JURASSIC PARK

Is It Possible?
An analysis of what you saw, what is and what could be.



THE DINOSAURS OF THE JURASSIC PARK

Spinosaurus Tyrannosaurus-Rex Dilophosaurus
Brachiosaurus Velociraptor

THE PTEROSAURS OF JURASSIC PARK III

DID DINOSAURS HAVE FEATHERS?

TRAVELING IN HERDS

NESTS WITH DINOSAUR EGGS

THE ENVIRONMENTAL SETTING OF JURASSIC PARK

COLD-BLOODED OR WARM-BLOODED?

One of the most controversial issues since the 1960's
and one that continues to be debated among experts.

ARE DINOSAURS ALIVE TODAY AS BIRDS?

DINO DNA: BRINGING BACK DINOSAURS

WRITER'S PERSONAL NOTE

REFERENCES AND CREDITS

USING THESE CONCEPTS IN THE CLASSROOM



THE DINOSAURS OF THE JURASSIC PARK MOVIES


Across the span of the 3 Jurassic Park movies, we see the evolution of Tyrannosaurus rex from the ferocious predator seen in the first Jurassic Park movie into the scavenger who falls prey to the mighty Spinosaurus in Jurassic Park III.

And,what about the huge, fierce Spinosaurus? Could it kill a T.rex? Would it seek humans as its prey had both species coexisted simultaneously?

Is it even possible for science and technology to recreate animals long extinct?

Spinosaurus: whose name means "spiny lizard", was a huge meat-eating theropod, with a fan-shaped series of spines on its back, that lived during the middle Cretaceous period, about 95 million years ago.
It was 40-50 feet in length and weighed at least 4 tons, if not more. Some scientists claim 8 tons is not unreasonable. It is definitely the largest known spinosaurid.
The spinosaurus was bipedal (walked on 2 legs). It had a very large, long jaw with long teeth that were NOT serrated.
Like a T.rex, its forearms were shorter than its legs but were longer than other known theropods.
A mainstay of its diet may have been large fish which it could easily grasp in its long, wide, crocodile-like jaws. However, as pictured in the movie Jurassic Park III, the Spinosarus could definitely defeat a T-Rex with no problem just by virtue of the fact that it could swing its head around, open its wide mouth and grab the T.rex by the neck. That would give the Spinosaurus the advantage in the battle.
As for its ability to hunt humans as its prey had we lived at the same time period? Humans would most definitely have been prey for a Spinosaurus.

As to the function of Spinosaurus's huge sail-like fin? The spines reached up to 6 feet in height! Scientists speculate 2 possible functions for this sail.
One of its purpose could have been to regulate body temperature by collecting the sun's insolation and distributing it throughout its body. If this is true, then it could be an indication that Spinosaurus was cold-blooded contrary to many theories, based on new evidences, that dinosaurs were probably warm-blooded.
The other purpose of the sail could have been to attract a mate, especially if it were brightly colored as is the case with reptiles living today.

One problem though, Spinosaurus and Tyrannosaurus-Rex did not coexist on the same continent. They were an ocean apart. Spinosaurus was in present-day Africa while Tyrannosaurus-Rex roamed areas of present-day United States, Canada and east Asia. So, the battle is purely hypothetical, created for the movie alone. However, if the 2 could have existed at the same time in the same place...then yes, Spinosaurus could have been the victor.

Read More:
Spinosaurus Fact Sheet

Tyrannosaurus-Rex: Now, what about Tyrannosaurus rex's transformation from predator to scavenger in Jurassic Park III? This is still a heated debate among paleontologists.
T.rex has always been classified as a large meat-eating dinosaur with pointed, serrated teeth (for ripping through meat) that are continuously replaced.
Bipedal, its forearms were only 3 feet long with 2 fingered hands. It was about 15-20 feet high and weighed 5-7 tons. Lengthwise, T.rex averaged about 40 feet from head to tail.

