There are wild reindeer in the eastern fjords (although I missed my one chance to take a picture of the ‘caribou next 2 miles’ sign).
This prompted a conversation in the car about the differences between caribou and reindeer (a difference in semantics really only used by North Americans, I discovered — apparently everyone else just calls them Reindeer. I was always told that they are the same animal — reindeer are (semi-)domesticated, caribou are not. It’s really the primary difference between them, and any behavioral differences are related to domestication
This is mostly true, but the differences between the two animals are beginning to skirt the edge of “not the same species’ any more. They are both Rangifer tarandus, but are considered a different sub-species. Reindeer are smaller and stouter as a result of domesticated breeding for draft animals, and they no longer make the huge migrational treks that their wild cousins do.
A possible reason to split them into two separate species, though, is that domestication brought on changes in the breeding season (reindeer are much earlier in the season than caribou), which means that there is little chance the populations will interbreed. The populations were forced apart by ice-age migrations, and the local peoples domesticated them about 2000 years ago. Since then, the groups have been slowly drifting apart.
Whether this means that they are actually separate species is another question. Recent genetic tracking is trying identify different groups within the larger species, and may show that there are distinct-enough differences to warrant putting them in different species. And maybe not just two — North American caribou have several different habitats and migration patterns that give them distinctive behaviors.
It seems a bit of a moot point, though, as fourteen subspecies of caribou/reindeer are known. Whether you call them reindeer or caribou seems to be a semantic issue.
The other thing I learned was that both male and female caribou grow antlers. Huh.