hope is not necessarily lost. It is possible to escape a crocodilian bite by drowning it. Strike the palatal valve, a flap of skin on the back of the throat, to let water in. By striking it repeatedly you can cause the attacker to begin drowning, at which point it will release you. Of course, avoiding the jaws in general is the best strategy.

Getting out of the water will drastically increase your odds of survival. Once you have escaped, ensure to get any wounds treated quickly. Since these animals live in sources of water, your injuries will probably become contaminated with waterborne bacteria, which can lead to infection.

Behind the Scenes

A piece of concept art for Jurassic World depicts an attraction where visitors would view large reptiles that appear to be crocodilian in nature. The visitors would walk on glass panels above the reptiles to view them. It is not known if these were intended to be Deinosuchus, or if any such attraction was ever considered for the theme park in-universe.