Having had two Airedales through my childhood I'd be tempted to agree that their skulls can be on the formidable end of the spectrum. The second of said dogs was called Alice and upon her death it was discovered that she was nearly stone deaf from a congenital birth defect which explained the dogs trying life perfectly. I remember one perfect incident where the dog was standing next to the dining table -- no ordinary table this, you could seat 12 at it without all the leaves in it and was solid oak. Well someone called Alice and she does the usual swing the head radar trick -- except that the table leg in the way. CLUNK, my God, everybody in ear shot winced. Alice hardly even noticed. We always thought she was slow but of course if she was deaf she must've been one of the brightest dogs in creation to have managed to behave as well as she did with one crucial sense (to a dog anyway) severely impaired. The radar bit was because she only got the barest aural cue and had to scan visually to locate the source.
One of the funniest things that happened to the dog (which doesn't involve a physically solid skull so much as mentally solid one) was a during lunch one day and it was begging for a scrap of food, something we generally frowned upon. As we were building the house at the time there lots of scraps of pine lining boards lying around the place and Roger had put a 4" x 1/2" one in his pocket. Now Alice and food are a lightening combination to put it mildly and Roger gives Alice the wood instead of a piece of food. Well, SWOOOOP down goes the wood and the offended look Alice gave Roger was just pure betrayed innocence. Every since that day Alice first smelt _anything_ that was handed to her showing of course that the dog wasn't slow in the head at all, one trial learning and all.
-jonathan (j.c.f.)