There are several myths and misconceptions about the origin of the pig’s curly tail. In this article, we are going to explore the common tales of why do pigs have curly tails?
The most common is that pigs were bred to be used as weapons in war, and tails were docked to avoid entanglement in forest brush or being grabbed by an enemy.
If this were true, then all curly-tailed pigs would have originated from a few specimens which were selectively bred for their lack of a tail, which is not the case.
Why do pigs have curly tails?
Wild male pigs often have straight tails.
Male domesticated pigs, regardless if they are wild or bred as livestock, also generally have straight tails.
Pigs with curly tails have not always had curly tails.
What is happening is that the males are fighting – they don’t use their tusks for fighting, but they bite each other.
When a male pig has a fight and wins, he will often bite the other male’s tail off so it can’t use its tail to fight back.
This makes the loser’s tail curly!
However, this is still a theory, since it’s hard to say exactly why some pigs would have naturally curly tails.
Some wild female pigs in their breeding prime may be attracted to a male with a curled tail and, over time, this trait could spread through the gene pool.
1. Are pigs born with straight tails or curly tails?
Pigs actually start out with a curly tail, and it is straight at birth.
Their tails are mostly straight until the males fight each other, and then they curl from regular use.
Domesticated pigs have their tails in a curl, where wild boars don’t, because domestication affects the tail.
So why do pigs have curly tails?

Kiley Worthington (1975) concluded that farmers use the curled tail posture of pigs as a health indicator.
However, this study is quite dated and conclusions seem to be a bit oversimplified.
It is possible that a curled tail is linked to high arousal and partly to a positive emotional state.
In conclusion, it seems that pigs are born with curly tails and, later on in life, can become straight or can remain curly.
This has not yet been scientifically proven though, so for now, we can only speculate.
2. What’s the origin of the term “curly tail”?
There are several theories why do pigs have curly tails:
•The most common theory is that pigs have curly tails because when a male pig bites another male pig’s tail, it curls.
•In some countries, pigs with straight tails are not considered to be purebred and are not allowed to breed.
Pigs with curly tails often do not have this restriction.
Thus, in these areas, the term “curly tail” may indicate a “purebred” animal.
•Pigs that have curly tails are also called “curly-tailed pigs” or “curly-tailed swine.”
•Another theory is that the term may stem from a corruption of the term “coir-tails”, which was used to describe pigs that were raised on an island off the coast of Scotland.
The island, called Colonsay, had curly-furred pigs, and when they were brought to other parts of Scotland, the “curly” was dropped and the term only used to describe swine.
3. Do all pigs have curly tails?
Not all pigs have curly tails.
Some pigs are born with straight tails, which will remain straight their whole lives.
Pigs with naturally curvy tails would need to go through a fight before the tail became curly, while pigs that were born with curly tails tend to have them from birth.
Examples of breeds with straight tails include the Berkshire, the Duroc, and the Hampshire.
4. When does a pig’s tail curl?
Aside from asking why do pigs have curly tails is “when do they develop a curly tail”? Usually, the tail begins to curl within two months of being bitten.
It can take up to 6 months for the tail to fully curl.
5. What does it mean when a pig’s tail is straight?
Straight tails in pigs mean they have not been through a fight where the tail has been bitten off.
Sometimes a pig will have its tail bitten off by another animal, like a wild boar or even another domesticated pig.
The tail needs to be at least partially curled for the pig to be considered as having a curly tail.
6. What do pigs do with their tails?
Pigs use their tails for balance and as a sort of cushion when they sit down.
They also flick their tails around, as well as wag them when they are happy.
Pigs do not use their tails to swat away flies or bees, as many people think.
Pigs like to roll around in mud and dirt, which is probably why so many mistakenly believe that they swat at pesky insects with their tails.
In some parts of the world, pigs are often seen walking on a leash with a person behind them, and their tail is used as a control mechanism.
For example, if the pig gets too close to something it doesn’t like (such as a fence or another animal), then the owner would give the pig’s tail a quick tug to pull them back away from that object.
7. Why do pigs wag their tails?
Pigs wag or fling their tails when they are happy.
This is called “dancing.”
It is not known exactly why pigs do this, but it probably has to do with the same instincts that make dogs wag their tail when they are excited or pleased.
A pig that is being talked to calmly, petted on, or brushed usually wags its tail.
Additionally, pigs will move their tails side-to-side when they eat as a way of encouraging the food to come to them.
Tails are also sometimes flicked straight up and down when pigs play or mate with one another.
8. What other animals apart from pigs have curly tails?
Now that you’ve learned some tales why do pigs have curly tails, let’s take a look at other cute animals with curly hairs?
Other animals in the world have curly tails: the rabbit and the squirrel.
The tail of a squirrel is referred to as a “brush” while the tail of a rabbit is called a “scut.”
Moreover, some dog breeds, like the Pekingese, are born with naturally curly tails.
Pugs are also born with naturally curly tails and are sometimes referred to as “pig dogs.”
9. What happens if you clip your pig’s tail?
If you cut off or clip your pig’s tail, it can cause pain and bleeding.
An animal that has had its tail cut off might not be able to balance properly, which can lead to injuries as well.
Tail-docking – carried out without an anesthetic when the piglet is three to four days old – is intended to prevent the severe injuries that can occur when pigs bite each others’ tails.
If you clip your pig’s tail, it could make it more difficult for a veterinarian to treat the animal if it gets sick or injured.
Additionally, pigs with clipped tails are less likely to be taken as pets because they look like farm pigs and not house pets.
When a pig’s tail is cut off, it does not grow back.
Because of this, you should make sure that you are very careful with your pig’s tail if you decide to cut it.
Conclusion
So why do pigs have curly tails? In conclusion, pigs are born with curly tails but can develop straight tails later on in life and, in some cases, these pigs will have naturally straighter tails.
There is a great deal of debate about when or why the tail curls and whether this phenomenon is scientifically proven or not.
Interesting Read:
Trimming Piglets’ Tails: The Hows, Whys — and Why Nots

Sarah Lane has been a farm wife since 2010 and mother of two children for nearly as long. She and her husband, Jonathan, live on a small farm in Texas where they raise dairy goats and beef cattle as well as chickens for eggs and meat. In addition to growing their own hay, straw and garden produce, the Lane family works with other nearby farms to source organic grain from which they make artisan bread sold at local farmer’s market.