The deer tail, a relatively small appendage, is often the last thing a person sees as the animal flees a disturbed area. While seemingly minor, the tail is an important anatomical feature that varies significantly across cervid species. It is a highly visible structure used for communication and is a key indicator of the animal’s species and current disposition.
General Structure and Appearance
A deer tail, or scut, is a continuation of the vertebral column but is generally short and inconspicuous when the animal is calm. It is covered in thick, coarse hair that matches the animal’s seasonal coat color. The dorsal, or top, surface is typically darker brown or reddish-brown.
The ventral, or underside, is frequently covered in bright white hair, which is usually concealed when the tail hangs down. The tail possesses a muscular base that allows for rapid and forceful movement. This muscular control permits the deer to lift, drop, or swish the tail quickly and deliberately, setting the stage for visual communication.
Key Differences Between Common Deer Species
The appearance of the tail is the clearest way to distinguish between the two most common North American species. The White-tailed Deer is named for its broad, bushy tail, which is relatively long and brown on the outside. When resting, the tail is held down, concealing the dense, bright white hair covering its entire underside.
This “flag” of white hair can be up to a foot long and is a defining characteristic. In contrast, the Mule Deer possesses a much narrower, rope-like tail that is shorter and less bushy. This tail is white for most of its length, but it terminates in a distinct tuft of black hair.
The Mule Deer’s white tail contrasts sharply with the large, white rump patch. Larger cervids, such as Elk and Moose, possess tails that are much smaller in proportion to their bodies, often appearing vestigial or barely visible.
How Deer Use Their Tails for Communication
The tail is employed dynamically as a visual signaling device, most notably through the behavior known as “flagging.” When a deer senses danger or is startled into flight, it rapidly raises its tail to a vertical position. This action instantly exposes the bright white underside, creating a highly visible signal.
This flashing white flag serves as an alarm, warning nearby individuals that a threat has been detected. Does also use this conspicuous signal to help fawns follow them through dense brush during an escape. The tail’s movement also plays a role in chemical communication, as the swishing action can help disperse scents from glands located near the base of the tail. A tail that is held low and swishing gently often indicates that the deer is relaxed and at ease.