Leading paleontologist, Jack Horner, sums up T.rex's hunting ability as follows: "Tyrannosaurus, says Jack Horner, was a nasty-looking, hunched-over beast that was a lousy runner with mediocre vision and had spindly little arms that would have been useless in a fight. Even worse, if T. rex tripped and fell or was toppled by a stubborn foe, those arms could do little to dampen the impact of tons of falling dinosaur; the all-but-inevitable broken bones could easily prove fatal.
But T. rex would have been a masterful scavenger. Huge olfactory gear could have smelled a carcass from miles away, and legs designed for walking — not running — could cover vast distances in search of carrion, much as olfactory-gifted vultures soar over the landscape for hours. And those vicious teeth were adept not at slicing through choice cuts of meat but at crushing the bones and cartilage left behind by the true hunters". 1

- The debate as to whether T.rex was a hunter or scavenger partly arises from the dinosaurs' short forelimbs.
Scientist Jack Horner asserts that T.rex never could have been a hunter because the forelimbs and 2 fingered hands were useless and ineffective for grabbing and holding onto struggling prey.
- Scientists counter Jack Horner's statements by pointing out that even today successful predators rarely use their forearms for the hunt and kill and maintain that it was the "jaws" and the deadly bite of the T.rex that made it an active and successful hunter and the purpose of the forearms was for balance.

- Mr. Horner also claims that T.rex's proportions would not allow it to be a good runner; therefore, it would not actively chase prey.
- Countering this belief, some scientists say that a T.rex could clock speeds of 12 mph even without running and this would be fast enough to pursue and catch a Hadrosaur or Triceratops.

- Horner further states that C.A.T. Scans of T.rex's cranium show a large olfactory lobe and small optical system. The implications here would be that T.rex was more like today's vulture, keen on "smelling" and poor on "seeing".
- However, T.rex's brain was not unlike today's alligator and they hunt very well, eating just about anything they perceive as food.2

The very idea that T.rex's behavior be changed from predator to scavenger continues to be a controversial one. Nevertheless, Jurassic Park III clearly embraced Jack Horner's suggestions that T.rex was "100% scavenger" and so the dinosaur was shown eating an already dead carcass.
Jack Horner was integral to the Jurassic Park movies. In the third movie Ellie mentions getting a quote from Jack Horner for her book. As it turns out, Jack Horner is the paleontologist who was Michael Chrichton's inspiration for the character of Alan Grant and Horner was also a consultant on all 3 Jurassic Park films.3 And so, his theories prompted the change in T.rex's eating behaviors in the third movie.

More recently, fossil discoveries have revealed this possibility: " 'When Dinosaurs Roamed America' also incorporates findings from New Mexico’s Zuni Basin that were published only a few weeks before the show’s television premiere. The most notable find was Nothronychus, a seeming relative of Tyrannosaurus rex that was a plant-eater instead of a meat-eater".4
Somehow I have my doubts that T.rex as a plant-eater will ever be accepted by the paleontological community.

Remain Still and he won't know you are there: In the first Jurassic Park film, as T.rex charges the car in which the 2 children were riding, Dr. Grant (who is in a different car) is heard yelling: "Don't move! A Tyrannosaurus ability to sense prey is based on "movement". Most paleontologists disagree with this assessment of T.rex's ability, comparing it to a "amphibian visual cortex", and feel that, even if the children did not move, the dinosaur would still be able to see their presence. In addition, static prey would no doubt be perceived by the T.rex's sense of smell.

Read More:
Tyrannosaurus rex Fact Sheet
T.rex's Diet
Tyrannosaurus: Hunter or Scavenger?


Dilophosaurus: In Jurassic Park I, Nedry drives his car on a rain soaked road, gets stuck in the mud and then gets out to try to free his vehicle. He meets a dinosaur that is quite small but which turns out to be a deadly adversary. The dinosaur threatens Nedry with a "neck frill" and then spits poisonous venom at him. "The cervical vertebrae on Dilophosaurus are very long, and they are one under the other, making a very strong support down the side of the neck". "And there is also a short anterior projection of these vertebrae (or ribs) which would make it impossible for the animal to erect a crest".5
In reality, at the time of the filming of Jurassic Park, Dilophosaurus, an early Jurassic period, meat-eating theropod, was known to be much larger than the dinosaur in the movie (18-20 ft) and the neck frill was speculative and not certain, as was its ability to spit venom.

Brachiosaurus:
The gigantic, plant-eating brachiosaurs, whose name means "Arm Lizard", first appeared in Jurassic Park I as Dr. Grant saw one of them stand on its hind legs and reach its long neck up to eat foliage from a tree.
In Jurassic Park III Dr. Grant and the children even pet one.
This long-necked creature was one of the largest and tallest dinosaurs that ever lived. Its front legs were longer than its hind legs and it was 40-50 feet (12-16 m) tall. Brachiosaurus was about 85 feet (26 m) long, and weighed about 33-88 tons and it lived in the middle to late Jurassic period, about 156-145 mya. Brachiosaurus was a sauropod, whose intelligence (EQ: as measured by its relative brain to body weight) was at the lowest end of the scale meaning it was not very smart at all. However, its sense of smell was probably very good since it had large nasal openings on the top of its head.

