This chapter explores the cultural niche dynamics of hunter-gatherer-fisher populations along the southern coast of Tierra del Fuego during the Holocene. Integrating palaeoenvironmental data, demographic reconstructions, archaeological site distributions, technological assemblages and genetic evidence, this study examines how human groups adapted to environmental variability and shifting social interactions over time. Radiocarbon-based demographic models reveal periods of significant population growth, especially between 7500 and 6300 and around 500 cal yr BP, interrupted by phases of decline, notably between 4800 and 2000 cal yr BP. Technological transitions, such as the adoption of bifacial projectile points and shifts in bone tool diversity, align with demographic and ecological changes. Spatial analysis of lithic raw material circulation—especially green obsidian—demonstrates long-distance interaction networks and fluctuating connectivity across the archipelago. The study further examines genetic data to understand inter-group relations and cultural transmission mechanisms. This work highlights how cultural niche construction in this sub-Antarctic environment was shaped by resilience strategies, technological innovations and the evolution of social networks in response to dynamic climatic and demographic pressures.