This thesis examines the role of animal imagery in Petrarch’s 'Rerum vulgarium fragmenta' (Rvf) as a means of elucidating his poetics in conversation with his predecessors. To achieve this aim, the present study compares and contrasts Petrarch’s poetry with that of the poets quoted in Rvf 70, namely Arnaut Daniel, Guido Cavalcanti, Dante Alighieri and Cino da Pistoia. My research sheds light on the way in which Petrarch draws on and diverges from his precursors as he establishes his poetic language. The comparison between Petrarch and one or more of his predecessors poses three areas of enquiry central to my research: Petrarch’s reuse of traditional animal images, such as those in troubadour poetry; the question of allegory in the Rvf; and the language and communication strategies which characterise Petrarch’s poetic exchanges. Chapter 1 introduces a theoretical framework, based on the sources in Petrarch’s possession, which discusses and reviews the implications, in medieval culture, of the notion of animality in relation to and in the representation of human passions. Chapter 2 considers Petrarch’s potential engagement with the repertoire of animal imagery in the tradition of Occitan poetry. It examines the set of zoological images of bestiary derivation that Petrarch shares with the troubadours, specifically focusing on Petrarch’s debt to Arnaut Daniel. Chapter 3 explores the role of allegory in Petrarch’s animal imagery as compared with Dante’s poetry. Chapter 4 considers how the employment of animal images varies between the poems without apparent correspondents and those with specific recipients. The first part of the chapter is concerned with the lyrics of Guido Cavalcanti and Cino da Pistoia, while the second part analyses animal vocabulary in the Rvf and in the poetic exchanges that Petrarch left uncollected as 'estravaganti'.