Same here. I think its got to have at least some to do with their size. I mean 1) the smaller they are the more threatened they must feel (you could eat them,) If they've made it this long they can be reasonably assured nothing is going to eat them, and B) think of little kids, they're always much more energetic and rambunctious than adults.
My older ones are not as twitchy but they all do a bit if you touch their head. I'm sure you could get then used to it a little. The adults seem much more content to just sit there.
Direction they see? I'm not sure I understand the question....
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