Dogs that Ate Plants: Changes in the Canine Diet During the Late Bronze Age and the First Iron Age in the Northeast Iberian Peninsula

We studied 36 dogs (Canis familiaris) from the Can Roqueta site in the Catalan pre-littoral depression (Barcelona), dated between the Late Bronze Age and the First Iron Age (1300 and 550 cal BC). We used a sample of 27 specimens to analyse the evolution of the dogs’ diet based on the carbon δ13C and nitrogen δ15N isotope composition. The results show a marked human influence in that these natural carnivores display a highly plant-based diet. The offset between canids and herbivorous ungulates does not reach the minimum established for a trophic level, which implies an input of C3 and C4 (millet) cultivated plants. Moreover, the homogeneity in the values indicates that humans prepared their dogs’ food.