Fig. A.1.

Social subordination versus depression behavior in adult female cynomolgus monkeys: A) Depressed behavior includes a slumped body posture, head dropped below shoulder level, eyes open to distinguish the behavior from sleep, and a lack of orienting and responding to environmental stimuli to which other monkeys attend, in this case the photographer. B) Normal Alert behavior includes visual attention to environmental stimuli such as the photographer. C) Submissive behavior is characterized by the head drawn back, ears back, body small, and vigilance. D) This socially dominant female is displaying the aggressive behavior termed an “open-mouth threat”, her head is forward, ears are forward, and she is directly staring at the individual she is threatening.