Mamenchisaurus is a very large sauropod dinosaur in the family Mamenchisauridae which lived in the Late Jurassic during the Oxfordian to Tithonian ages, around 160 to 145 million years ago. Its name was intended to mean “Mamenchi Ferry reptile” in reference to the location where it was discovered in China; this is actually a misspelling, as it should be “Mamingchi” rather than “Mamenchi.” Despite this error, the rules of taxonomy mandate that the name remains as it is. This is one of the largest dinosaurs known, reaching lengths in excess of one hundred feet.
The first fossils of Mamenchisaurus were discovered in 1952 during the construction of the Yitang Highway in Sichuan, China. Despite the fossil being incomplete (and the neck incomplete as well), it was studied by paleontologist Professor Yang Zhongjian (more widely known as C. C. Young) and named in 1954. He recognized at the time that this animal would have been 13 to 15 meters (43 to 49 feet) in length; it was named Mamenchisaurus constructus, due to the fact that it was found at a construction site. He meant to name the dinosaur’s genus after the river where it was found, but mistakenly identified it as Mǎménxī (meaning “horse-gate brook”) instead of Mǎmíngxī (meaning “neighing horse brook”).
In 1972, Young was involved with the discovery and naming of a new species, Mamenchisaurus hochuanensis, which was somewhat smaller but had a more complete neck. This allowed paleontologists to estimate the length of the dinosaur’s neck, realizing that it was longer than that of any other animal known.
In 1987, a third species was discovered. Mamenchisaurus sinocanadorum has a specific epithet which references the collaborative efforts of Chinese and Canadian paleontologists that led to its discovery, and it was named in 1993 by paleontologists Zhong Zheng and Dale Allen Russel. This is the largest known and best-studied species of Mamenchisaurus, and was found in the Shishugou Formation within the Junggar Basin of the Xinjiang Province.
More species would be discovered in later years. Mamenchisaurus youngi was named in 1996, followed by M. anyuensis later that year and M. jingyanensis in 1998. Most recently, M. yunnanensis was named in 2004.
Mamenchisaurus was a member of the family Mamenchisauridae, and the infraorder Sauropoda. This particular species was found in the Shishugou Formation in Xinjiang, China. Material of this species includes a partial skull and skeleton. Some theories have been presented to explain the abnormally long neck (in comparison to other sauropods), including sexual selection, or competition with other sauropods and herbivores.
Because this species of Mamenchisaurus was not named until 1993, it is likely that InGen may have assigned it to a different species within that genus, meaning it would have been classified incorrectly until after the 1993 incident. InGen cloned this species on Isla Sorna sometime in the late 1980s or early 1990s, but there is no evidence that they were ever intended for use in Jurassic Park.
This sauropod is 35 meters (115ft) in length, 8 meters (26ft) in height and 25 tons in weight. It has one of the longest necks of any living animal at almost 15 meters (49ft). The neck is held erect, with the comparatively tiny flat head typically seen looking downward when traveling; the nostrils are placed high on the skull, which may be a phenotypic error in InGen’s specimens. The tail is equally long, held parallel to the ground. This tail tapers to a point. There is some evidence in the fossil record (from the closely related Mamenchisaurus hochuanensis) that the tail may have ended in a club or sensory organ, which is absent in this animal. It is not known if this adornment was removed by InGen’s geneticists in the development process or if M. sinocanadorum naturally lacks it. The hunched back, on the other hand, is almost certainly the result of genetic engineering.
As with all sauropods, this creature is a quadruped and has powerful column-like legs. On the rear feet, this animal has small toes giving its feet a rounded shape. The front feet have slightly larger toes, most notably the innermost toe on each foot; this toe ends in a large claw, the function of which is currently unknown. It is generally believed that the front feet would normally be fleshier, to the point where only the innermost toe would be visible at all. InGen’s sauropods either have longer toes or less fleshy feet than their ancestors.
Coloration of this species is fairly subdued. They are an earthy gray-green color over the entire body, with minimal countershading on the underbelly. Yellow-brown striping and spots can be seen over most of its body, but the neck is the most colorful region, with slightly more vivid yellow patterning from the shoulders to the head.
Hatchling and juvenile stages of Mamenchisaurus have not been observed.
In a deleted scene from the script of The Lost World: Jurassic Park, a mating pair of Mamenchisaurus is observed, implying that a male and female would appear in the film. However, the sexes of the animals which actually were seen are not known. They do not exhibit any noticeable differences, so if a male and female do appear as implied in the script, this species lacks distinct sexual dimorphism.
Mamenchisaurus has only been observed on the edge of a pine forest near a game trail. The trees in its habitat easily reach heights that it could comfortably feed from.
As of InGen’s last count of the animals in 1993, there were four Mamenchisaurus living on Isla Sorna. Two adults were observed during the 1997 incident in the island’s northeast; the film’s original script implies that they also could be found in the forest slightly farther south.
