That is funny because the same thing came to my mind when the question was asked. Eskimos are feeding primarily on seal and whale. And in Iceland I saw the diet consisted primarily of fish, sheep and lots of sweets like candy and cake.
Fish only has traces of C. I cannot find any evidence of vitamin C in lamb except the brain, which they do eat (sheeps head and sheeps head cheese):
During the summer there are a lot of greens that can provide C such as sour duck weed. Mushrooms were also pretty abundant over there and provide a little vitamin C as well.