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Why Do Deer Have White Tails? (Answered)

Deer are rather shy and nervous animals. Their great sense of smell and hearing help them run away fast with even the slightest hint of danger. This wild animal belonging to the Cervidae family is prey to various predators, including humans that hunt them. So, why do deer have white tails? Wouldn’t this prevent them from camouflaging and staying safe? You might be surprised to learn how deer use their white tails to their advantage.

Read on to learn more about facts around deers and their tails.

Why do deer have white tails?

When deers become scared or startled, they will run off with their tails sticking straight up in the air. Most deers have tails with white undersides that are bright and easy to see as they run away. Since they typically live in small herds, they flash their white tails as a signal to warn other deer that potential danger is nearby. This behavior is referred to as “flagging.”

The brilliant white tail also makes it easier for fawns, or baby deer, to follow their mother out of harm’s way. Fawns can even follow the white tail through dark woods as it reflects the little existing light like a flashlight in the dark. Flagging is also a signal to predators that continuous pursuit is useless since the deer are bolting at full speed.

Do all deers have white tails?

Not all individuals. While most deer species in the Cervidae family have white in their tails, there are examples of deer, such as the moose (Alces alces) that don’t. Typically moose are dark reddish-brown or black with short, stubby tails. However, rare varieties of white moose that aren’t albinos do exist.

Examples of common deer with white tails include:

  • White-tailed deer (Odocoileus virginianus): have brownish tails with white borders on top that is completely white on the underside
  • Black-tailed deer (Odocoileus hemionus): have dark brown or black tails on top that is white underneath
  • Mule deer: are a subspecies of black-tailed deer that have white tails with a black tip
  • Reindeer or caribou (Rangifer tarandus): have white rumps and tails

What deer has the whitest tail?

As their name suggests, white-tailed deer have one of the brightest, white hairs on the underside of their tail. They are the smallest deers in the North American deer family, growing around 21 to 47 inches tall and 37 to 87 inches in length. There is also a variation of the species that is all-white and not albino.

These deers are among the most nervous and shy of the deer species and use their tail for flagging when they sense danger. But, since they are also one of the popular large game animals in the U.S., it’s understandable why they need to be cautious.

white-tailed deer

Do all deer flag with their tails?

No, they don’t, especially when there are no other deer around to warn. Usually, this trait is most common among female deer who have the motherly responsibility to protect fawns and warn the herd of danger.

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Bucks, or male deer, typically have shorter tails with less white coloring, which is less ideal for flagging. Additionally, since bucks commonly travel alone, they are known to tuck their tails when they sense danger. Tail-tucking is similar to an erect tail that signals that the deer will slink away or bolt.

Do deer communicate with their tails?

Yes, they do. As previously mentioned, deers will use their tail to signal danger to others in the group. Deer will also flick their tail casually from side to side as an “all clear” sign that danger has passed so other members of the herd can come out of hiding.

Besides protection from danger, deers will also use their tails to communicate during breeding. A female deer will raise her tail to show the white underside when she is ready to breed. During buck runs, when a buck is following a female deer to mate, he will typically run with his neck extended and tail straight out behind him.

fawn whitetail

What messages do deer send with their tails?

Besides using their tails to communicate with each other, their tails are also a great indicator of the deer’s intentions. Hunters are great observers and they will commonly watch a deer’s tail to determine the animal’s next moves.

Some common signs hunters have identified with deer tail behavior include:

  • Casual wagging: when the deer wags, swishes, or twitches their tail gently from side to side, it means they are relaxed and most likely just swishing away nearby bugs.
  • Raised at half-mast: this is one of the first signs the deer senses something is wrong and are now on alert.
  • Fast flicking: if the deer’s tail is flicking fast, abrupt, and in a jerky sequence, it means they have sensed danger is near and are about to make an escape.
  • Flaring: sometimes, a deer will flare its rump hairs, so the white on their tails are more visible. This acts as a warning flash to nearby members that trouble may be near.
  • Fully erect: when a deer’s tail raises up, full-flag, showing most of their white underside, then they are about to bolt. Deers will also run with their tails fully erect.

Conclusion

The main reason deer have white tails is so they can use them as a signal to warn other herd members of nearby danger. Female deers will also use their white tails as a guide for fawns to follow them out of harm’s way. Generally, if you take time to watch a deer’s tail, you can get plenty of clues about their moods and intentions. A trick hunters often use when trying to catch this popular large game.

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