Animal populations on Isla Sorna became extremely stressed due to resource scarcity around the turn of the millennium, causing mass death events. In 2004, any surviving Mamenchisaurus were collected by InGen under Masrani Global Corporation and moved to Isla Nublar. At the moment there is no direct evidence of this dinosaur living anywhere within the Muertes Archipelago.
In late 2004, all surviving Mamenchisaurus were transported to Isla Nublar. After several weeks in quarantine, they were most likely kept in habitats located in Sector 5. Population statistics for the period of time between 2004 and 2018 are not known. There is no evidence that they were ever intended for use within Jurassic World itself.
A statement released by the Dinosaur Protection Group on February 4, 2018 implied that Mamenchisaurus may have become extinct on the island.
Mantah Corp Island
During the 2000s and 2010s, InGen rival Mantah Corporation built a facility for animal testing on Mantah Corp Island which they populated with species illegally acquired from InGen. There is, at the moment, no evidence that Mamenchisaurus was among the species they obtained.
BioSyn Genetics Sanctuary
After the release of de-extinct animals into the wild in the summer of 2018, various governments permitted BioSyn Genetics to capture and contain problematic animals. The largest containment facility used by the company was the BioSyn Genetics Sanctuary, which operated during the early 2020s. Since no living Mamenchisaurus have been confirmed in recent years, it is unlikely this was among the species housed there.
It is possible that hatchling or juvenile Mamenchisaurus could have been removed from their habitats due to poaching between 1997 and 2018, but there is no direct evidence for this species specifically being moved to any site not under InGen control.
Genetic samples may be the only form in which this species persists. If its DNA is being illegally traded, there is a good chance it may be found in the Amber Clave night market in Valletta, Malta. Failing this, one could probably at least find a person capable of tracking down a sample of Mamenchisaurus genetic material.
While several species of Mamenchisaurus existed during the late Jurassic period, M. sinocanadorum specifically evolved approximately 161 million years ago. It, like its kin, lived in central Asia. The region where it lived was a lush woodland supported by expansive lakes and rivers. This species became extinct approximately 159 million years ago, having existed for a fairly short time; some of its relative species lived until as recently as 114 million years ago. Only M. sinocanadorum would ever return, though, being cloned from genetically-modified samples toward the end of the twentieth century.
At the moment, there is no evidence for wild populations establishing outside the Gulf of Fernandez at any point. This gargantuan creature may be globally extinct.
Behavior and Ecology
Mamenchisaurus has only been observed once, in the early afternoon. At the time, two animals had emerged from the forest and were actively traveling along the game trail, though they may have been disturbed by the activity of InGen’s hunter expedition.
A deleted scene portrays these animals engaging in mating behavior earlier in the day.
Diet and Feeding Behavior
As with all sauropods, Mamenchisaurus is herbivorous, and most likely fed on the tall pine trees which grew in its habitat on Isla Sorna. Due to its size, most other species cannot compete with it as an adult; it can reach the highest branches where only other sauropods are able to challenge it for food. Specifics about how it feeds, or what plants it favors, are not currently known. However, in order for the animal to survive after Hurricane Clarissa, it would have had to feed on lysine-rich plants in order to combat the lysine contingency. Some of the lysine-rich plants known to live on Isla Sorna include soy and agama beans.
It is susceptible to bracken poisoning in the game Jurassic World Evolution, suggesting that it feeds on bracken ferns. This game also demonstrates its favored food being tree ferns. It will also feed on conifers and ginkgoes, but its digestive system is not designed for pawpaws, mosses, or horsetails.
Mamenchisaurus do not appear to be extremely social. A mating pair is portrayed in a deleted scene, while a pair of adult animals has been sighted on Isla Sorna. Little is known about how these animals interact with each other, though they are known to wave their whip-like tails through the air when traveling together. This may be a form of visual communication, though it is not confirmed as such.
The game Jurassic World: Evolution portrays this animal as being comfortable in pairs or in groups of up to four, but no more than this. Such population levels are consistent with InGen documentation stating that only four animals had existed in their facilities.
Mating behavior in Mamenchisaurus sinocanadorum is explicitly described in a deleted scene from the script of The Lost World: Jurassic Park. As it has not appeared in the films or been confirmed as canon by any official source, its reliability is questionable.
In this scene, one animal makes a “furtive” honking sound to get the attention of its partner, which raises its head above the tree line and approaches the first animal. They intertwine their necks as a form of courtship and get into a mating position; like modern birds, the act of mating itself lasts mere seconds. During this brief copulation, they both whip their tails around to make loud snapping sounds. Sexes of the animals in this scene are not identified, leaving the behavior of the male and female in particular unknown. The perfunctory nature of the courtship preceding copulation suggests that these animals were already a mated pair, raising the possibility of long-term pair-bonding.
