The aim of this paper is to explore the reasons behind the differences between the organizations dealing with the animal protection and the other environmental organizations. In that sense, the focus of our analysis is the grassroots character of these organizations/associations as well as the emotional basis of the member participation/mobilization. We draw upon the data gathered through the interviews with the organizations' representatives as well as through the analysis of other sources of information such as websites, internet presentations and annual reports of animal protection organizations. For the comparative purposes, we use a part of the material gathered in the semi-structured interviews with the representatives of the fifty Serbian environmental organizations.