The purpose of this study has been to explore young children's understandings and experiences of friendship as these manifested in children's behaviours, in a reception class setting. Drawing on an evolutionary, ecological framework, friendship is seen as not only the expression and further development of social understandings and cognitive advances; more than that, making and maintaining friends is seen as an evolutionary trait and a "drive" to relate to similarly minded others. Through "niche picking", children select the environments and opportunities that suit them in order to develop their dispositions and individual traits. The research employed a participatory design in order to capture the children's views and experiences. It took place in a reception class setting, where children's everyday experiences were observed and discussed with them. The study identified six themes of analysis and offered some suggestions about creating enabling educational environments that allow the "space" for niche construction.