Recent theories in cognitive science have begun to focus on the active role of organisms in shaping their own environment, and the role of these environmental resources for cognition. Approaches such as situated, embedded, ecological, distributed and particularly extended cognition look beyond "what is inside your head' to the old Gibsonian question of "what your head is inside of' and with which it forms a wider whole—its internal and external cognitive niche. Since these views have been treated as a radical departure from the received view of cognition, their proponents have looked for support to similar extended views within (the philosophy of) biology, most notably the theory of niche construction. This paper argues that there is an even closer and more fruitful parallel with developmental systems theory and developmental niche construction. These ask not "what is inside the genes you inherited', but "what the inherited genes are inside of' and with which they form a wider whole—their internal and external ontogenetic niche, understood as the set of epigenetic, social, ecological, epistemic and symbolic legacies inherited by the organism as necessary developmental resources. To the cognizing agent, the epistemic niche presents itself not just as a partially self-engineered selective niche, as the niche construction paradigm will have it, but even more so as a partially self-engineered ontogenetic niche, a problem-solving resource and scaffold for individual development and learning. This move should be beneficial for coming to grips with our own (including cognitive) nature: what is most distinctive about humans is their developmentally plastic brains immersed into a well-engineered, cumulatively constructed cognitive–developmental niche.