As for a Sauropod raising its head to munch on trees, as depicted not only in the Jurassic Park movies but also in all visual renderings of these dinosaurs, recent studies show this probably did not happen. Sauropods were probably grazing animals and ate low growing vegetation and shrubs.

"Michael Parrish at the University of Northern Illinois and Kent Stevens of the University of Oregon have painstakingly reconstructed the vertebrae structures of both the Apatosaurus and the smaller Diplodocus using a sophisticated computer simulation program called DinoMorph, written by Stevens. After specifically looking at the neck bones of both Sauropods – massive animals with long tails, long necks and small heads – it soon became clear that the animals could scarcely raise their heads much above five metres, significantly less than ever thought. "The maximum amount they were able to raise their heads was just a little bit above the height of their back," Parrish told the Associated Press. "If you raise the neck any higher, the vertebrae run into each other and the back locks up."6 And so it appears that Sauropods long necks favor lower, grazing positions and have a distinct "vertical limit".

Velociraptor: A fast running, bipedal dinosaur, Velociraptor, whose name means "Speedy Thief", was about 5 to 6 ft long, 3 ft tall and may have weighed about 15 to 33 pounds. It lived in Cretaceous period, about 85 - 80 mya.
A Velociraptor's stiff tail could only move up and down close to the body, where it can bend nearly 90 degrees straight up and was useful for balance.
Perhaps the most unique feature among all raptors (DROMAEOSAURIDS) is the sharp, sickle shaped claw (a second toe), that is hyper-extendable and which was used to grasp and to rip the flesh of its prey.

Velociraptor's intelligence (as measured by its relative brain to body weight) was the highest among the dinosaurs. However, this does not mean that a Velociraptor would be capable of opening a door! It's EQ (encephalization quotient, which is brain weight) was less than 0.20 which means its intelligence is equivalent to a modern day ostrich. Certainly, it was not as smart as a chimpanzee, nor could it do the amazing things shown to us in the movie, nevertheless it was probably the smartest dinosaur. (That certainly makes a person wonder what level of intelligence a a Brachiosaurus had)!

It is believed that Velociraptors did, in fact, hunt in packs, as portrayed in the Jurassic Park movies.

A dromaeosaurid (Sinornithosaurus) fossil that was recently unearthed in China appeared to have feathers covering its body. It is very possible that Velociraptor did, also and so Velociraptor has feathers in the third Jurassic Park movie.

The producers of Jurassic Park I acknowledged the fact that, in the movie, Velociraptor was larger than any fossils finds of that dinosaur species at that point in time. Perhaps, the true size was not ominous enough to impress movie viewers. The Velociraptor in the film was more like a Deinonychus (10 ft long, 5 ft tall, weight up to 175 pounds, Cretaceous period, about 110 to 100 mya).
Ironically, just before the movie was finished, a new species of raptor was discovered: a dromaeosaurid species named Utahraptor (16-23 ft long, weight possibly about 1 ton, mid-Cretaceous period, about 125 mya). It is the largest of all known raptor species. As luck would have it, Jurassic Park I was now more in keeping with the facts than it would have been had the new discovery not been made.

The Velociraptors in Jurassic Park III sported crests of feathers in keeping with discoveries made since the filming of the first movie. Making this change in the raptors appearance would also support the "Birds are descended from dinosaurs" theory that was prevalent in all 3 movies. It is likely that all dromaeosaurids (fierce, sickle clawed, meat-eating dinosaurs, capable of hyper-extending their second toe) had a protofeather coating and probably also displayed feathers.7


DID DINOSAURS HAVE FEATHERS?


More recent fossil finds indicate "yes", some dinosaurs did have feather-like structures.
Sinosauropteryx
(121-135 mya) is the first theropod dinosaur fossil found in China that showed evidence of having feathers (albeit primitive).
Two other "fossils from China's Yixian Formation strengthen the case that some dinosaurs wore feathers long before the first bird ever flew. A find just announced by Chinese and American scientists in the journal Nature preserves a small, long-limbed, raptor-like theropod sprawled on a slab of rock. Arrayed around the dinosaur's head, body and tail are the impressions of filaments — single fibers, longer bundles and tight bunches on the arms that form a herringbone pattern. Only feathers have a similar tufted structure in vertebrates, but since feathered dinosaurs didn't fly, their coating may have kept them warm and energetic".8
These fossil finds from the western part of Liaoning Province, northeast China, reinforced the belief that birds evolved from small, meat-eating dinosaurs, similar to Velociraptor. Protarchaeopteryx robusta (121-135 mya) had obvious dinosaur features but recognizable feathers on its tail. Caudipteryx, (which means "tail feather”, 121-135 mya) looked like a a fast-running theropod dinosaur but its body was covered with feathers.
None of these dinosaurs could fly. It is proposed that the feathers were for the purpose insulation only. These dinosaurs had symmetrical feathers, indicative of flightlessness, where as birds that fly have asymmetrical feathers.


