Yep, I'm also with Malte here about the degeneration of sharpteeth as the sequels went on. How did that guy get stuck between some rocks, anyway?
Same with 11, the bit of threatening atmosphere the two raptors brought completely vanished when the tiny longnecks started tickling them. The ones from 13 weren't tickled but there were driven off a cliff by yellowbelly "singing". It was ridiculous. I loved the predators from the early sequels, let alone the one and only Sharptooth himself. The later ones didn't live up to that standard at all.
About the ticklish part... It might not be too different to us. Some of us are ticklish, others not so much. I imagine it might not be too much of a different story with sharpteeth, or dinosaurs in general. Well, in the LBT universe, at least. :unsure: