Apennine brown bears have been living alongside humans in central Italy since at least the era of the Roman Empire. This prolonged proximity to people seems to have affected the isolated creatures’ genes, causing the animals to become less aggressive than other brown bears, according to a study published December 15 in the journal Molecular Biology and Evolution. The findings are one of the latest examples of how humans can affect wild critters—such as garbage-eating urban raccoons developing shorter snouts and feeder-visiting hummingbirds evolving longer and larger beaks.

Known as Apennine or Marsican brown bears (Ursus arctos marsicanus), the shaggy creatures have lived in Italy’s Apennine Mountains for generations. Previous research suggests the subspecies diverged from other European brown bears between 2,000 and 3,000 years ago and has remained completely isolated for at least the past 1,500 years, largely due to the spread of agriculture and increasing human density in the region. Today, about 50 individuals are estimated to remain in the wild.