That thing which sets one of my dogs apart from the others in terms of tendencies, desires, whatnot, that is not akin to cosmetics (i.e., appearances).
Intelligence
Problem solving abilities. None of my dogs has gotten past the "nose the already open door open to get into the house" (and one of them can't even figure this one out). Hell, even the cats have figured out what doorknobs are for.
Design
Now, now. This is something that y'all have yet to define, though you claim to see it everywhere. I'd definitely look for a maker's mark or serial number (or "patent pending" stamp). One of my dogs has spots, but they're rather random and amorphous, so I don't think they'd count.
Learning experiments usually exploit natural tendencies in animals. Cats are excellent escape artists.
I have a hammer that has neither of the above. Should I assume, therefore, that it has no design or purpose?