Jurassic World: Evolution is out tomorrow and it's awesome, but when you start the game most dinosaurs will be locked. The hardest animal to unlock is the Indominus Rex, the gene-spliced monster of the Jurassic World movie that caused the park to collapse.

Hopefully you'll have more luck, as we show you how to unlock the I-Rex in Jurassic World: Evolution! It's part of the late-game content and is a real challenge to get... and even more of a challenge to keep happy. Good luck.

Jurassic World: Evolution - How To Unlock The Indominus Rex

"That thing out there... That is no dinosaur." - Owen Grady

The I-Rex is one of the hardest dinosaurs in Jurassic World: Evolution to unlock, since it can't be received from fossils at an Expedition dig site or a mission like all the other dinosaurs in the game. Instead it requires Research, and some very specific requirements. These are:

• Have 4 Research Centers - that's either one over four islands, or multiple ones per island. We wouldn't bother building more than one, since you probably won't get I-Rex until the fourth island.

• Have $2,000,000 - the cost of the research.

• Tyrannosaurus Rex Genome at 100% - this may be possible on island three, Isla Tacano, but we suspect not until island four, Isla Pena, when enough T-Rex dig sites open up.

• Velociraptor Genome at 100% - easy.

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After you have fulfilled these criteria, go to the Research page under 'Genetic Research' and the I-Rex has got a hexagon all to itself. Pay for it, and be prepared to pay just as much to incubate it - not to mention cater to its fussy demands! Just pray it doesn't get loose...