Ever since the first ethnographic studies, the question about how people learn in different contexts was an essential element of research. Studies in anthropology of education have increasingly focused on schooling. Nowadays, however, the traditional topic of learning in out-of-school contexts recovers its relevance because the development of technologies, globalisation and inequality create new contexts for knowledge. Peasant and indigenous children's productive activities in countryside are frequently defined as children's labour, tending to emphasise the obstacles to attending school and ignoring the production of knowledge about natural world. In this article, I will use concept of legitimate peripheral participation to identify situated learning outside school walls. This category allows me to describe the understanding of natural and social world that peasant and Mbya-Guarani children in rural areas of San Ignacio (Misiones, Argentina) achieve in their everyday learning experiences. Information about plants, insects, animals, birds, their customs, food preferences, reproduction methods and environment are learned by observing and doing, while science lessons usually ignore such familiarity. (Contains 3 figures and 5 notes.)