Biological issues in Jurassic Park
Encyclopedia
Jurassic Park, a book by Michael Crichton
, with a film version
directed by Steven Spielberg
, revolves around the resurrection of dinosaur
s via genetic engineering
. Scientists and enthusiasts have brought up a number of issues with facts and feasibility. Some of the speculative or inaccurate features attributed to the dinosaurs of Jurassic Park have become embedded in popular culture, most popular among them being the idea of Tyrannosaurus
only seeing motion; giant, featherless, intelligent Velociraptor
s, and dwarf, frilled, poison-spitting Dilophosaurus
. In general, the novel is more accurate than the film, with Spielberg adding some features to the dinosaurs (like the frill on the dilophosaurs).
as a reference when writing his novel, and that work interpreted Deinonychus antirrhopus as a species of Velociraptor; it is closely related to Velociraptor mongoliensis, but is larger. In the novel, Deinonychus is mentioned, but the character Alan Grant then says that scientists have reclassified it as a species of Velociraptor.
The film makers had the size of the film's Velociraptor increased for dramatic reasons, and changed the shape of the snout. However, at the same time the film was being shot, paleontologists came across a larger dromaeosaurid species named Utahraptor
and the larger raptors remained, even though Utahraptor was substantially larger (21 feet long) than the film's raptors. At the start of the film, a Velociraptor skeleton is uncovered in Montana
; no examples of the dinosaur have been uncovered in the United States
(although both Deinonychus and Utahraptor are American dinosaurs). The fossil
skeleton is similarly inaccurately large. In the novel the character Alan Grant identifies the Montana fossil specimen as "antirrhopus" as opposed to the park's "mongoliensis"(as identified by Henry Wu) - meaning that the fossil specimen Grant's team found is actually Deinonychus
.
The high intelligence of the film's Velociraptors is considered unlikely by scientists, given the relative size of their brains and comparisons with modern animals.
It is now known that Velociraptor had feathers. Neither the film nor the novel dinosaurs had feathers; however, both were created before the discovery of feathered dinosaurs closely related to Velociraptor (e.g. Microraptor
). In Jurassic Park III
, the raptors were remodelled and small feather-like quills were added to the male
s' heads, while still looking similar to the original design.
As with other bipedal dinosaurs in the films, the hands of Velociraptor are depicted with the palms able to rotate, but this would have been anatomically impossible for the real animals, as their forearm bones (ulna
and radius
) could not rotate in this way. Their palms should have been relatively fixed facing each other, like a person about to clap
.
stands about 1.2 meters (4 ft) tall, while its real-life counterparts measured on the order of 6 meters (20 ft) long and 1.4 meters (4.5 ft) tall at the hips. According to a "Making-of
" book, this was a deliberate deviation from accuracy for stylistic purposes, and to differentiate it from the velociraptors. Thus likely it could have been a juvenile, as none other is seen whether in this film or another, and by Dennis Nedry adding: "I thought you were one of your big brothers" when encountering it. It also has a frill like the Australian frill-necked lizard
, which is not considered accurate by paleontologists. The novel's version is full-sized and lacks the frill. Both depictions of the dinosaur eject a potent, blinding venom in both their bite and their spit, like a spitting cobra
, and use it to hunt; the novel acknowledges the fact that this is not suggested by fossil evidence.
would be unable to see someone if he stayed still; however, evidence has shown T. rex to have had high visual acuity
and binocular vision
. Some argue that it would still be able to smell them regardless. In the novel, it is mentioned that the reason the dinosaurs can not see someone standing still, may be due to the frog DNA in their genome, and it is shown that other dinosaurs, such as the island's Maiasaura
, have this problem as well. This is not mentioned in the film, and instead it is shown as if the inability to see without movement was an actual trait of Tyrannosaurus (Dr. Grant poses this as a paleontological fact even before knowing about Jurassic Park and its use of genetic engineering). In the sequel novel, The Lost World, it is suggested that the Tyrannosaurus can in fact see inanimate objects, and was actually not hungry, but merely "playing" or attempting to threaten in the first encounter. A character who specifically attempted this technique dies when the T. rex sees him there and kills him; the character Ian Malcolm mentions that he was listening to "the wrong scientists."
Tyrannosaurus is also shown as being able to keep (sprinting) pace with a jeep traveling at considerable speed; however, it is debated within the paleontological community whether a T. rex could even achieve this speed in real life, much less maintain it for as long a period of time as the film depicts. Anatomically, its short forelimbs would have been unable to cushion an impact if it were to fall; meaning that accidents at such speeds could have been fatal. Also, biomechanical studies by Dr. John Hutchinson of the Royal Veterinary College
have shown that in order to run at this speed in a crouched position, Tyrannosaurus would have needed over 43% of its muscle mass in each leg. That would mean 86% of its muscle mass would be in its legs, leaving little room for anything else in its body: a physical impossibility. Dr. Hutchinson’s work also suggests that an upper speed limit for Tyrannosaurus would, actually, only fall in the 10–25 mph range. Animators at Industrial Light & Magic were forced to use optical illusions in order to make the computer-generated Tyrannosaurus appear to convincingly keep pace with the vehicle.
in the film is shown to be chewing its food with a side to side motion of its lower jaw. In reality, it could not feed like this. Brachiosaurid skulls and jaws were limited to up and down motions, and their teeth were specialized for shearing and cropping plant material. Other sauropods, such as diplodocoids
, could move their jaws backward and forward, but were probably using this motion to strip branches, not to chew plants . Instead of processing food in the mouth, sauropods probably relied on taking in as much food as possible and processing it farther down the digestive tract, either through gastrolith
s (rocks swallowed and used for grinding in a gizzard
-like organ; note however that this hypothesis, while common in the popular literature, is now considered unlikely in sauropods), or simply by digestion through fermentation by microorganisms.
One of the most well known scenes of the movie shows a brachiosaur rearing into a bipedal stance. However, a biomechanical analysis of sauropod rearing abilities shows that Brachiosaurus is probably the sauropod least able to rear. It has a center of mass placed further forward than any other sauropod, which means that a bipedal or tripodal pose would be highly unstable. The legs and feet of the brachiosaurs were also portrayed as too bulky, whereas they would have been slender in reality.
in the novel, the Pteranodon
in Jurassic Park III
is interpreted as aggressive and able to pick a teenager up with its feet (a similar scene was planned for the climax of The Lost World: Jurassic Park
, but scrapped when Steven Spielberg
decided to instead use the Tyrannosaurus rampage in San Diego as a better finale). Both pterosaur
genera were thought to have eaten fish, and were incapable of grasping with their feet. However, in the novelization it states that they were able to carry things with their feet due to them being genetically engineered. Also, although the name Pteranodon means 'winged without teeth' or 'toothless wing', the Pteranodon in Jurassic Park 3 have small, sharp teeth in their bills. Their beaks are also straight, whereas they should have an upwards bend. There was great variation in individual Pteranodon crests, with large ones being interpreted as those of males, and short ones being female or juvenile. In the films, all adults have identical crests, and the crests of the juveniles are too large.
are given several attributes in the novels that cannot be determined from the fossil evidence to date. They are presented as living and hunting in large groups; as scavenger
s and coprophagists
(eaters of feces
), useful in keeping the park clean of sauropod excrement; and as secreting a venom described as similar to that of a cobra
, although more primitive. In the films, they are dropped in favour of Compsognathus
, as well as their venomous
bite.
Procompsognathus is known from a single partial skeleton from the Late Triassic
of Germany
, with a partial skull that may belong to it or, more likely, an early relative
of modern crocodilia
ns. Because only one individual is known, there is no direct evidence that it lived in groups; however, related animals such as Coelophysis
and Megapnosaurus
have been found in groups of numerous individuals, such as at Ghost Ranch
. As there are no uncontroversial remains of the head of Procomposognathus, its diet cannot be inferred from the form of its teeth and jaws; other coelophysoids
are seen as carnivores with skull adaptations that may have been advantageous when handling small prey.
