This research proposes a genealogical investigation of a model of animal government that we define “ethological”. The contours of such model emerged between the second half of the 18th century and the first half of the 19th century; its patterns show to be in tangible discontinuity with respect to those of previous models of exploitation of animal resources, as well as with those of later zootechnical and industrial models. Our thesis is that the appearance, in 1854, of a science to which the name of “ethology” is assigned, ratifies an interest in animal habits and instincts that was mainly of governmental rather than scientific kind. To develop our argument, we have surveyed a series of different discourses, in particular veterinary, naturalistic and zoophile ones. Our aim has been to discuss how the redefinition of the problem of animal government in terms of care, adoucissement des moeurs (of humans and animals) and domestication, has aroused a positive interest in animal behavior as the target of a power that is at the same time more lasting and softer, more pervasive, and less brutal. It is from this field of transformation and valorization of animal instincts that proceeds the positivity of a knowledge of animal behavior, which results to be radically different from the classical debate on the “soul of beasts”. Therefore, our line of inquiry gives us the opportunity not only to trace an epistemological history of ethology in the 19th century (which still remains a field little explored by historians of science), but also a political history of animal government. Moving past speculative and theoretical debates on the political nature of the animal question, we propose to consider instead the historical politicization of discourses and practices concerning animal exploitation. Such politicization would coincide with the turning point in the logic of power that Michel Foucault called biopolitics. We will therefore follow the stages of the epistemological and political investment in the technologies of animal husbandry, as well as the way in which this attention to the animal body (to its productive and reproductive capacities, and finally to its behavioral performances), has in turn transformed the logic of power over man considered “as a living being”. A genealogy of the rationality of animal government is in this sense an obligatory step towards a deeper understanding of political modernity in its relationship with nature, inside and outside the human being.