Remember that animals grow a lot faster than humans do, the baby rex in The lost world was said to be probably only a couple of weeks old, and yet look how big it was already! Remember it came from an egg so must have been egg sized a short time ago!
And remember in JP Muldoon said in response to Alan’s question on growth rate that they are “Lethal at 8 months, and I DO mean lethal!”.
So yeah I think its very likely that the rex could have grown to that size in just four years!
Also remember that Ingen probably only created a couple of rex before releasing them into the wild, so there couldn’t be too many on the island. Id say the two adults and the baby!
Some of the promo material for Fallen Kingdom stated that there were (at one time) a total of 9 Tyrannosaur’s in the wild on Sorna. However the introduction of the Spinosaurus into the wild caused an extinction event on the island.
The comparatively small size of Sorna, combined with the Spino’s hunting territory (which was large), with other top predators also on the island all were factors which caused the Spino to essentially “remove” the competition. After it had destroyed the Rex population on Sorna, it began hunting everything else.
It ended up dying of natural causes, and its skeleton was retrieved and used as a park decoration in the original JW.
Could be that the extinction would have happened even without the Spino’s introduction. I think about all the large predators already present, and as you say on a relatively small island, doesn’t seem like it would be sustainable one way or the other.
It wasn’t meant to be sustainable. Sorna was ingen’s “Factory Floor”, whereas Nublar was the “Showroom”. After JP2, the DX virus was rampant, especially in the local Compys, who were carriers of this disease. By the time of JP3, it’s thought that possibly half of the island’s herbivores either had contracted or died from DX. A few of the other Rexes died from it as well.
So combined with a plague, food shortage, and the recent eruption of Sibo, which probably dumped a LOT of ashfall on Sorna, and it’s most likely a wasteland by now. I believe that they are looking at trying to return to Sorna in the next film, tentatively titled JW Extinction. They’re also trying to find a way to have a Rex vs. Spino rematch somehow.
On a side note did anyone find it strange that in Lost World they could see all the Dinos and their locations via satellite before going to the island, but in Fallen Kingdom the dudes in the beginning went into the lagoon assuming the Mosie was dead lol?