There is no evidence that the bite of Procompsognathus was venomous. A venomous bite has been proposed for a possible theropod from the Late Cretaceous
of Baja California
, known from a single tooth with grooving similar to that found on the teeth of venomous snakes and lizards. A venomous bite has also been proposed for the Lower Cretaceous Chinese dromaeosaurid Sinornithosaurus
, based on its long grooved teeth similar to those of rear-fanged snakes, as well as a possible venom-gland cavity in the bone of the upper jaw.
Michael Crichton
John Michael Crichton , best known as Michael Crichton, was an American best-selling author, producer, director, and screenwriter, best known for his work in the science fiction, medical fiction, and thriller genres. His books have sold over 200 million copies worldwide, and many have been adapted...
, with a film version
Jurassic Park (film)
Jurassic Park is a 1993 American science fiction adventure film directed by Steven Spielberg. The film is based on the novel of the same name by Michael Crichton. It stars Sam Neill, Laura Dern, Jeff Goldblum, Richard Attenborough, Martin Ferrero, and Bob Peck...
directed by Steven Spielberg
Steven Spielberg
Steven Allan Spielberg KBE is an American film director, screenwriter, producer, video game designer, and studio entrepreneur. In a career of more than four decades, Spielberg's films have covered many themes and genres. Spielberg's early science-fiction and adventure films were seen as an...
, revolves around the resurrection of dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
s via genetic engineering
Genetic engineering
Genetic engineering, also called genetic modification, is the direct human manipulation of an organism's genome using modern DNA technology. It involves the introduction of foreign DNA or synthetic genes into the organism of interest...
. Scientists and enthusiasts have brought up a number of issues with facts and feasibility. Some of the speculative or inaccurate features attributed to the dinosaurs of Jurassic Park have become embedded in popular culture, most popular among them being the idea of Tyrannosaurus
Tyrannosaurus
Tyrannosaurus meaning "tyrant," and sauros meaning "lizard") is a genus of coelurosaurian theropod dinosaur. The species Tyrannosaurus rex , commonly abbreviated to T. rex, is a fixture in popular culture. It lived throughout what is now western North America, with a much wider range than other...
only seeing motion; giant, featherless, intelligent Velociraptor
Velociraptor
Velociraptor is a genus of dromaeosaurid theropod dinosaur that existed approximately 75 to 71 million years ago during the later part of the Cretaceous Period. Two species are currently recognized, although others have been assigned in the past. The type species is V. mongoliensis; fossils...
s, and dwarf, frilled, poison-spitting Dilophosaurus
Dilophosaurus
Dilophosaurus was a theropod dinosaur from the Sinemurian stage of the Early Jurassic Period, about 193 million years ago. The first specimens were described in 1954, but it was not until over a decade later that the genus received its current name...
. In general, the novel is more accurate than the film, with Spielberg adding some features to the dinosaurs (like the frill on the dilophosaurs).
Velociraptor
The Velociraptor in the novel, and consequently the film, were larger than the actual animal. The misconception arose because Crichton used "Predatory Dinosaurs of the World" by Gregory S. PaulGregory S. Paul
Gregory Scott Paul is a freelance researcher, author and illustrator who works in paleontology, and more recently has examined sociology and theology. He is best known for his work and research on theropod dinosaurs and his detailed illustrations, both live and skeletal...
as a reference when writing his novel, and that work interpreted Deinonychus antirrhopus as a species of Velociraptor; it is closely related to Velociraptor mongoliensis, but is larger. In the novel, Deinonychus is mentioned, but the character Alan Grant then says that scientists have reclassified it as a species of Velociraptor.