ARE DINOSAURS ALIVE TODAY AS BIRDS?


Many references to birds having descended from dinosaurs were made in the Jurassic Park films. I especially liked the scene at the end of Jurassic Park III; the one where the pterodactyls are flying away from the island. I am sure it did not only symbolize their freedom to colonize elsewhere but it was also an analogy of moving on and forward in life and time, flying like birds, maybe becoming birds.

In Jurassic Park I, the end had a similar effect but, in that movie it was actual birds, i.e. sea gulls. I still perceived the analogy between them and their evolution from dinosaurs.

What is the belief of the scientific community on this issue? From almost all of my reading I got the distinct impression that the evolution of birds from dinosaurs, specifically the theropod branch of birdlike dinosaurs known as Maniraptora ("Seizing Hands"), probably something similar (though not identical) to a small dromaeosaur, is not a highly disputed theory but rather an accepted one.
"Bird-like" dinosaurs include: Velociraptor and Oviraptor from Mongolia.

In the 1800's naturalist Thomas Henry Huxley first noted the similarity between dinosaurs and birds. Then in the 1970's, renown paleontologist John Ostrom meticulously compared the anatomy of Archaeopteryx with the theropod dinosaur Deinonychus, found 22 similarities and concluded that dinosaurs did not become extinct but rather existed today as birds.
"In 1986, J. A. Gauthier looked at over 100 characteristics of birds and dinosaurs and showed that birds belonged to the clade of coelurosaurian dinosaurs. [Gauthier, J.A., 1986. Saurischian monophyly and the origin of birds, in The Origin of Birds and the Evolution of Flight, California Academy of Sciences Memoir No. 8]".9

Scientists note over a hundred characteristics shared by dinosaurs and birds.
Here are but a few:

Half-moon-shaped, swiveling wrist bone: necessary for "flapping flight"
A foot that has 3 toes, facing forward
A wishbone
Skull bones that are air-filled
Hollow, thin-walled bones
S-shaped curved neck
Air sacs running through sinuses in the skull
Large orbital (eye) openings
Five or more vertebrae incorporated into the sacrum (This hip similarity between birds and dinosaurs is most often noted and quoted when comparing an evolutionary relationship between the two).
Similar eggshell structure, microscopically

The characteristics above as well as additional similarities not mentioned here can be found at: Are Birds Really Dinosaurs?
and Dinosaurian Synapomorphies Found In Archaeopteryx.

Some scientists admit the possibility that dinosaurs and birds both evolved, albeit along separate paths, from a yet undiscovered ancestor. There is no scientific discovery to support this theory at this time and most experts believe that "dinosaurs" share the characteristics we see in modern birds.
"...Paleontologist Hans-Dieter Sues of Toronto’s Royal Ontario Museum and a member of National Geographic’s Committee for Research and Exploration says... 'Only dinosaurs are anatomically suited to be the precursors of birds'."10

Read More:
DINOSAURS and BIRDS
Maniraptora ("Seizing Hands"): Birds and Their Closest Relatives
FEATHERED CREATURES FROM CHINA BOOST DINOSAUR-BIRD CONNECTION, National Geographic, June 23, 1998.
Did Birds Evolve from the Dinosaurs?

For an interactive experience, go to this site: Are Dinosaurs Alive?


THE PTEROSAURS OF JURASSIC PARK III


PTERANODON means "wings without teeth". However, avid Jurassic Park III viewers may recall a scene in which a Pteranodon opens its mouth wide, revealing ominous rows of teeth.
Its wingspan averaged 20-25 feet and it stood about 6 feet high. They had hollow bones, small bodies and may have had fur.

