The transition from traditional high to modern low fertility is in the forefront of empirical and theoretical investigations in contemporary aboriginal demography. The challenging question therein remains why its fertility has started to decline a century or so after the rest of Canada, and why it continues to trail the latter by a considerable lag. The objective of this paper is to present a history-based explanatory framework of the childbearing behaviour of Canadian aboriginal peoples, as it has evolved over time from the very first contact with Europeans to our day. Turning to existing theories for possible elucidation of these idiosyncrasies, we find that while accounting for certain aspects, they leave others unexplained. History provides a more satisfying explanation when we cast an eye not on the “abstract” population, “ideal-type” or what we today like to call “model”, but on real population, or family thereof, in its spatio-temporal context. The “between-two-cultures” paradigm presented here, based on ethnocentricity and dependency, could be seen as a an explanatory paradigm of competing forces on the Canadian aboriginals: on the one hand, those pushing toward modern norms of childbearing; and on the other, traditional values and structures, as shattered as they are, with their pro-natalist ideologies resisting normative changes.