User blog comment:Gekkou30/The T-Rex Roar/@comment-6493791-20130815022528

I believe it was a combination of several animal noises, like the raptors had a Dolphin shriek when charging, the dilophosaurs had raddlesnakes 'rattling' when spitting, etc. The exact animals I'm not sure about, but I know the film crew went out and recorded several sounds from living animals.