As for swooping down and carrying off a 12 year old boy? A child that age would weigh considerably more than a pteranodon. A Pteranodon weighing around 35 pounds would have difficult time flying with such weight in its mouth.11

The whole wing "flapping versus gliding" issue is debatable. Even Alan Grant had stated that a pterodactyl uses its wings for gliding. Yet, we see flapping to gain height in Jurassic Park III.
"Pteranodon was almost certainly a soaring animal; it used rising warm air to maintain altitude; a common strategy among large winged animals (among birds, albatrosses and vultures are adept at soaring). Its scooplike beak was used for snapping up fish as it soared over the oceans that it nested by. A good modern analog for Pteranodon would be the pelican".12

Here is a site devoted to just when "Flapping Flight" came to be: THE ORIGIN OF FLAPPING FLIGHT IN BIRDS

Read More:
Pterosaur F.A.Q.s
PTERANODON "Winged and Toothless"
Introduction to the Pterosauria: the flying reptiles


TRAVELING IN HERDS


In Jurassic Park I, Dr. Grant exclaimed, upon seeing his first dinosaurs, "They do move in herds!"
In the 2 subsequent movies, this fact is taken for granted and shown several times with different species. Did dinosaurs congregate together or were they solitary creatures?

The fossil record shows that dinosaurs did move in groups.

1. Fossils of many dinosaurs, that all died at the same time, were found together at the same location.
2. Trackways (fossil footprints) display multiple animals traveling together.
3. Groups of fossilized nests, of more than one female dinosaur, have been found in a single location.

Why would they move in groups? One reason could be "safety in numbers", in other words, protection from predators. Evidence shows that especially the plant-eaters traveled in herds, nested near each other, ate and migrated together. Fossils of Maiasaura, that were buried in volcanic ash along with their nests and eggs, have been found in groups of 10,000 animals or more!
Another reason could be to maximize the hunt and to work together as seen in Jurassic Park III when the raptors hunted as a trio (two to distract the prey and one to charge).


NESTS WITH DINOSAUR EGGS


Quite a fuss was made in Jurassic Park III over the existence of a nest of Velociraptor eggs. Dr. Grant was fascinated by them and the significance they held. Now he was certain that dinosaurs had both a nesting and nurturing instinct for their young. Billy was so taken with the nest that he wanted to grab a couple of eggs to take back with him.

Did dinosaurs lay eggs and did they care for their young?

John Horner of the Museum of the Rockies in Bozeman, Montana, discovered a large nesting site of hadrosaurs on "Egg mountain". The fossil site included nests with broken eggshells, looking as if they had been trampled over by baby dinosaurs that had NOT left the nest immediately but rather remained for awhile. From this, one can infer that the mother dinosaur cared for the young, bringing them food, much as birds do today.

For those who like interactive websites, there is National Geographic's: Dinosaur Eggs


THE ENVIRONMENTAL SETTING OF THE JURASSIC PARK MOVIES


Realistically, an isolated tropical island could never support the nutritional requirements of all the dinosaurs featured in a Jurassic Park setting.
One can only imagine what an entire herd of Brachiosaurus would do to the flora on a single island! Trees would be stripped of foliage and could never rebound quick enough to support the population that denuded it. Plant-eaters would fail and their populations decrease. Meat-eaters would then begin to suffer the effects of herbivore decline.
Consider also, the fact that dinosaurs were used to eating specific kinds of food. Would they even adapt to a tropical island with vegetation not present at the time they originally lived? Would Jurassic plants have to be cloned also in order to feed the growing population of dinosaurs on the island?
In short: there would be too little food, not the right kind of food, and too much competition for what little food that was available. Unless dinosaur populations were controlled, food artificially replenished somehow and the dinosaurs truly unable to reproduce (as was the original plan in Jurassic Park I), a dinosaur theme park could never work.

Another consideration is a dinosaur's lack of resistance to viruses and bacteria living today. Unless they were able to adapt quickly to an environment quite different from the one that existed 65 million years ago, dinosaurs would surely sicken and die.
Even in our modern world, primitive tribes lost large percentages of their population after being visited by "civilized people" who exposed them to germs they had never come in contact with before.

One last thing to consider is how we would keep the dinosaurs on that island and prevent them from ever leaving. Remember the disasters in the second film (The Lost World) when greed got the better of the human race and T.rex was brought right into the arms of civilization? Remember the end of Jurassic Park III as the pterodactyls are flying away from the island to destinations unknown.
If "life finds a way" how could one be sure that evolution would not provide a dinosaur with a way to get off the island and travel elsewhere even if it were a baby dinosaur hijacking a ride on a log floating to a nearby island?


COLD-BLOODED (Ectothermic) OR WARM-BLOODED (Endothermic)?