As with all dinosaurs, the Mamenchisaurus would lay eggs to reproduce. A clear view of the pubic area of Mamenchisaurus reveals no visible external genitalia. This suggests that the sex organs of this sauropod are contained within a cloaca, as is the case in most other dinosaur species. Whether the male has an intromittent organ which can be extended for copulation is currently unknown, but this is the ancestral condition in amniote animals, and was the case in the earliest birds.
A Mamenchisaurus cloaca is explicitly depicted in the arcade game released for The Lost World: Jurassic Park. As with modern birds, the animal also uses its cloaca to defecate.
Sauropod eggs are nearly spherical and typically fairly large. According to InGen research and paleontological evidence, the largest egg clutches produced by dinosaurs contain about twenty-one eggs, but the clutch size of Mamenchisaurus is unknown. The biggest dinosaurs usually have incubation periods close to a year.
This dinosaur is not particularly vocal, but may be heard making low-pitched resonating groans and faint wailing noises. The meaning of these sounds is not known; they were heard while a large stampede of smaller dinosaurs was passing by the mamenchisaurs. In a deleted scene, the mamenchisaur mating call is described as a “furtive honk,” and they use their tails to make snapping sounds.
Non-vocal communication is also possible using the motion of the tail. One animal was seen waving its tail dramatically when in front of another member of its species while they were on the move.
The game Jurassic World Evolution keeps this animal as relatively quiet, and maintains its range of low-pitched groans and wails that the film portrayed.
Despite its relatively asocial nature as a species, Mamenchisaurus is highly tolerant of other animals living in its habitat. This is, most likely, due to the fact that few other animals can compete with it for food sources. It has been seen in association with Parasaurolophus, Gallimimus, and Pachycephalosaurus. There is currently no evidence of a mutual symbiotic relationship between these animals, though the smaller dinosaurs could certainly benefit from the protection offered by such massive creatures. On the other hand, InGen’s other tall sauropod Brachiosaurus is only known to have lived on the opposite side of Isla Sorna, suggesting competitive exclusion between these two herbivores.
Species found near known Mamenchisaurus territory, but not directly seen to associate with them, include the herbivores Stegosaurus and Triceratops, as well as carnivores Compsognathus and Tyrannosaurus. The immense size and powerful tail of the Mamenchisaurus adult would protect it against carnivores. This dinosaur itself is so large that it would affect its environment both through consuming large amounts of plant matter and destroying plants with its movements. Pine trees and redwoods appear to be common in the location where it chooses to live in the wild.
It is portrayed as feeding on bracken ferns as well as trees in Jurassic World Evolution, and the game also portrays the animal as being unaffected by the common cold virus.
While this is a somewhat obscure dinosaur (mostly known for the extreme length of its neck) and not commonly featured in popular culture outside of dinosaur encyclopedias, its name is quite meaningful. While its genus name is a mistransliteration of the Mamingchi Ferry, the name of this particular species (M. sinocanadorum) is a celebration of international collaboration in science. It translates very loosely to “China/Canada,” referencing the countries from which the paleontologists came to discover one of the longest dinosaurs ever found. Such naming was certainly deliberate and this impressive dinosaur stands as a testament to what comes of cooperation.
Unfortunately no successful efforts at keeping Mamenchisaurus in captivity have been reported. There is no evidence of it being intended for Jurassic Park, though since InGen did keep it alive the possibility of it eventually being put on exhibit was not off the table. Some concept art of sauropods in Jurassic Park: San Diego has been seen, but no attempts to capture this dinosaur in 1997 were reported. Then, when it was brought to Isla Nublar for safekeeping in 2004 or 2005, it does not appear to have ever been shown in Jurassic World. The massive food and habitat needs for such a large animal may have presented difficulties in housing it, especially with two other sauropods (Brachiosaurus and Apatosaurus) already on display in the park.
Were it eventually housed in captivity, its needs would probably be similar to other sauropods, but with accommodations for its enormous length and small social group size.
Several species of Mamenchisaurus are known, with M. sinocanadorum being the longest and one of the lengthiest animals ever discovered. Some taxonomists doubt that all currently-known species are legitimate, and that some may be synonymous with previously-named Mamenchisaurus species. Since the fossil remains are often fragmentary, they are difficult to classify reliably. In fact, the classification of this dinosaur’s closest relatives is also debated. They were previously classified in the subfamily Omeisaurinae, which some scientists still use, but most paleontologists now consider them to belong in a clade within the family Mamenchisauridae (or alternatively, Euhelopodidae).
Since bringing this species back from extinction, InGen would have been able to perform genetic research to potentially shed more light on the relations this dinosaur has within the tree of life. Unfortunately no information is currently available. Because it was abandoned in 2015 and has since probably become extinct, research is indefinitely on hold.
