The Greek philosopher Protagoras, in the opening words of his lost book 'Truth,' famously asserted, 'Man is the measure of all things.' This contention-that humanity cannot know the world except by means of human aptitudes and abilities-has endured through the centuries in the work of diverse writers. In this bold and creative new investigation into the philosophical and intellectual parameters of the question of the animal, Tom Tyler explores a curious fact: in arguing or assuming that knowledge is characteristically human, thinkers have time and again employed animals as examples, metaphors, and fables. From Heidegger's lizard and Popper's bees to Saussure's ox and Freud's wolves, Tyler points out, 'we find a multitude of brutes and beasts crowding into the texts to which they are supposedly unwelcome.'