The film makers had the size of the film's Velociraptor increased for dramatic reasons, and changed the shape of the snout. However, at the same time the film was being shot, paleontologists came across a larger dromaeosaurid species named Utahraptor
Utahraptor
Utahraptor is a genus of theropod dinosaurs, including the largest known members of the family Dromaeosauridae. Fossil specimens date to the upper Barremian stage of the early Cretaceous period...
and the larger raptors remained, even though Utahraptor was substantially larger (21 feet long) than the film's raptors. At the start of the film, a Velociraptor skeleton is uncovered in Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
; no examples of the dinosaur have been uncovered in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
(although both Deinonychus and Utahraptor are American dinosaurs). The fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
skeleton is similarly inaccurately large. In the novel the character Alan Grant identifies the Montana fossil specimen as "antirrhopus" as opposed to the park's "mongoliensis"(as identified by Henry Wu) - meaning that the fossil specimen Grant's team found is actually Deinonychus
Deinonychus
Deinonychus was a genus of carnivorous dromaeosaurid dinosaur. There is one described species, Deinonychus antirrhopus. This 3.4 meter long dinosaur lived during the early Cretaceous Period, about 115–108 million years ago . Fossils have been recovered from the U.S...
.
It is now known that Velociraptor had feathers. Neither the film nor the novel dinosaurs had feathers; however, both were created before the discovery of feathered dinosaurs closely related to Velociraptor (e.g. Microraptor
Microraptor
Microraptor is a genus of small, four-winged dromaeosaurid dinosaurs. Numerous well-preserved fossil specimens have been recovered from Liaoning, China...
). In Jurassic Park III
Jurassic Park III
Jurassic Park III is a 2001 American science fiction film and the third of the Jurassic Park franchise. It is the only film in the series that is neither directed by Steven Spielberg nor based on a book by Michael Crichton, though numerous scenes in the movie were taken from Crichton's two books,...
, the raptors were remodelled and small feather-like quills were added to the male
Male
Male refers to the biological sex of an organism, or part of an organism, which produces small mobile gametes, called spermatozoa. Each spermatozoon can fuse with a larger female gamete or ovum, in the process of fertilization...
s' heads, while still looking similar to the original design.
As with other bipedal dinosaurs in the films, the hands of Velociraptor are depicted with the palms able to rotate, but this would have been anatomically impossible for the real animals, as their forearm bones (ulna
Ulna
The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form and runs parallel to the radius, which is shorter and smaller. In anatomical position The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form...
and radius
Radius
In classical geometry, a radius of a circle or sphere is any line segment from its center to its perimeter. By extension, the radius of a circle or sphere is the length of any such segment, which is half the diameter. If the object does not have an obvious center, the term may refer to its...
) could not rotate in this way. Their palms should have been relatively fixed facing each other, like a person about to clap
Clapping
A clap is the sound made by striking together two flat surfaces, as in the body parts of humans or animals. Humans clap with the palms of their hands, often in a constant drone to express appreciation or approval , but also in rhythm to match sounds in music and dance...
.
Dilophosaurus
The film's DilophosaurusDilophosaurus
Dilophosaurus was a theropod dinosaur from the Sinemurian stage of the Early Jurassic Period, about 193 million years ago. The first specimens were described in 1954, but it was not until over a decade later that the genus received its current name...
stands about 1.2 meters (4 ft) tall, while its real-life counterparts measured on the order of 6 meters (20 ft) long and 1.4 meters (4.5 ft) tall at the hips. According to a "Making-of
Making-of
In cinema, a making-of, also known as behind-the-scenes, is a documentary film that features the production of a film or television program...
" book, this was a deliberate deviation from accuracy for stylistic purposes, and to differentiate it from the velociraptors. Thus likely it could have been a juvenile, as none other is seen whether in this film or another, and by Dennis Nedry adding: "I thought you were one of your big brothers" when encountering it. It also has a frill like the Australian frill-necked lizard
Frill-necked Lizard
The frill-necked lizard , also known as the frilled lizard or frilled dragon, is found mainly in northern Australia and southern New Guinea. Its name comes from the large frill around its neck, which usually stays folded against the lizard's body. It is largely arboreal, spending the majority of...
, which is not considered accurate by paleontologists. The novel's version is full-sized and lacks the frill. Both depictions of the dinosaur eject a potent, blinding venom in both their bite and their spit, like a spitting cobra
Spitting cobra
A spitting cobra is one of several species of cobras that have the ability to eject venom from their fangs when defending themselves against predators. The sprayed venom is harmless to intact skin...
