Which type of indication involves behaviors such as scratching, biting, or barking?

The type of indication characterized by behaviors such as scratching, biting, or barking is rooted in the dog's instinctual responses when they detect a certain substance. This indicates that the dog is expressing heightened excitement or agitation towards the target odor, which is often related to the presence of narcotics.

In this context, aggressive indications are linked to the canine's behavior when it perceives the presence of the scent it has been trained to detect. Such behaviors reflect an active engagement with the target, suggesting a strong alert or alertness to the presence of contraband. The dog may be driven by a sense of urgency or alertness that manifests physically in these more assertive reactions.

On the other hand, passive indications would involve less overt expressions, where a dog may sit or stay close to a location of interest without excessive movement or vocalization, indicating the presence of a substance in a calmer manner. Active indications, while somewhat similar to aggressive behaviors in that they denote a clear alert to something of interest, typically involve positive behaviors like searching or signaling rather than the more forceful actions associated with aggression. Calm indications are not related in this context, as they suggest a lack of heightened behavior regardless of the odor's presence.