Recent research shows that a unique population of brown bears in Italy, the Ursus arctos marsicanus, has become less aggressive over generations due to prolonged contact with humans. This counterintuitive evolution stems from the bears’ isolation and subsequent inbreeding, which, surprisingly, has favored traits that reduce conflict with people.
Centuries of Isolation
The Apennine brown bear exists exclusively in central Italy and has been genetically separated from other European brown bear populations for 2,000 to 3,000 years – essentially since the Roman Empire. This isolation, combined with habitat loss from agriculture and human settlement, led to a drastic reduction in genetic diversity and increased inbreeding within the species. Despite the negative consequences of inbreeding, researchers found that it also inadvertently selected for less aggressive behavior.
Human-Induced Evolution
A study published in Molecular Biology and Evolution reveals that Apennine brown bears carry genetic markers linked to reduced aggression. The researchers from the University of Ferrara used genomic analysis to determine that humans have inadvertently shaped the evolution of these bears.
“Human-wildlife interactions are often dangerous for the survival of a species, but may also favor the evolution of traits that reduce conflict,” said geneticist Giorgio Bertorelle.
The study suggests that bears exhibiting more aggressive behavior were likely eliminated by humans, leading to the selection of genes associated with calmer temperaments. This is not necessarily a positive outcome for the species’ overall health – inbreeding still poses a threat – but it does highlight a surprising consequence of human-wildlife interactions.
Paradoxical Implications
The findings present a paradox: while human activity has endangered the Apennine brown bear, it has also inadvertently driven the evolution of traits that minimize conflict. This suggests that even severely impacted populations may retain valuable genetic adaptations that deserve preservation. The study underscores the complex relationship between humans and wildlife, demonstrating that even negative interactions can lead to unexpected evolutionary outcomes.
The Apennine brown bear’s story is a reminder that evolution doesn’t always follow a straightforward path. Sometimes, the very pressures that threaten a species can also reshape its behavior in ways that ensure its survival.