, and use it to hunt; the novel acknowledges the fact that this is not suggested by fossil evidence.
Tyrannosaurus
The film theorizes that the Tyrannosaurus rexTyrannosaurus
Tyrannosaurus meaning "tyrant," and sauros meaning "lizard") is a genus of coelurosaurian theropod dinosaur. The species Tyrannosaurus rex , commonly abbreviated to T. rex, is a fixture in popular culture. It lived throughout what is now western North America, with a much wider range than other...
would be unable to see someone if he stayed still; however, evidence has shown T. rex to have had high visual acuity
Visual acuity
Visual acuity is acuteness or clearness of vision, which is dependent on the sharpness of the retinal focus within the eye and the sensitivity of the interpretative faculty of the brain....
and binocular vision
Binocular vision
Binocular vision is vision in which both eyes are used together. The word binocular comes from two Latin roots, bini for double, and oculus for eye. Having two eyes confers at least four advantages over having one. First, it gives a creature a spare eye in case one is damaged. Second, it gives a...
. Some argue that it would still be able to smell them regardless. In the novel, it is mentioned that the reason the dinosaurs can not see someone standing still, may be due to the frog DNA in their genome, and it is shown that other dinosaurs, such as the island's Maiasaura
Maiasaura
Maiasaura is a large duck-billed dinosaur genus that lived in the area currently covered by the state of Montana in the Upper Cretaceous Period , about 74 million years ago....
, have this problem as well. This is not mentioned in the film, and instead it is shown as if the inability to see without movement was an actual trait of Tyrannosaurus (Dr. Grant poses this as a paleontological fact even before knowing about Jurassic Park and its use of genetic engineering). In the sequel novel, The Lost World, it is suggested that the Tyrannosaurus can in fact see inanimate objects, and was actually not hungry, but merely "playing" or attempting to threaten in the first encounter. A character who specifically attempted this technique dies when the T. rex sees him there and kills him; the character Ian Malcolm mentions that he was listening to "the wrong scientists."
Tyrannosaurus is also shown as being able to keep (sprinting) pace with a jeep traveling at considerable speed; however, it is debated within the paleontological community whether a T. rex could even achieve this speed in real life, much less maintain it for as long a period of time as the film depicts. Anatomically, its short forelimbs would have been unable to cushion an impact if it were to fall; meaning that accidents at such speeds could have been fatal. Also, biomechanical studies by Dr. John Hutchinson of the Royal Veterinary College
Royal Veterinary College
The Royal Veterinary College is a veterinary school located in London, United Kingdom and a constituent college of the federal University of London. The RVC was founded in 1791 and joined the University of London in 1949...
have shown that in order to run at this speed in a crouched position, Tyrannosaurus would have needed over 43% of its muscle mass in each leg. That would mean 86% of its muscle mass would be in its legs, leaving little room for anything else in its body: a physical impossibility. Dr. Hutchinson’s work also suggests that an upper speed limit for Tyrannosaurus would, actually, only fall in the 10–25 mph range. Animators at Industrial Light & Magic were forced to use optical illusions in order to make the computer-generated Tyrannosaurus appear to convincingly keep pace with the vehicle.
Brachiosaurus
The BrachiosaurusBrachiosaurus
Brachiosaurus is a genus of sauropod dinosaur from the Jurassic Morrison Formation of North America. It was first described by Elmer S. Riggs in 1903 from fossils found in the Grand River Canyon of western Colorado, in the United States. Riggs named the dinosaur Brachiosaurus altithorax,...
in the film is shown to be chewing its food with a side to side motion of its lower jaw. In reality, it could not feed like this. Brachiosaurid skulls and jaws were limited to up and down motions, and their teeth were specialized for shearing and cropping plant material. Other sauropods, such as diplodocoids
Diplodocoidea
Diplodocoidea was a superfamily of sauropod dinosaurs, which included some of the longest animals of all time, including slender giants like Supersaurus, Diplodocus, Apatosaurus, and Amphicoelias...
, could move their jaws backward and forward, but were probably using this motion to strip branches, not to chew plants . Instead of processing food in the mouth, sauropods probably relied on taking in as much food as possible and processing it farther down the digestive tract, either through gastrolith
Gastrolith
A gastrolith, also called a stomach stone or gizzard stones, is a rock held inside a gastrointestinal tract. Gastroliths are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth. The grain size depends upon the size of the animal and the gastrolith's...
s (rocks swallowed and used for grinding in a gizzard
Gizzard
The gizzard, also referred to as the ventriculus, gastric mill, and gigerium, is an organ found in the digestive tract of some animals, including birds, reptiles, earthworms and some fish. This specialized stomach constructed of thick, muscular walls is used for grinding up food; often rocks are...
-like organ; note however that this hypothesis, while common in the popular literature, is now considered unlikely in sauropods), or simply by digestion through fermentation by microorganisms.
One of the most well known scenes of the movie shows a brachiosaur rearing into a bipedal stance. However, a biomechanical analysis of sauropod rearing abilities shows that Brachiosaurus is probably the sauropod least able to rear. It has a center of mass placed further forward than any other sauropod, which means that a bipedal or tripodal pose would be highly unstable. The legs and feet of the brachiosaurs were also portrayed as too bulky, whereas they would have been slender in reality.
Pteranodon
Like the CearadactylusCearadactylus
Cearadactylus is an extinct genus of large, Early Cretaceous pterosaur from South America. The type species is Cearadactylus atrox, described and named in 1985 by Giuseppe Leonardi and Guido Borgomanero. The genus name refers to the Brazilian state Ceará and combines this with Greek daktylos,...
in the novel, the Pteranodon
Pteranodon
Pteranodon , from the Late Cretaceous geological period of North America in present day Kansas, Alabama, Nebraska, Wyoming, and South Dakota, was one of the largest pterosaur genera and had a maximum wingspan of over...
in Jurassic Park III
Jurassic Park III
Jurassic Park III is a 2001 American science fiction film and the third of the Jurassic Park franchise. It is the only film in the series that is neither directed by Steven Spielberg nor based on a book by Michael Crichton, though numerous scenes in the movie were taken from Crichton's two books,...
is interpreted as aggressive and able to pick a teenager up with its feet (a similar scene was planned for the climax of The Lost World: Jurassic Park
The Lost World: Jurassic Park
The Lost World: Jurassic Park is a 1997 science fiction thriller film, directed by Steven Spielberg. The film was produced by Bonnie Curtis, Kathleen Kennedy, Gerald R. Molen and Colin Wilson...
, but scrapped when Steven Spielberg
Steven Spielberg
Steven Allan Spielberg KBE is an American film director, screenwriter, producer, video game designer, and studio entrepreneur. In a career of more than four decades, Spielberg's films have covered many themes and genres. Spielberg's early science-fiction and adventure films were seen as an...
decided to instead use the Tyrannosaurus rampage in San Diego as a better finale). Both pterosaur
Pterosaur
Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...
genera were thought to have eaten fish, and were incapable of grasping with their feet. However, in the novelization it states that they were able to carry things with their feet due to them being genetically engineered. Also, although the name Pteranodon means 'winged without teeth' or 'toothless wing', the Pteranodon in Jurassic Park 3 have small, sharp teeth in their bills. Their beaks are also straight, whereas they should have an upwards bend. There was great variation in individual Pteranodon crests, with large ones being interpreted as those of males, and short ones being female or juvenile. In the films, all adults have identical crests, and the crests of the juveniles are too large.