In each Jurassic Park movie, references are made concerning the "new discoveries" that dinosaurs were warm-blooded (endothermic) creatures and not cold-blooded like reptiles living today. Dinosaurs as cold-blooded reptiles was the accepted norm by the entire scientific community for a very long time and still is for many scientists despite new theories proposed by paleontologists such as J. H. Ostrom and Robert Bakker.

The late Loris S. Russell originally proposed this theory in 1965 in the paper: RUSSELL, L. S. (1964). Cretaceous non-marine faunas of northwestern North America. Life Sciences Contrib. No. 61, pp.24. Royal Ontario Museum.
Robert T. Bakker, in 1968, published an article in Discover Magazine entitled "The Superiority of Dinosaurs," which mentioned the idea of endothermy.13
Then Ostrom, J.H. published (1969) Terrestral vertebrates as indicators of Mesozoic climate. Proc.North Amer.Paleontl.Conv. pp. 347 - 376.
"This idea continued with Bakker, R.T. (1971) Dinosaur physiology and the origin of mammals. Evolution, 27, pp 636 - 658, and advocated in articles and book, see Bakker, Robert, (1986) The Dinosaur Heresies".14

Slow, sluggish and stupid reptiles were now becoming quick, agile and intelligent "dinosaurs", a class of their own and no longer "reptiles".

Arguments for warm-blooded dinosaurs:

A fossilized Thescelosaurus, a late Cretaceous plant-eating ornithischian, found in South Dakota in 1993, had a 4 chambered heart and a single aorta. Warm-blooded mammals living today have 4 chambered hearts and existing reptiles have a three-chambered heart and paired systemic aortas . So, perhaps Thescelosaurus was warm-blooded and, if so, then maybe other dinosaurs were, too. Ornithischians are theorized to be possible ancestors of birds (saurischians). Birds are warm-blooded.

Cold-blooded animals have a difficult time surviving in cold climates. According to fossil finds and their locations, dinosaurs did survive and thrive in colder climates.

"Horner, for example, has studied microscopic features of bone tissue that can reflect the differences in growth rates between warm- and cold-blooded animals. Fast growth generally requires a speedy, warm-blooded metabolism. And blood vessels create many more spongelike spaces in fast-growing bones than they do in slow-growing bones. Horner's studies of fossil bones suggest that even the most sluggish species of dinosaur had growth rates similar to those birds, which are warm-blooded".15

Analyses of oxygen isotopes in dinosaur bones indicate a warm-blooded metabolism. Oxygen isotope (gl) values, preserved inside bones are a record of the temperatures at the time which those bones formed. "Some saurichian (gl) dinosaurs (such as Tyrannosaurus Rex) and some ornithischian (gl) dinosaurs have produced oxygen isotope values which indicate very low levels of temperature variation", evidence of warm-bloodedness in these dinosaurs.16

Many warm-blooded animals have thermoregulatory features such as hair, feathers or body fat for insulation. Many theropod dinosaurs had feathers and not for the purpose of flight.

"In January 1999, U.S. and Italian researchers used ultraviolet light to peer inside the chest of a fossil baby dinosaur and found its organs were laid out like a bird's or mammal's".17

According to Robert Bakker, dinosaurs had to be endothermic because:

1. Dinosaurs ran fast as was indicated by their leg structure.
2. Predator to Prey ratios indicate dinosaurs were warm-blooded, meaning the ratio of dinosaur predator to prey was 1 to 100, according to Bakker. This would be less so if they were ectothermic creatures.
3. Dinosaurs grew fast as evidenced by studies of their bones. Cold-blooded animals grow much more slowly.
4. Dinosaurs ate a lot. By studying their fossilized jaws and teeth, it becomes evident that dinosaurs could ingest a tremendous amount of food.

Arguments against warm-blooded dinosaurs:

Cold-blooded animals rely on the temperature from their environment to regulate their own body temperature. A modern-day lizard basks on rocks in the midday sun to warm its body and raise its body temperature. This is necessary for the lizard's metabolic functions, including the ability to digest its food.

Some dinosaurs had a heat regulating apparatus on their bodies such as a huge sail-like fin on their back (Spinosaurus) or a series of stakes (Stegosaurus) and these may have been used to collect and evenly disperse heat throughout the body. Such physical characteristics, necessary to regulate body temperature, would imply cold-bloodedness.

John A. Ruben's study of the fossilized internal organs belonging to a Scipionyx samniticus (a Cretaceous theropod; circa about 113 mya), reveal similarities between it and modern crocodilians rather than birds, so Scipionyx may have been cold-blooded. Science; January 22; 283: 514-516 (1999).

