But it wasn't just the Distortus Rex who's been living comfortably in this ecosystem for 17 years, the Mutadon have as well!
And on top of that, when in the same area as the Distortus Rex, the Mutadon doesn't act afraid and run away, like the Dilo did when the T-Rex woke up.
Please, if you will... see my vision: The Mutadon and Distortus developing a symbiotic relationship like the Mosa and Spino, like Wolves and Ravens.
The Mutas are small (In comparison) and agile and dart around, but can't easily take down huge prey, or break through the thick hide of a deceased Anky, so they make a racket and draw the Distortus there, and also get their meal. They can go into small spaces like abandoned buildings and flush out small prey the Distortus couldn't reach. The Distortus doesn't have to waste energy trying to find food, nor get into a bunch of fights, because she has food scouts for her, and the Mutas have protection of a bigger predator, and a way to get better food than doing risky raptor ambushes all the time.
The Mutadons aren't afraid of the Distortus Rex, because they're friends!!!
...And also please imagine the Mutadon occasionally being silly and pulling on the Distortus' tail THANK YOU GOOD NIGHT