This persistence is unusual by the standards of North American prehistory.

In many parts of the continent, the resources that supported early populations changed dramatically over the post-glacial period — as the megafauna went extinct, as climate change shifted ecological communities, as sea levels transformed coastlines.

The early coastal peoples of the Northwest Coast adapted to an environment that, while it changed in detail across 10,000 years, maintained its fundamental character: a resource-rich marine coast with enormous annual salmon runs and abundant marine mammals.

The exceptional stability of the Northwest Coast environment, relative to many other parts of the continent, may be part of why the exceptional depth of cultural and genetic continuity on this coast is possible to document.