"Dinosaurs fail in one test that would be definitive proof according to John A. Ruben of endothermy. Computerized tomography (CT) scans of several hadrosaurs and theropods failed to show the presence of turbinites. Turbinites are thin, scroll-shaped bones or cartilage in the nasal passages of almost all modern endotherms. Covering these, a moist mucus membrane helps humidify air drawn in. When the animal exhales the vital function is found to be the dried-out mucus in the nose that then absorbs water vapor, keeping it in the body (which explains, in part, how a camel can go for long periods breathing dry desert air between drinks of water)".18

Contradicting Jack Horner's observation about dinosaur bone structure being endothermic (see above) : Bones of ectothermic animals tend to have a growth ring pattern whereas endothermic animals have tiny blood vessels as part of their bone structure. Most dinosaur bones resemble an ectothermic structure.

"As endothermy is not present, neither in the tuatara and lizards, which descend from the group of diapside reptiles from which the archosaurs originated, nor in crocodiles, the only recent archosaur, it seems little likely that the archosaur-ancestors of the dinosaurs possessed this quality. And it seems unlikely that it evolved independently in all the groups of dinosaurs, as there is no reason to think that they all had an urgent need to evolve endothermic homeothermy. This does not, however, exclude that some degree of endothermy might have evolved in some groups of dinosaurs, and it is more than likely that it was present in those bird-like dinosaurs of Cretaceous which derivated from the avian lineage at a stage when warm-bloodedness was obtained".19

A Little of Both-Some Cold and Some Warm: Some scientists will allow the possibility that although dinosaurs were cold-blooded some indeed may have been warm-blooded such as the bird-like dinosaurs, Velociraptor perhaps, as stated above and in the paragraph which follows.

"Dinosaurs evolved from cold-blooded animals (the reptiles) and evolved into warm-blooded animals (the birds). All dinosaurs, however, were not the same, and perhaps their physiologies differed also. The huge dinosaurs and the tiny dinosaurs might have used different heat-regulation strategies, just as they used different strategies for other aspect of living. A good argument for this is found among modern mammals. Although warm-blooded, there are some mammals (monotremes, the egg-laying mammals like the duck-billed platypus) whose metabolisms are close to being cold-blooded".20

"At least one expert has speculated that dinosaurs were an intermediate between cold- and warm-blooded animals, and Ruben has proposed that they mixed attributes of both metabolic styles in a unique physiology that ultimately went nowhere".21

Playing both sides and meeting in the middle is the theory of gigantothermy or mass homeothermy.

A quote summarizing mass homeothermy is as follows:

"As animals get larger they have less surface area - skin area- relative to their volume, so they loose less heat to their surroundings. ... So, the suggestion is that because of the large body size of most dinosaurs, they were able to keep warm just by being large. This is called gigantothermy or mass homeothermy." "Mass homeothermy can provide a mechanism for temperature regulation (within one degree, if the outside temperature only varies from 22-32 degrees C daily) without the considerable requirements of a high metabolic rate. However, juvenile and the few small dinosaurs would have to have had a different thermoregulatory (gl) mechanism. Because mass homeotherms cannot cope if the temperature is too low, it has been suggested that dinosaurs became extinct because of climatic change making their biological processes break down". 22

Review the following page for a more concise explanation of this theory: Gigantothermy.

The issue of whether dinosaurs were ectothermic or endothermic remains controversial and is constantly under debate with each new and different fossilized species that is discovered.

Read more:
The Warm-blooded Dinosaurs?
Dinosaurs: Warm or Cold-Blooded?
HOT-BLOODED OR COLD-BLOODED?
Were Dinosaurs Warm-Blooded? Discover, Dec, 2000 by Karen Wright


DINO DNA: CAN WE REALLY BRING BACK DINOSAURS?


In a word, "No". They are extinct and extinction is forever. Here are some reasons why we cannot bring back the dinosaurs.

Even though amber preserves specimens, such as insects, quite well, in order to use DNA in any kind of fertilization or cloning experiment or technique, the DNA must be intact. There cannot be missing pieces to the DNA strand because these cannot be repaired with portions of another specie's DNA. DNA does, in fact, degrade over time, even in amber.

Consider this situation: Today, when police detectives attempt to solve a "cold case" using blood and human secretions taken at a crime scene that occurred many years ago, the DNA in the sample is often too degraded to perform standard tests and pathologists must use Mitochondrial DNA tests instead.
Dinosaur DNA that is at least 65 million years old would be too degraded to use with any kind of fertilization or cloning techniques modern technology has available at this time.

