Living close to humans doesn’t just change landscapes—it can also change animals themselves.
A new genetic study shows that brown bears living near villages in central Italy have evolved to become smaller and less aggressive over time.
The findings suggest that centuries of human presence have quietly reshaped both the bodies and behavior of these rare bears.
The study focuses on the Apennine brown bear, a unique group found only in central Italy.
These bears have lived alongside people for thousands of years, much longer than most other brown bear populations in Europe or North America.
Historical records and previous research suggest they split from other European brown bears around 2,000 to 3,000 years ago and have remained isolated since Roman times.
As farming expanded and forests were cleared, bear habitat shrank. Human population density increased, and bears were pushed into closer contact with villages.
According to the researchers, this long period of coexistence likely played a major role in shaping how Apennine bears evolved.
Today, these bears look and behave differently from their relatives elsewhere. They are smaller in body size, have distinctive head and facial features, and are known for being unusually calm.
Compared with other brown bears, Apennine bears are far less aggressive toward humans, which has helped them survive in a densely populated region.
To understand why, scientists used modern genetic tools to study the bears’ DNA. They created a high-quality reference genome for the Apennine brown bear and analyzed whole-genome data from several individuals. These genetic sequences were compared with bears from Slovakia and with previously studied American brown bears.
The results showed that Apennine bears have low genetic diversity and higher levels of inbreeding, which is typical for small, isolated populations. This genetic erosion increases extinction risk and is a serious concern for conservation.
But the study also uncovered something unexpected. The researchers found clear genetic signals linked to reduced aggression. This suggests that bears carrying genes for calmer behavior were more likely to survive near humans. Over generations, aggressive individuals may have been killed or removed, while less aggressive bears were able to coexist and pass on their genes.
In other words, human pressure didn’t just reduce bear numbers—it also selected for bears that were better at avoiding conflict.
The findings carry an important message for conservation. While human activities often threaten wildlife, they can also drive evolutionary changes that help animals survive alongside people. For the Apennine brown bear, this gentler behavior may be one of its most valuable traits.
The researchers caution that conservation efforts should respect this unique genetic legacy. Introducing bears from other regions could dilute the traits that have helped these bears coexist with humans.
Protecting what remains of this population means not only saving the bears, but also preserving the remarkable evolutionary story written in their genes.
