In the video Two-and-a-half billion T. rex roamed Earth, study finds contains a short explanation of the results in Science Absolute abundance and preservation rate of Tyrannosaurus rex by the corresponding author of the paper.

I'd like to understand better what is known about T. rex's adaptability and range of environments where it was thought to flourish. It's hard to imagine what things were like back then, so using modern flora/fauna and climate distributions as reference points will help me to understand this better.

Based on that knowledge and reference frame, I'd like to ask about the following Gedankenexperiment:

Question: Would anything limit an "invasive species" T. rex introduction now besides running out of food or intervention by humans?

Would they basically thrive over much of the Earth's surface and eat all the other mammals? Or without a supply of dead and rotting dinosaur cadavers would these giant scavengers with excellent olfaction quickly deplete a small region and die of starvation?

Currently there is not likely enough DNA to reconstruct a full genome nor a scheme to build and incubate a dinosaur egg for it (as far as I know), so we are not at any risk of this happening in the near future.

  • 4
    $\begingroup$ Fun question, there are too many ecology variables to give a definitive answer, perhaps T-rex was an ambush specialist... folks on a paleontology forum would know. If the oxygen levels were OK and there were many buffalo, hippos, rhinos and elephants, i'm pretty sure T-Rex would be unstoppable! $\endgroup$ Apr 19, 2021 at 8:36
  • 1
    $\begingroup$ It seems that if the current earth could support terrestrial predators/scavengers the size of T.rex, there would be one already. Terror birds were around relatively recently (2 million years ago) but instead of getting larger, they went extinct $\endgroup$
    – timeskull
    Apr 19, 2021 at 19:27
  • $\begingroup$ @timeskull I'd always thought that population dynamics was more complicated than that, and that there could be multiple equilibrium points or alternative stable states especially when there's been a significant change in the status of a keystone predator. $\endgroup$
    – uhoh
    Apr 19, 2021 at 21:57
  • $\begingroup$ @aliential I've added a bounty. $\endgroup$
    – uhoh
    Apr 23, 2021 at 22:12
  • 1
    $\begingroup$ @aliential Who needs buffalos there are billions of easy livestock humans have confined with fences and pens a rex can step/reach over. Also remember there is decent evidence T-rex are pack hunters. $\endgroup$
    – John
    Apr 25, 2021 at 1:38

1 Answer 1


Lots of things could impact a reintroduced invasive species.

  1. Disease/sickness: although no close relatives are present that is not a guarantee, many diseases jump species. Parasites likewise could cause problems, especially newer parasites the dino may not have a good defense for. Even modern Fungus could pose a problem for eggs.

  2. Predators: While an adult t-rex is predator proof eggs and newborns are not. Rats and other small mammals as well as many birds have been the demise of many ground nesting birds.

  3. Poisons: there are plenty of animals and plants that are poisonous enough kill a t-rex that the rex may not recognize as dangerous. Remember there are a lot of things around a t-rex did not evolve with. This is more dependent on location, a t-rex dropped in Australia might kill itself with its first meal.

  4. Human stuff: I am not talking about humans killing them. I am thinking of the things humans make killing them. things like walking into power lines, eating weird plastic human garbage, car accidents ( a car moving at speed could easily cripple a rex), even something as simple as getting hit by trains


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .