Is the 'canine surrogacy approach' (CSA) still valid for dogs and humans in market-oriented and subsistence-oriented communities in Brazil?

摘要

Based on the assumptions that human food is available for dogs and isotope diet-tissue differences are similar in dogs and humans, the canine surrogacy approach' (CSA) has been used to infer patterns of ancient populations. The goal of this study was to test the CSA in urban (Brasilia and Piracicaba) and in rural (Ubatuba and MaraA) areas. The hair C and N isotope ratios of modern dogs were compared with those of human fingernails from different regions of Brazil. Our CSA results showed a correlation between dog and human isotopes values: in rural areas N-15 of humans and dogs was not statistically different; contrarily, in urban centres, N-15 of humans was approximately 1 parts per thousand higher (p0.01) than N-15 of dogs; humans had lower C-13 values (p0.01) than dogs in Brasilia, Piracicaba and Ubatuba. In MaraA, there was not any significant difference between dogs and humans. We concluded that CSA is still valid as a first approach in modern societies. However, isotopic differences found suggest that in modern societies processed dog food is increasingly disconnecting human and dog, jeopardising the use of CSA in the future if the trend of increasing processed dog food consumption continues to occur.