"How would it know to do that?"

(Jurassic World spoilers)

The Indominus rex is shown to have some extraordinary abilities the humans around her seem to not have known about, and which prove quite useful for escaping and avoiding capture.

How did she realize to do all of this, and what exactly does she actually do?


Camoflaging

It's probably the most straightforward one for her to figure out how it could be useful. She notices she can change into the colour of her surroundings, and that probably means she's harder to see. Being able to hide is not an unusual thing for an animal to want.

Maybe the first time something spooked her and she did it instinctively, to a small enough extent it went unnoticed. Maybe she started practicing doing it voluntarily whenever she had enough privacy, or just was able to do it voluntarily now that she had learned she could do it - if she had no control over when to do it she would probably have been discovered to be able to do that sooner, so I presume she does, and that she understood it's something she doesn't want the humans to know about. It's them she wants to hide from, after all.

Avoiding detection by heat signature

This is a little more complicated for her to understand the full potential of. How does she know about the technology that monitors her location in the paddock by sensing her body heat? Well, she doesn't, or at least not that it's machines doing that, and assuming it's being used on her is not necessarily by observation.

Claire: They say it can sense thermal radiation. Like snakes.

It's because she can do the same thing that this technology does, so why wouldn't someone else in the world be able to do it, too. If she can still "see" herself when she's camoflaged, someone else can probably see her, too. When she wants to disappear, better do everything she can.

Removing her tracker implant

How would she know the humans are using it to track her? Maybe she doesn't, and maybe it's not even why she removed it. It kind of seems like she's laid a trap and is waiting for the ACU to come to the bait she's left for them, but like Hamada says when finding the implant, the blood on it had not clotted yet - she had only clawed it out just before they showed up. That she was still near the implant may not have been a plan at all, and she may not have had any idea what the thing she removed from under her skin was. She may not have actually even needed to remember where the humans had inserted it.

She's "bigger than expected", right? The tracker was put in while she was still growing. Maybe it just got uncomfortable as she got bigger around it, enough so that she wanted it out.

Why remove it now, though? Maybe now the humans weren't there to stop her. She could have been reacting to it before, without the humans realizing what the matter is exactly, and something would have been done to prevent their expensive dinosaur hurting herself. Not sure what, but I assume they have some kind of protocol at the park for how to deal with unwanted behaviors, and she got the message the humans were going to do something she didn't like if she kept scratching herself. Not picking at a source of discomfort is not something animals usually understand, or cone collars wouldn't have to exist, but she's supposed to be a weirdly smart animal, isn't she. Just not in the way that she understands how human technology works when she probably hasn't even had the opportunity to see it being used before.

Maybe she didn't stop to wait for the ACU troopers to gather around her so she could attack them, but instead they caught up to her when removing the itchy thing slowed her down, and she tried to hide and wait for them to leave. They didn't, so she shook them off another way.

Getting the humans to open the gate for her

This... probably would not have worked if the humans hadn't been so quick to jump to the worst possible conclusions and had been paying more attention.

There are construction workers all around the paddock when Claire and Masrani visit, and they're still there when Claire returns with Owen. If an animal of that size had climbed over the fence, it's pretty unlikely no one would have noticed.

The clawmarks are even on a wall that's facing the camera in the first shot of the paddock from the outside, so it's not like they're in a corner hidden in the surrounding forest. She likely made them while the paddock supervisor (whose name's apparently Nick, says the wiki) was away from his post. He leaves when Claire and Masrani arrive, and maybe took a while to return after they had left, taking that opportunity for a bit longer break. I'm glad I noticed that because this would be pretty ridiculous otherwise, but apparently the Indominus noticed no one was watching, too. The construction workers outside the paddock may have heard her scratching the wall, but no one asked them.

That the Indominus' escape plan works is because lucky for her, communication between workers and leadership of the park is limited, and the people who do think she's already escaped don't stop to think much in their panic. There's even Claire's a bit less insultingly written character flaw of not trusting others to handle things, because I bet she wished later that she'd just called the control room from the paddock before doing anything else, instead of rushing to get there personally. Not that Owen's the one here who did everything right or anything, as he doesn't bother to ask any potential eyewitnesses either, before assuming the huge dinosaur could have escaped without anyone noticing, and going inside the paddock to see things up close himself, not trusting the other two people investigating the apparent escape, whose job that is more than it's his, to notice everything important.

Did the Indominus mark up the wall to lure people into the paddock? How did she know to do that, and how did she know it would lead to actually getting out?

It's possible it actually started as an escape attempt instead of a distraction, but turns out, no, she can't climb over the wall after all. She did her best to hide from the humans right after, though, so the idea that humans thinking the paddock is empty might lead to them accidentally letting her out does seem to have occurred to her at the latest as something to use the evidence of her failed escape attempt for. It's not like she knew what's on the other side well enough to know someone should have seen her if she had actually escaped. What made her think she'd get a big enough gap opened in the fence to get out of, though?

Nick: These doors haven't been opened in weeks.

The gate has been opened during the time she's been in that paddock, even though she apparently was small enough when brought there it may not have been through that route, considering she's been there "all her life". There's no mention of the paddock perhaps having a section that can be closed off temporarily, to keep the animal from getting out when the gate has to be open for a time, so she was probably tranquilized for that, but either way she was aware enough for long enough to see that the wall can open there. Once the humans were in the same space with her, she did kind of chase them towards the gate, so it's their only escape route. If she's seen the humans operate the gate's controls, she knows they can open it, even if she can't. Or, I guess she could have just wanted to see what happens and hope she can lure in something to hunt in all her boredom, and that it led to an escape was bonus.

She did need some strategic thinking to get the ball rolling, but that it worked is caused less by her chessmaster skills and more by the humans' carelessness. On the other hand, maybe the Indominus did know the humans keeping her in a cage are prone to jumping to conclusions and have poor communication. She's spent all her life observing whoever shows up behind the glass for her to stare at as her only available entertainment, after all.