In Europe, the Quaternary, a period which started around 1,8 million years ago -according to a generally accepted, although much debated, theory-, is characterized by significantly extensive glacial and mid-glacial climatologic phenomena. The study of fauna, which was directly affected by climatologic conditions, contributes to the understanding of man’s environment during the Palaeolithic period. In the Heliadic area, a great part of our information on the Quaternary comes from Palaeontology, a science which investigates life in the past. Thus, we possess essential information on the animal species (morphology, biometry) and their evolution. However, the connection of Palaeontology with Prehistory is only at its beginning, since relevant, significant analyses -with the exception of studies referring to the rocky shelters of Epirus during the Early Palaeolithic- are for the time being almost absent: those concerning man s management of the environment, methods of obtaining games, the fauna composition in the settlements, the periodic choice of animal species, the age of comestible animals, the exploitation of animals as raw materials for tool equipment, the choice of hunting spots and temporary residence. The chief game of man and carnoyores were the herbivorous animals; their presence in the encampment is related to the climatologic data of each period and to the geomorphology of each site. For example, deers are abundant in the fauna, especially that of the Upper Palaeolithic. The elk appears sporadically, while the megaceros occurs in Middle Palaeolithic strata. The mammoth and the hairy rhinocerus appear rather incidentally (e.g. Drama’s basin), as well as in a quite south latitude (e.g. Megalopolis basin). The wild goat is an animal of the inaccessible, rocky regions (e.g. Epirus, Franchthi in Peloponnese), while the horse requires flat plains (Drama’s basin in Thessaly). The carnovores (bears, wolves, foxes, lions, hyaenae of the caves, panthers, wild cats, lynx, etc) either were hunted by men or killed by their game, a well known picture of the cave fauna. In this article, on the basis of the available data, we try to follow the evolution of species from the Lower to the Upper Pleistocene and to present the ecologic framework of each period, regardless of whether or not the bones were found in archaeological contexts.