This paper is comprehended in the study of the application of the biomimicry science in building services and energy management, taking as a reference the case of tuna. Tuna generates heat in the muscles, organs and tissues of the inner area of its body (dark muscles). This heat is distributed in the periphery in order to maintain constant body temperature. From this biological reality, researchers analyse the possibility of altering the heating demand of an office on the basis of the heat conservation strategy applied by tuna, merely modifying the working-spaces. For this purpose, an existing office building with high architectonical quality parameters has been chosen and different scenarios have been defined in order to perform the energy simulations. The case studies correspond to the variations in the floor layout and occupancy density distribution. Besides, they are studied in three European cities with different climate. The evaluation of results is mainly focused on the heating demand since tuna strategy comprises the heat management. It is shown that the arrangement of high thermal load locals affects the heating demand of the building, being more efficient the tuna distribution in order to lower the demand.