What feature is displayed by the whitetail deer when alarmed?

Answer

A flash of the bright white underside of its tail held high.

The common name of the whitetail deer, Odocoileus virginianus, is directly derived from a distinctive visual signal they emit when they perceive danger or become alarmed. When fleeing, the deer raises its tail high, exposing the bright white fur on the underside. This flash serves as a clear, unmistakable signal to other deer in the vicinity, alerting them to the presence of a potential threat or encouraging them to join the flight response. This behavior, often referred to as 'flagging,' is instantaneous and highly visible, contrasting sharply with the surrounding environment as the animal bounds away.

What feature is displayed by the whitetail deer when alarmed?
animalmammalwildlifedeerruminant