I recorded a lot of the sound fx myself, with a field recorder: tromping around in the mud at 2am ( it's too noisy during the day!! ), lodging a mic with a windscreen down in the rocks by the water; having to edit helicopters, airplanes & speedboats out, to get useable material.
Funny: I had a family of raccoons move into my attic at one point. Since I had sound fx library material, I put some snarling lion, tiger, hyena, alligator roaring sounds etc on a loop and cranked a pair of PA speakers up towards the ceiling!! It was crazy loud!!
Haha they were gone a day or two later!!
Edit- oh, and that's why you hear a terrified raccoon somewhere, in the soundtrack