Unfortunately, Dr Grant was wrong, and this theory only comes from Jurassic Park and is not accepted at all in paleontology. I will use [this article][1] , but there are a lot similar on the web that answers the same question. The T-Rex has a very developed sense of smell, so the "don't move" theory is already broken by that fact. Furthermore, he has front-facing eyes, and his binocular range was 55 degrees which is actually greater than that of a hawk. You can find other crispy details in this article if you want some more infos! [1]: http://www.iflscience.com/plants-and-animals/could-t-rex-really-only-see-you-if-you-moved