The Dorset culture preceded the Inuit culture in Arctic North America. Inuit legends mention the Tuniit (singular Tuniq) or Sivullirmiut (" First Inhabitants" ), who were driven away by the Inuit. According to legend, they were " giants" , people who were taller and stronger than the Inuit, but who were easily scared off and retreated from the advancing Inuit. They were credited with a faultless understanding of their local environment (which they may have shared with the newly-arrived Inuit) but with inferior technologies. The Dorset did lack dogsleds, sophisticated boats and toggled harpoons and therefore may have adapted poorly to the newly harsh weather of the late first- and early second millennium.

Surprisingly, there appears to have been no genetic connection between the Dorset and the Thule, which indicates the complete replacement and extinction of the former. Nonetheless, the Dorset were kin to the modern Inuit, an earlier incursion into the Arctic region from a common population, and as such were closely related to their successors.

Anthropologist Diamond Jenness in 1925 received some odd artifacts from Cape Dorset, Nunavut, which seemed to derive from an ancient lifestyle unlike that of the Inuit. Jenness named the culture after the location of the find. His finds showed a consistent and distinct cultural pattern that included sophisticated and un-Inuit art that depicted, for example, uniquely large hairstyles for women and hoodless parkas with giant, tall collars on both sexes. A leading modern figure in the field of Tuniit/Dorset studies is Robert McGhee, who has written numerous books on this culture and the transition to the Thule (Inuit) tradition.

Canadian poet Al Purdy wrote a poem entitled " Lament for the Dorsets" which starts " Animal bones and some mossy tent rings... all that remains of Dorset giants, who drove the Vikings back to their longships..." This poem laments the loss of their culture and describes them and their end.

The Sadlermiut

In 1824, HMS Griper, under Captain George Francis Lyon, anchored off Cape Pembroke on Coats Island in Hudson Bay. The whalers discovered a band of Eskimos who spoke a " strange dialect" and were called Sadlermiut. (Sallirmiut in modern Inuktitut spelling, from Salliq, the Inuktitut name for the settlement of Coral Harbour, Nunavut.)

The Sadlermiut, living in near isolation on and around Southampton Island, preserved a culture distinct from the Inuit. They continued to have contact with Westerners and contracted Western diseases. By 1896, there were only 70 of them remaining. In the fall of 1902, some of them visited the Active, a whaling vessel that had stopped at Southampton Island. They caught a disease from a sick sailor, possibly typhoid or typhus. The entire community died within weeks.

In 1954 and 1955, Henry B. Collins of the Smithsonian Institution studied Eskimo house ruins in the Canadian Arctic. He determined that these ruins were characteristic of Sadlermiut culture which had once been quite extensive. He also found evidence that the Sadlermiut were the last remnants of the Dorset culture. Recent genetic research has, moreover, confirmed the genetic connection between the Sadlermiut and the Dorset culture.