What action is expected from a dog once it detects a target odor?

The expected action from a dog once it detects a target odor is to transition to a behavior indicating the presence of that odor. This behavior, often referred to as an "alert," can manifest in various forms depending on the dog's training. Common alert behaviors may include sitting, lying down, or indicating the source of the odor with their nose. This transition effectively communicates to the handler that the target substance is nearby, allowing for further investigation or action.

Other options do not align with the intended purpose of narcotics detection work. Engaging in playful behavior would distract from the task at hand and is not a trained response to successfully indicating the presence of a target odor. Remaining calm may suggest awareness but does not convey the specific detection that the handler requires. Stopping the search entirely would negate the purpose of the dog's training, as continuing to search or indicate presence is crucial for the effective detection of narcotics.