Mamenchisaurus was a very large sauropod 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.
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 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. 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 1993, 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 2004 by paleontologists Z. Zheng and Dale Allen Russel. This is the largest known and best-studied species of Mamenchisaurus.
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 discovered until 1993 and not named until 1994, 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 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.
It 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.
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-brown color over the entire body, with minimal countershading on the underbelly. Yellow-brown striping and spots can be seen over most of its gray 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.
Animals of this species from the game Jurassic World: Evolution are confirmed to be female, and show coloration similar to those in the film.
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.
In the game Jurassic World Evolution, this animal is portrayed as having an ideal habitat consist of 15,400 square meters of grassland and 25,400 square meters of forest within its territory.
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 the park itself.
A statement released by the Dinosaur Protection Group on February 4, 2018 implied that Mamenchisaurus may have become extinct on the island.
InGen bred Mamenchisaurus on Isla Sorna sometime between 1986 and 1993. As of June 11, 1993, they were not ready for exhibition in Jurassic Park.
As of InGen’s last count of the animals in 1993, there were four Mamenchisaurus living on Isla Sorna. Two adults were observed on February 21, 1997 in the island’s northeast; the film’s original script implies that they also could be found in the forest slightly farther south.
In 2004, any surviving Mamenchisaurus were collected by InGen under Masrani Global Corporation and moved to Isla Nublar.
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.
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 and get into a mating position; during the brief copulation, they both whip their tails around to make loud snapping sounds. The immense weight of the animals likely restricts the window of time that they have to mate. Sexes of the animals in this scene are not identified, leaving the behavior of the male and female in particular unknown.
As with all dinosaurs, the Mamenchisaurus would lay eggs to reproduce. In Jurassic Park: The Game, various theropods and Triceratops are shown to have cloacae, but this is unconfirmed in sauropods. However, a clear view of the pubic area of Mamenchisaurus can be seen in The Lost World: Jurassic Park, and no external genitalia are visible. This suggests that the sex organs of this sauropod are contained within a cloaca.
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.
Relationship to Humans
As this species is rarely seen, its relationship with humans is mostly unknown. On February 21, 1997, two adult Mamenchisaurus were briefly alarmed by the appearance of InGen’s harvester operation and the stampede caused while assets were collected. However, the sauropods were unharmed during the incident and did not show signs of aggression toward humans. Their large size could make them hazardous to humans, but even when presented with an easy opportunity to do so, they do not attempt to cause any harm. A hunter was able to entertain himself by driving a motorcycle directly between all four legs of one such animal, which made no move to hurt him.
Based on Jurassic World: Evolution, the cost of raising a Mamenchisaurus from fertilization to maturity as of 2018 would be $891,000.
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