Abstract This study describes the use of hair traps as a complementary method to obtain samples for stable isotope analysis from medium- and large-sized mammals. We sampled three protected areas within the Atlantic Forest, Brazil. Traps formed an enclosure of ~16 m² composed of two barbed-wire strands at different heights, baited with corn, salt, fruits and cinnamon powder. Samples were identified using hair microstructure. We identified 11 species – four globally and six nationally threatened – of which 63.6% were frugivorous. We found high species richness with a small sampling effort, indicating that hair traps can prove useful for isotopic ecology and other applied ecological studies.