Some reasonable explanations for why “dinosaurs” would be able to survive on Isla Nublar/Sorna, but not worldwide.

Can you think of any other in-universe explanations based in science?

Remember: Although genetically engineered, “dinosaur” biology is largely optimized for the ecosystem and environment of their time — not ours.

• They already struggle with the reduced oxygen concentration in the atmosphere, which makes it difficult for them to breathe at elevation with decreasing oxygen concentration and pressure.

• They are not well-adjusted to seasonal changes or fluctuations in day length — they interfere with their circadian rhythms, migrations, and breeding.

• They are unable to achieve replacement numbers and establish sustainable breeding populations.

• They are unable to obtain the full range of nutrients that they require from a natural diet due to modern gut flora and therefore suffer from vitamin or mineral deficiencies.

• Their nests and eggs are routinely destroyed by opportunistic mammals and birds.

• They are vulnerable to the modern pathogens that spread through animal populations, the likes of which are plentiful on the mainland, but are not as common on an isolated island.

• They are actively hunted or poached or otherwise destroyed as pest animals.