Tech UPTechnologyHow did Jurassic park's 'Triceratops' get poisoned?

How did Jurassic park's 'Triceratops' get poisoned?

In the 1993 film Jurassic Park there is a scene that is hard to forget.
As the experts return to the visitor center after their failed visit attempt, Dr. Malcolm tries to explain to Dr. Sattler a simplification of chaos theory. Dr. Grant, not paying attention to the conversation, hears a noise outside and jumps out of the moving car. Malcolm jokes about it, but Sattler follows the scientist, heading into the jungle. The cars stop, and the entire troupe joins the two paleontologists.

Arriving at the source of the noise, among the tall grass, they discover a huge Triceratops lying down. It doesn’t move, just breathes heavily, kicking up little clouds of dust with each exhalation. Mr. Harding, her caretaker, explains that she is ill, that Robert Muldoon administered a tranquilizer, and recounts the symptoms, while she examines her tongue and pupils. He explains that it happens to him every six weeks, more or less.

She notices that the animal has dilated pupils, something that does not fit with the effect of the tranquilizer, and deduces that it must be a pharmacological effect of the surrounding plants. Then, paleobotany discovers a plant that may be the cause.

Lilacs from Persia, or from Florida?

Although in the Spanish dub Ellie says that the plants are lilacs from Persia, in the original English she speaks of the West Indian lilac. But they are two different plants.

The Persian lilac is a shrub of the Oleaceae family, with the scientific name Syringa × persica , a hybrid variety used in gardening. On the other hand, the plant that in English is called West Indian lilac bears the scientific name

Tetrazygia bicolor, a natural species from Florida, of the Melastomataceae family, for which we do not have a common name in Spanish, although by translation we can call it “Lilacs of the West Indies”. This species indeed corresponds to the plants that Ellie Sattler observes.

The toxicity of this plant is not real , it is part of film fiction. In fact, birds transport and disperse their seeds through their digestive tract without any problem. However, we must bear in mind that the Melastomataceae family began to diversify during the Cenzoic, after the extinction of Triceratops 66 million years ago. Therefore, there could be some substance in the plant that is not toxic for a modern animal, but it is for our protagonist. We can therefore assume the film fiction and accept that, for the Triceratops , the fruits of lilacs from the West Indies were toxic.

The fact is that Dr. Sattler checks the excrement of the dinosaur, and finds no remains of fruits or seeds. The story progresses, the argument continues, time passes, the film ends with an epic ending, and nothing more is known about the Triceratops or the cause of its intoxication.

the lost scene

But back to the movie. While the rest of the visitors return to the cars, Dr. Sattler decides to stay with the Triceratops. However, if we look at the original script of the film, in that scene -scene 44- a conversation between Tim, Alan and Ellie is missing, in which paleontologists speculate that, as a good herbivore, if the Triceratops ate lilac fruits, so abundant in the area, she should be sick all the time and not just once every six weeks.
Meanwhile, Tim fiddles with a smooth round stone he has found and interrupts the scientists’ conversation, saying that he has seen those stones in Grant’s picture book.

Then Dr. Sattler looks at the stone and solves it. Gastroliths!
The Triceratops is not constantly sick because it does not eat fruits constantly. Lilacs are not part of its usual food, but are consumed accidentally when swallowing gizzard stones.

the gastroliths

Some animals that lack teeth have food that is hard and difficult to digest. To aid in digestion, they ingest stones that they lodge in their stomach or gizzard , a very muscular organ of their digestive system. When the food arrives, the muscles forcefully pump the contents, causing the stones to collide with each other and with the food, grinding it up.

We find gastroliths in many modern animals such as some cetaceans, seals, crocodiles and, of course, in birds, especially herbivores. Regarding dinosaurs, gastroliths have been found in a good number of herbivore fossils.

When the gastroliths are already too used and do not fulfill their function, they regurgitate them and swallow new stones to replace them. In the movie, Triceratops replenishes its gastroliths every six weeks or so. And when he does, he accidentally eats lilac berries too. For this reason, she only gets sick every six weeks, and there are no traces in her stool.

This deleted scene that explains the intoxication we find practically the same in Michael Crichton’s novel . Although in the latter the sick animal is not a Triceratops but a Stegosaurus , which gives the chapter its name.


Koepp, D. 1992. Jurassic Park screenplay .
Renner, SS et al. 2001. Historical biogeography of Melastomataceae: the roles of Tertiary migration and long-distance dispersal. American Journal of Botany, 88(7) , 1290-1300. DOI: 10.2307/3558340
Wings, O. 2007. A review of gastrolith function with implications for fossil vertebrates and a revised classification. Acta Paleontologica Polonica, 52(1) , 1-16.

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