no, grady had fresh eyes. she had been staring at it for months. have you ever worked on a puzzle relentlessly and been stuck, and then take a break for a couple days or whatever and you come back and see things that are right infront of your face that you didn't see before. i think thats what it was.

You know, that's a really good point. I didn't think of that. However, the graboids have been causing trouble for awhile and I'm sure that a scientist such as herself would have been interested in the creatures and knowing of their existence would have prompted her to look at a few pictures every now and then while she still had the unknown fossil. That's just what I figure. Grady would have known what it was right from the start as you said, but also because he was interested in the graboids and Earl. I thank you for your opinion.
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In her defense, Kate hadn't really seen graboids up close like Grady had. Come to think of it, I doubt she ever actually saw them alive at all (she spent the whole movie at the refinery). But Grady had not only been killing them with Earl, he had one burst out of the ground six feet from him just a few days before (The dragging the truck scene). It all really boils down that Kate wasn't too familiar with graboid anatomy and Grady was.