SARCOSAURUS

Sarcosaurus woodi

Etymology: Wood's flesh lizard

Nickname: "Spitter" or "Sarco"

Classification: Theropoda, Neotheropoda

Diet: Carnivore

Size: 3.5 to 4 meters long

Provenance: Blue Lias Formation, UK - Early Jurassic, Hettangian-Sinemurian stage, 200-198 million years ago

Movie appearances: Jurassic Park (1993); Jurassic World: Dominion (2022); Jurassic World Rebirth (2025)

Sarcosaurus woodi was a sizeable basal neotheropod theropod from the Early Jurassic period. It was found in what is today England. It was a fast-dwelling carnivore, reaching up to 48 km/h.

One of its most characteristic traits is its "frill" or "mane" made of filamentous hair-like feathers, as well as specialized glands in its mouth that release a noxious fluid, and an unusually stocky skull that would superficially resemble that of a Deinonychus, if it wasn't for the pair of bony crests on top of its head. The feather frill expands and rattles when the animal is ready to attack. Like all theropods that were resurrected for Jurassic Park, its wrists cannot pronate, leading the hands to face each other when relaxed.

Social behaviour in Sarcosaurus is poorly studied, so much of their ethology is known from solitary behaviour. Documentation for Sarcosaurus population, by the time of Jurassic Park, is unclear, but it is known that at least one was created, represented by a juvenile or small subadult, by 1993. By the little interactions recorded at the time, the Jurassic Park Sarcosaurus appeared to be a rather curious animal that behaved unafraid next to humans, presumably due to its lack of familiarity and interactions with them. When interacting with humans, the Sarcosaurus appeared most fascinated by the movements of the humans themselves, rather than by whatever objects the humans carried with them. The feathered frills of Sarcosaurus are known to be used as a means of intimidation, especially when they feel threatened.

By 1993, the Sarcosaur Paddock was in place in Jurassic Park, but little documented information has been recovered about this enclosure, and it was presumably a very recent addition to the park, but it was otherwise where the Sarcosaurus resided. When Hurricane Clarissa hit Isla Nublar, the resident immature Sarcosaurus stalked Dennis Nedry, who got his vehicle stuck on a fallen tree. Nedry briefly interacted with the dinosaur, appearing to deem it inoffensive, dismissing it as he continued to take care of his vehicle. However, the Sarcosaurus attacked, blinding him with his noxious spit, and following him inside the car, where it procceded to devour Nedry. As Nedry was disembowled and spat at, his Barbasol can containing stolen dinosaur embryos rolled down the hill and was lost in the jungle. Subsequent files recovered by the Dinosaur Protection Group confirmed that there were five Sarcosaurus living in the Sarcosaur Paddock, by 1993, and that they all seemed to have survived by 1994.

When Isla Nublar was reclaimed for Jurassic World, there were no Sarcosaurus being displayed publicly, but the dinosaur was present in the Holoscape, a place in the park's innovation center, where holograms of various dinosaurs were displayed, regardless if these were found in the park. The hologram of a Sarcosaurus was last used in 2015 by a fleeing Zach Mitchell, who was turned on to distract the dangerous Deinonychus Delta, who was chasing him. Seemingly, Mantah Corp held Sarcosaurus in their own secret island, placing them in their swamp biodome. After the shutdown of Jurassic World, the Sarcosaurus, that were being held in their enclosure away from public viewing, were found living in the wilderness, where they appear to have formed packs; instances where humans encountered these dinosaurs resulted in aggressive outcomes, where the Sarcosaurus released their spit in an act of aggresion, while the humans struggled to defend themselves from the sarcosaur pack.

By 2022, a few Sarcosaurus were captured and introduced to the Biosyn Sanctuary, located in Italy. One night, Claire Dearing was being ambushed by a small pack of Sarcosaurus, near a research outpost, and one of them approached her, showing off its feathered frill, though she was saved by Owen Grady. These ones were already adults, so bigger than the individual that infamously killed Dennis Nedry in 1993. Sarcosaurus were responsible for the death of Lewis Dodgson, CEO of Biosyn, who got stuck in the Biosyn Sanctuary's hyperloop, and was cornered by a trio of these dinosaurs, ironically reminding us of Dennis Nedry, who he tasked to retrieve stolen embryos back in 1993.

FILM vs. REALITY

DISCLAIMER: Sarcosaurus does not appear in any of the Jurassic Park films, and it is here just used to plausibly replace the films' Dilophosaurus. The real life Dilophosaurus is different from its movie portrayal in several aspects. Dilophosaurus, in real life, was very large, reaching 7 meters in length, easily being as tall or taller than a man, while the movie's depiction shows this animal as significantly smaller. The skull of the real life Dilophosaurus was very characteristic, showing the presence of a notch on the front part of the upper jaw, while the movie Dilophosaurus has a more uniform mouthline. The crests of Dilophosaurus were also much taller, wider and more vertical, and were probably not very keratinized, being covered in soft tissue, due to it being covered in air sacs, being continuous with the sinuses of the skull, so it would differ from the flat hard crests of the movie counterpart, whose crests also distance from each other at a nearly 45 degree angle.

The real life appearance of Sarcosaurus is harder to determine, due to the incompleteness of the fossil material, so traits like the skull shape, as well as the presence and shape of the crests, are speculative. The movie Dilophosaurus displays a fleshy retractable frill, reminiscent of those of australian frilled lizards, but it is unlikely that Sarcosaurus would have these, as it would imply the presence of a complex system of muscles and hyoid bones to support it, which would be way too specific and unique for a dinosaur, so improbable, overall, for this animal. A frill-like structure could, however, be speculatively present if made by other structures, such as feathers, which require less skeletal and muscular changes to be able to work. The movie Dilophosaurus is depicted covered in a naked or scaly skin, however, the idea that feathers were a basal trait in dinosaurs is well regarded, and so basal neotheropods, such as Sarcosaurus, could have had an extensive covering of feathers, however, like many basal dinosaurs too, it would be probably that extensive patches of scaly skin would be present too, segregated from a feathered skin across the body. The Dilophosaurus in the movie is shown spitting a sort of venomous goo that is designed to blind prey, similar to a spitting cobra. However, there is no inquivocal evidence that dinosaurs were ever capable of producing venom, and such capacity may imply the presence of specialized grooves in their teeth, ot chambers in their jaws for releasing venom. However, the way the spit is administered in the movies, it appears to be used mostly to disorient prey or threats, which could be compared to the gooey vomit of fulmar chicks, that is used for defense, a far more achievable approach that could be adopted by a sleek and small vulnerable Sarcosaurus, although this would be entirely speculative.

The movie Dilophosaurus is depicted as a small but agile and long-legged theropod, which is consistent with the little we do know from Sarcosaurus, which includes the presence of long back legs, and a relatively small size for a theropod, but one whose size roughly matches that of the movie counterpart.