ANKYLOSAURUS

Ankylosaurus magniventris

Etymology: Great-bellied stiff lizard

Nickname: "Anky" or "Ankylo"

Classification: Thyreophora, Ankylosauridae

Diet: Herbivore

Size: 8 meters long

Provenance: Hell Creek Formation, Montana, USA - Late Cretaceous, Maastrichtian stage, 66 million years ago

Movie appearances: Jurassic Park III (2001); Jurassic World (2015); Jurassic World: Fallen Kingdom (2018); Jurassic World: Dominion (2022); Jurassic World Rebirth (2025)

Ankylosaurus magniventris is a species of ankylosaur thyreophoran dinosaur that lived in North America during the Cretaceous period. It is a very defensive creature, and it is evolutionarily perfected for that. It is not represented by a lot of fossils, even though it represents the largest and one of the youngest ankylosaurid species.

Ankylosaurus is variable in regards to its phenotypical appearance, as it grows, having a dark tan underbelly and bright red patches on the eye region, before it transitions to a broad dull gray-brown appearance as it matures. 

Ankylosaurus are surprisingly social creatures, found to be able to form herds. They can form a defensive circle formation to protect juveniles, for which they care for. It is likely that such a defensive mechanism is an adaptation to the dangerous predators that this species is forced to inhabit with. It has a thick armored skin and it displays behaviors that are effective at deterring predators. These herbivores are also curious animals, living in woodlands, often nudging logs and checking each other out to evaluate the environment that surrounds them. These dinosaurs form surprisingly strong social bonds and social complexity that ensures their survival in their environment.

Ankylosaurus was resurrected in Isla Sorna, and released to the environment; by 2001, the juvenile Ankylosaurus were still alive, residing in the jungles of the northeast side of the island. A small group of them was seen by Billy Brennan and Paul and Amanda Kirby, who were stranded on the island in that year.

In 2015, the Ankylosaurus were residing in Isla Nublar in Jurassic World; they were seen by Zach and Gray Mitchell who existed the gyrosphere exhibit through an opening in the perimeter fence, where these dinosaurs were around. However, one of the Ankylosaurus was hunted and taken down by the escaped hybrid Indominus rex; the corpse of the ankylosaur was later found by the campers of Camp Cretaceous. These campers managed to also tame a young female Ankylosaurus that they nicknamed Bumpy.

After the eruption of Mount Sibo, in 2018, and the release of several dinosaurs on the north american mainland, Bumpy remained a loyal ally to the campers that adopted her, even defending them from threatening carnivores. However, the other feral Ankylosaurus roamed free and their status was instead monitored by the Department of Prehistoric Wildlife (DPW). The DPW, at one point, captures Bumpy with orders to a warehouse to be taken to Soyona Santos. However, Ben Pincus made his best efforts to try and rescue her. Its eventually learned that Bumpy is pregnant, and later she eventually does lay a single large soft-shelled egg.

In 2022, Ankylosaurus remained wild animals, this time found in an additional place, the Biosyn Sanctuary in Italy, where these dinosaurs roam free and interact with the local ecosystem.

FILM vs. REALITY

Ankylosaurus in the films differ from the real life one in some aspects. One of the main differences lie in the organization and shape of the armor. While the movie's counterpart reconstructs the armor plating of Ankylosaurus as being organized in articulated rings, like that of an armadillo, decorated with rows of spikes on the back and sides of the body, the real life one instead has just a covering of very small rounded osteoderms with rows of much larger protruding osteoderms covering the back and sides of the animal, that are not quite as spiky and curved, and more rounded and smooth. Another detail that the real life animal has, that the film counterpart lacks, is the presence of small and sharp osteoderms in its arms too. While the limbs of this animal, in the films, is relatively more columnar in form and shape, the ones of the real life animal were more slender and more in line with the typical arrangement of a more basal dinosaur, with more typical three-toed back feet reminiscent of more bipedal dinosaurs. The tail of the real life animal was very stiffened and slender at the end, not being able to bend and curve at the tip, allowing it to swing its tail club like a baseball bat, a detail not reflected in the films where the tail of the Ankylosaurus is instead depicted with a bendy tail end.

Ankylosaurus is depicted as a relatively agile animal that is able to gallop, but this isn't quite believed to have been done by the real animal. Having a much more stiffened, wide, and shallow heavy body, it is unlikely that it was formatted to gallop, and if it ran, it was probably not a prolongued running, and likely only engaged in slower walking speeds. This slow animal may have been social in real life, judging by fossil evidence of its relatives, showing herd living in adult ankylosaurs, footprints suggesting coexistence between adults and juveniles, as well as creches where juvenile ankylosaurs would be gathering together. This level of herd living is reflected in the depiction of Ankylosaurus in the franchise.