Height: 25 feet
Weight: 30 tons
- Adult (both sexes): A brown mottling with lighter brown back striping.
- Juvenile (both sexes): Lighter brown mottling all over.
Diet: Low to medium-growing plants, occasionally also leaves from trees.
Preferred Habitat: Wide open spaces with plenty of vegetation.
Mamenchisaurus has the longest neck of any other dinosaur on Isla Sorna, which at 36 feet, is almost half the length of the entire animal. Its long neck allows the Mamenchisaurus to feed on a variety of low and medium-growing vegetation from a stationary position.
Mamenchisaurus is a gentle giant which tends to avoid confrontation. Although the young are vulnerable to many types of predators, the adults are protected from most carnivores by their great size. Packs of Allosaurus and Giganotosaurus are by far the biggest threat. If under attack, a Mamenchisaurus will try to defend itself by rising up onto its hind legs and falling forward and pounding the ground (or an unfortunate predator) beneath its feet. Like Apatosaurus, Mamenchisaurus will also use its whip-like tail as a weapon.
Mamenchisaurus is sometimes known to travel alongside herds of Styracosaurus for protection against predators such as Allosaurus. Most predators will not attack such a lethal herd of animals, therefore the Mamenchisaurus is usually well avoided. It is not uncommon to see a herd of Styracosaurus encircling a lone Mamenchisaurus as they trek across the landscape.
Mamenchisaurus is much less common than its three other sauropod contemporaries, and is not as noisy. Its most common call is a deep bellow, and typical to sauropods, it also produces infrasounds to communicate with other individuals over long distances.