This article investigates the redefinition of human and animal sociabilities in the light of comparative anatomy. Linnaeus's classification questioned and redrew the frontiers of humanity, raising new debates on what makes a being human, who or what is entitled to humanity, what corrupts humanity, and why some beings degenerate. Enlightenment anthropology, as a new science accommodating itself to philosophical inquiry, became an ideological battleground on which two representations of man's degeneracy were fought out. Was human depravity the consequences of consumption, luxury, and social needs that increasingly characterised European cultures in the eighteenth century, or was it to be understood as a result of physical degeneration, that is, alienation from the civilised world? The natural man, whether as an imaginary state or embodied in ‘wild' creatures, crystallised the anxiety about degeneration and natural forces acting upon bodies and organisms. To ring-fence humanity and distinguish it from the lower orders of nature, typically human attributes were constructed in comparative anatomy discourses. Reason, language and sociality came to characterise human behaviours while animals were deprived of any ‘social’ faculties. Through analogy, the human social group was often compared to insect communities or animal herds, clusters or shoals, yet these animal or insect assemblages were systematically studied from an anthropocentric perspective. The article weaves seemingly disparate discourses - the writings of the Comte de Buffon, Jean-Jacques Rousseau, Lord Monboddo, Johann Friedrich Blumenbach, William Lawrence and Samuel Taylor Coleridge - into a dialogue and debate that decisively defined the nature of human and animal sociabilities.