Investigating Intraspecific Attacks in Brown Bears (Ursus arctos) Using a Forensic Approach: Evidence from Northern...

Area of Science:

• Wildlife Biology
• Forensic Science
• Ecology

Background:

• Fatal intraspecific aggression in brown bears (Ursus arctos) is poorly documented.
• Understanding bear aggression is vital for species management, physiology studies, and wildlife forensics.
• Forensic science aids in determining natural or illegal causes of death in wildlife.

Purpose of the Study:

• To document and analyze cases of lethal intraspecific aggression in brown bears.
• To investigate methods for identifying the aggressor in fatal bear-on-bear attacks.
• To explore the ecological and behavioral factors contributing to bear aggression.

Main Methods:

• Conducted comprehensive autopsies on four brown bear fatalities in the Italian Alps.
• Utilized forensic odontology, measuring inter-canine distance (I-CD) to estimate aggressor characteristics.
• Performed genetic analysis on saliva samples from around lesions.
• Analyzed gastric contents to understand feeding behaviors.

Main Results:

• Four cases of lethal aggression were confirmed: two yearlings and two adults.
• Autopsies revealed claw lacerations and bite marks consistent with aggressive encounters.
• I-CD analysis provided insights into the species, sex, and age group of potential aggressors.
• Genetic analysis identified the victims but not the aggressors.
• Gastric content analysis in adults suggested trophic competition, influenced by anthropogenic food sources.

Conclusions:

• Integrated forensic approaches are valuable for wildlife investigations.
• Anthropogenic food sources may exacerbate intraspecific conflict and aggression in brown bears.
• Findings offer new insights into the ecophysiology driving lethal aggression in Ursus arctos.