Final answer:
Fixation warning behavior is measured through direct observation and recording of an animal's response to perceived threats in controlled tests, noting changes in stance, vocalizations, and vigilance.
Step-by-step explanation:
Fixation warning behavior is typically measured through direct observation of an animal's response in a controlled setting. This type of behavior is an indicator of an animal's reaction to a perceived threat and is characterized by specific physical or vocal actions that signal arousal or alertness to others. To measure this behavior, researchers will use various tests and carefully note the outcome, focusing on how the animal's behavior visually appears or changes in the presence of stimuli that could represent a threat. Examples of such behavior could include stance changes, vocalizations, or increased vigilance. The observations are then recorded and analyzed to determine the significance and intensity of the fixation warning behavior exhibited.