Caribou are simply unlicensed reindeer. Which is stating the same thing but from the opposite perspective. Reindeer are caribou which are a couple of generations removed from the original caribou which were native to Alaska. The "originals" were dying out of their own accord in the last century and a small herd was imported from Scandinavia and turned over to natives who had no history of herding anything but who made it work though they stayed with dogs to pull the sleds rather than harnessing up the reindeer as, particularly, native Finnish peoples did. No, reindeer don't have license plates; they have ear tags. Caribou do not.
Yes, they do mate under the elevated sections of the Trans-Alaska Pipeline. Yes, I have seen them do it though they weren't too pleased with being watched. Maybe that's why there are no caribou porn films to delight you libbies.
A favourite place to visit, briefly, is the village of Anaktuvuk Pass.
In fairness, I haven't been there in many years; last back around the time I took the photos (for AP) of the friggin' California idiot who set out to row a bathtub to Russia (which he could easily see from Alaska). See the "Black & White" thread if you want to gawk.
Now, a few things ya gotta understand:
The village (Wikipedia calls it a "city") is at the foot of a mountain pass to which the approach is steep. The caribou migrated through the pass twice each year.
"Tuvuk" is the native name for caribou (used interchangeably for reindeer).
"Anak" is the native word for shit.
So the village name, translated into words you might be able to pronounce, is "Caribou Shit Pass".
That's because caribou are smarter than liberals. They understand that it's easer to aspire to heights if you shit first rather than on each other along the way.
But Governor Palin was a tad too polite to explain that.