Turtles work i suppose, but i think turtles are slow and methodical, which doesn't quite fit... Turtles seem to fit ISTJ's better than INTP's.
IMO owls match better than turtles.
Ravens seem to work better, they are extremely intelligent, very adaptable, not especially social, have a slightly negative connotation, and are creators.
deus pascit corvos
(I also don't think it is a coincidence that there are 4 Raven smileys)
A couple more candidates:
Independent, Rare, Intelligent, predatory, quiet, contained, (and they are devastatingly beautiful)
aside from Lions, i think Cats in general seem to fit rather well.
Arctic Foxes (or other foxes)
Independent, adaptable, wary, insulated, sly. However whether or not we want to call INTP's "sly" is debatable, because of our general abhorrence of lies, but still, i think it pertains.
(I seem to be having a thing for snow today lol)
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