Procompsognathus and Compsognathus
The ProcompsognathusProcompsognathus
Procompsognathus is a genus of small theropod dinosaur that lived during the late Triassic period , about 210 million years ago. Procompsognathus was named by Eberhard Fraas in 1913. He named the type species, P...
are given several attributes in the novels that cannot be determined from the fossil evidence to date. They are presented as living and hunting in large groups; as scavenger
Scavenger
Scavenging is both a carnivorous and herbivorous feeding behavior in which individual scavengers search out dead animal and dead plant biomass on which to feed. The eating of carrion from the same species is referred to as cannibalism. Scavengers play an important role in the ecosystem by...
s and coprophagists
Coprophagia
Coprophagia or coprophagy is the consumption of feces, from the Greek κόπρος copros and φαγεῖν phagein . Many animal species practice coprophagia as a matter of course; other species do not normally consume feces but may do so under unusual conditions...
(eaters of feces
Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
), useful in keeping the park clean of sauropod excrement; and as secreting a venom described as similar to that of a cobra
Cobra
Cobra is a venomous snake belonging to the family Elapidae. However, not all snakes commonly referred to as cobras are of the same genus, or even of the same family. The name is short for cobra capo or capa Snake, which is Portuguese for "snake with hood", or "hood-snake"...
, although more primitive. In the films, they are dropped in favour of Compsognathus
Compsognathus
Compsognathus was a small, bipedal, carnivorous theropod dinosaur. The animal was the size of a turkey and lived around 150 million years ago, the early Tithonian stage of the late Jurassic Period, in what is now Europe. Paleontologists have found two well-preserved fossils, one in Germany...
, as well as their venomous
Venom
Venom is the general term referring to any variety of toxins used by certain types of animals that inject it into their victims by the means of a bite or a sting...
bite.
Procompsognathus is known from a single partial skeleton from the Late Triassic
Late Triassic
The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...
of Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, with a partial skull that may belong to it or, more likely, an early relative
Crocodylomorpha
The Crocodylomorpha are an important group of archosaurs that include the crocodilians and their extinct relatives.During Mesozoic and early Tertiary times the Crocodylomorpha were far more diverse than they are now. Triassic forms were small, lightly built, active terrestrial animals. These were...
of modern crocodilia
Crocodilia
Crocodilia is an order of large reptiles that appeared about 84 million years ago in the late Cretaceous Period . They are the closest living relatives of birds, as the two groups are the only known survivors of the Archosauria...
ns. Because only one individual is known, there is no direct evidence that it lived in groups; however, related animals such as Coelophysis
Coelophysis
Coelophysis , meaning "hollow form" in reference to its hollow bones , is one of the earliest known genera of dinosaur...
and Megapnosaurus
Megapnosaurus
Megapnosaurus was a dinosaur of the theropod family Coelophysidae, formerly called Syntarsus , living during the Early Jurassic. It was renamed by American entomologist Dr. Michael Ivie , Polish Australian Dr...
have been found in groups of numerous individuals, such as at Ghost Ranch
Ghost Ranch
Ghost Ranch is a retreat and education center located close to the village of Abiquiu in Rio Arriba County in north central New Mexico. The conference center and lodgings at Ghost Ranch are run by the Presbyterian Church but open to the general public.-History:Ghost Ranch is part of Piedra...
. As there are no uncontroversial remains of the head of Procomposognathus, its diet cannot be inferred from the form of its teeth and jaws; other coelophysoids
Coelophysoidea
Coelophysoids were common dinosaurs of the Late Triassic and Early Jurassic periods. They were widespread geographically, probably living on all continents. Coelophysoids were all slender, carnivorous forms with a superficial similarity to the coelurosaurs, with which they were formerly...
are seen as carnivores with skull adaptations that may have been advantageous when handling small prey.
There is no evidence that the bite of Procompsognathus was venomous. A venomous bite has been proposed for a possible theropod from the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
of Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
, known from a single tooth with grooving similar to that found on the teeth of venomous snakes and lizards. A venomous bite has also been proposed for the Lower Cretaceous Chinese dromaeosaurid Sinornithosaurus
Sinornithosaurus
Sinornithosaurus is a genus of feathered dromaeosaurid dinosaur from the early Cretaceous Period of the Yixian Formation in what is now China. It was the fifth non–avian feathered dinosaur genus discovered by 1999...
, based on its long grooved teeth similar to those of rear-fanged snakes, as well as a possible venom-gland cavity in the bone of the upper jaw.