How do scent marks help mammals defend territories?

Scent marking is a vital form of communication used by many mammals to advertise and defend their territories. By depositing complex chemical secretions from specialized glands—such as preorbital or pedal glands—or through urine and feces, animals create persistent markers at territorial boundaries.1

These scent marks function as a sophisticated communication system in several ways:

• Individual Identification: Scents allow animals to distinguish their own markings from those of other species or individuals of the same species.1
• Temporal Information: Because scent secretions are complex, they change over time as volatile components evaporate. This enables recipients to judge the age of a mark, helping them determine if an intruder is recent or from the past.1
• Boundary Maintenance: By frequently refreshing these marks—such as through habitual defecation at specific sites—territorial males maintain the odor quality of their boundaries, effectively signaling their presence and ownership to others.1

While the exact mechanisms of perception remain under study, the Jacobson organ is believed to play a key role in detecting these chemical cues.1