I am not sure on the regulation concerning bringing back the skull or even a whole animal so you may want to check it out to make sure before you go. Your outfitter should be able to tell you the regulations. I presume that is has something to do with the "mad cow" thing that was going on in Canada a few years ago but I am just guessing. My outfitter just boiled my bear skull enough that it was cooked, when the US Customs officer looked at it he didn't say anything about it. He didn't want to see the bear hide but may of presumed that it was taken care of properly, who knows?