Even if the dinosaur DNA could be extracted from an insect preserved in amber, the extraction would have to be 100% perfect and pure, with no mixing of the dinosaur DNA and that of the insect.

Scientists could not work with a DNA chain that has any gaps. Another species cannot be use to repair broken chains. So, frogs could not be used to repair dinosaur DNA.

Even if, hypothetically, dinosaur DNA could be found intact and in pristine condition, implantation must be in a viable and living egg. Since there are no living dinosaurs we would not have compatible egg and cytoplasm in which to implant genetic material.

Read more:
Are Movies Science? Dinosaurs, Movies, and Reality , Dino Buzz, Current Topics Concerning Dinosaurs


THIS WRITER'S PERSONAL NOTE


All this having been said, while I seek to know truths and thrive on learning new things, when I watched all 3 Jurassic Park movies I was like a kid again. I was enthralled with the realistic-looking dinosaurs, caught up in a world I briefly thought might exist again one day with newer technologies and thrilled by the very idea that dinosaurs may have behaved as they did in the films.
Trained in science, I present the facts. And, these 3 movies are the source of many online dissertations as to the veracity of the scenes the viewer experiences. But, all the facts in the world will not detract from the enjoyment of people who have, for a short time, allowed themselves to be transported to a long extinct environment filled with amazing flora and fauna that will never be seen again. It's all about imagination. And, without that, we a just plain stuffy and boring!

So, let the film producers stretch the facts a little. Entertain us! Wow us!
In the end, they will create a film that will be the focus of many online debates. Who cares? For a time, let us not be so pedantic.
Oh the wonderment of "children" of all ages, including myself, as we sit in our movie theater seats watching the dramatic presentation made possible by the creative intelligence and imagination of our species!


Something to think about, incidental and not integral to this paper:
Animals get bigger and bigger and then get too large, and die out. (Cope, 1800)

Hasn't our species gotten larger over generations?





References and Credits:

Spinosaurus Fact Sheet
Tyrannosaurus rex Fact Sheet

T.rex's Diet
Tyrannosaurus: Hunter or Scavenger?
Inferring the Possible Speeds of Dinosaurs?
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"Jurassic" Scientist is Back and Consulting on Part 4
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Jurassic Park III Movie Goofs
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When Dinosarus Roamed America: Latest Discoveries; Discovery.Com
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FEATHERED CREATURES FROM CHINA BOOST DINOSAUR-BIRD CONNECTION National Geographic; June 23, 1998
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Sinosauropteryx prima
DINOSAURS and BIRDS
Maniraptora ("Seizing Hands"): Birds and Their Closest Relatives
How smart was Velociraptor?
Are Movies Science? Dinosaurs, Movies, and Reality

Are Birds Really Dinosaurs?
Dinosaurian Synapomorphies Found In Archaeopteryx
The link between dinosaurs and birds By Ken Howard Wilan, The Boston Globe, August 25, 2005
Did Birds Evolve from the Dinosaurs?
The Warm-blooded Dinosaurs?
THE ORIGIN OF FLAPPING FLIGHT IN BIRDS
The Warm-blooded Dinosaurs?
Dinosaurs: Warm or Cold-Blooded?
HOT-BLOODED OR COLD-BLOODED?
Were Dinosaurs Warm-Blooded? Discover, Dec, 2000 by Karen Wright
A Theory That Doesn't Fly, Scientific American, February 01, 1999
The Evolution of Flight
An adaptive scenario for the origin of birds and of flight in birds
Dinosaurs Were Warm-Blooded
Oxygen Isotopes What can oxygen isotopes tell us?
Gigantothermy
Comments to " Warm-blooded Dinosaurs?"
Hot and Cold Running Dinosaurs
Were dinosaurs ectotherms (cold-) or endotherms (warm-blooded)?
Key Dinosaur Characteristics, Dr. George Johnson's Backgrounders, page 3
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Dromaeosauridae
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Dilophosaurus, the Actor
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Long-necked dinosaurs didn’t munch on tall trees, by Steven Hunt, April 30, 1999, Discovery, Science Today

As of writing this paper (9/05), all of the above reference links were active and fully functional.
They will, however, not be maintained.

09 September, 2005
L. Immoor
BA, MA
Hofstra University
Hempstead, New York
Earth Sciences, Geology


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See also: The Good and Bad Science in Popular Sci-Fi Movies