After the incident at Jurassic World in 2015 caused the park to close, this species was able to roam Isla Nublar as it pleased, but was no longer provided for by paleoveterinarians. Animal welfare on the island was a hotly debated topic in international politics through 2018, becoming even more contentious when volcanic activity threatened the well-being of the animals even further. The precise fate of Mamenchisaurus is not known, but an image released by the Dinosaur Protection Group in early February 2018 lists this animal’s genus name in red like those that had become extinct. This implies that the DPG may have believed this dinosaur had died out, which they considered an act of negligent cruelty.
This dinosaur was not featured in any of their public outreach efforts, further suggesting it was already extinct.
InGen may have intended to showcase this dinosaur in any of their de-extinction theme parks, but two failed to open and the third does not appear to have ever exhibited Mamenchisaurus. The reason for it is not known, but it may simply not have been feasible to house a population of a third sauropod species on top of the two they already exhibited, especially when it was so much longer than the other two. While such a gigantic dinosaur would certainly draw crowds, it would not have stood out as much because other sauropods were already in the park. Mamenchisaurus is more obscure than the famous Brachiosaurus and Apatosaurus, and its huge size combined with its preference for small social groups would make it less feasible to keep than the slightly smaller, more social sauropods. However, as long as it lived in the park it could have been used for its dung; sauropod dung was used as fertilizer in Jurassic World’s greenhouses, and such a large species would produce copious amounts.
Due to both its ancient origin and genetic engineering inherent in the de-extinction process, Mamenchisaurus is a source of unique biopharmaceutical compounds. What resources could be derived from its body are not known, however, and since it has probably gone extinct they will remain unknown until it is cloned once more.
Mamenchisaurus is not usually considered dangerous and no attacks on humans have been reported. Sauropods are stereotyped as “gentle giants” because they are not aggressive toward human beings despite their huge size making them quite capable of killing a person. In reality, their non-aggression is because of their large size. Adults might not even notice a human, let alone feel threatened by one. We are simply too small for them to bother with. They are better off saving their energy for fighting off predators that are big enough to harm them.
The main known interaction with humans was during the 1997 Isla Sorna incident, during which two adult Mamenchisaurus were briefly alarmed by the InGen Harvester fleet and the stampede caused while assets were collected. During the chase and capture sequence, one Harvester even drove a motorcycle between the legs of one of the Mamenchisaurus to the amusement of himself and his companions. While the dinosaur did not make any attempt to harm him and probably did not even see him until he had moved out from under it, we cannot stress enough that you should absolutely not do this. Even though they have no reason to attack a human, Mamenchisaurus and other sauropods are so large that they could effortlessly crush a person by accident or by instinctive reaction to being startled. If the dinosaur missteps, or kicks you reflexively when your sudden appearance takes it by surprise, you will almost certainly be severely injured or killed. Even if it is deliberately trying to avoid stepping on you, it could be nervous or distracted enough to trip and fall, which would be fatal to an animal so large as well as anyone it landed on.
Its whip-like tail is also dangerous, and a strike from it would rend your skin, break bones, and cleave organs apart. You would in all likelihood die within minutes, if not seconds, of a tail strike. The tail is normally held far above a human’s head level, but is very flexible and could easily swish down to a height that might endanger you. Like with a kick or stomp, it might hit you accidentally, or reflexively if you startle it. Harassing the animal the way the aforementioned InGen Harvester did might also provoke a purposeful reaction, the mamenchisaur acting to remove an annoyance the way you might swat an irritating fly. The tail’s tip moves quite fast and you would probably have little time to react.
In addition, even the normally-indifferent sauropods may become aggressive if they have young to defend. The parenting behaviors of Mamenchisaurus are unknown, but there is some evidence that other sauropods (contrary to common assumption) provide parental care to their own offspring. It is good practice to avoid all baby animals or nesting grounds in the wild.
As a kind of conclusion, there are several ways that a Mamenchisaurus could kill you, and all of them are extremely unpleasant and rapid. It will probably not attack, as no unprovoked sauropod attacks on humans have been reported, but this does not make it safe to be around by any means. Just as you might step on a tiny insect by accident, this is a creature that could crush you to death without even noticing. While Mamenchisaurus itself is most likely extinct, other sauropods are out there in the world and this advice is useful for them as well. Wild animals are unpredictable and your best course of action is always to give them space. Observe these majestic dinosaurs from a distance, and remain out of their way if they are on the move.
Behind the Scenes
In the original script, Mamenchisaurus would have only appeared in a scene shortly after the first Stegosaurus encounter where Hammond’s team observed two mating. In the game trail scene, their role would have been filled by Apatosaurus instead.
The CGI model for this dinosaur was created not from scratch, but by heavily modifying the Brachiosaurus model from the previous film.
Mamenchisaurus – Isla Sorna – four individuals bred by InGen at Site B