Complex sentence: The Skagits lived in settlements, culling their needs from the waterways and traveling by way of canoe and formed a loose confederation of tribes that only united if threatened by outside tribes such as the Haidas, who lived to the north.
Split into simpler sentences: The Skagits lived in settlements, culling their needs from the waterways and traveling by way of canoe. Skagits formed a loose confederation of tribes that united if threatened by outside tribes such as the Haidas, who lived to the north.