Why do dogs have tails? animal experts explain

Of all the things we love about dogs (and there are a lot), their cute little faces and wagging tails take the cake. You probably know that your dog is telling you something with its tail, whether it’s the “OMG, you’re home!” of an excited wag or the “Back off, man” of a tail held high and stiff. Mood indicators aside, have you ever wondered, “Why do dogs have tails?” E.g. wagging the tail to a certain side?

As it turns out, dogs with curly tails, long and bushy tails, and even naturally curved tails have these appendages for many reasons. We asked pet experts to satisfy our curiosity. Here’s what they had to say about why dogs have tails.

What are dog tails made of?

“A dog’s tail is basically an interlocking, flexible core of bone that is an extension of its back[bone], wrapped in muscle and covered with skin. There is a rich supply of blood vessels and nerves within it,” explains veterinarian Matthew McCarthy, DVM, founder of Juniper Valley Animal Hospital in Middle Village, New York. A dog uses the muscles in its tail to wag, curl, raise, lower, and twist it.

But that’s just the basics.

There is a seemingly endless number of ways these components work together to form a variety of sizes and shapes, whether the tail is attached to a purebred or a cute mongrel. “Dogs have the greatest morphological diversity of any mammal,” says Dr. McCarthy. “For example, all horses are basically the same, except for size. Same goes for pigs, humans, etc. But an Irish wolfhound and a miniature Pugapoo are still related.”

Why do dogs have tails?

Dogs have tails for three main reasons: They aid in a dog’s balance and movement. They help some dogs stay warm. And they’re one way a dog can communicate with others, including you.

Tails help balance

Tails provide dogs with an important balance when navigating and jumping through tight spaces. When they jump to clear something, they throw their tails up, which helps with the trajectory of the jump and hopefully helps them land on their front feet.

And like an oar, a tail helps a dog turn quickly while running or swimming. “By intentionally swinging the tail to one side or the other in the opposite direction to any tilt of the body, dogs maintain their balance, much like a circus tightrope walker uses a balance bar,” says Dr. McCarthy.

Tails provide warmth

When it’s too cold for dogs to go outside, some northern breeds, like the Shiba Inu and Siberian Husky, use their heavily haired tails to cover their nose and face to stay warm.

Tails help with communication

We know dogs have the mechanics of moving their tails. But can you control them? “A dog’s tail is more like our eyebrows — they’re responsible for carrying our facial expressions outward, but slightly beyond our conscious control,” says Dr. McCarthy.

dogs can consciously controls the muscles that move the tail, but generally it’s basically on autopilot, driven by canine instinct, says Jamie Freyer, DVM, a veterinarian at Veterinarians.org.

Dogs begin conveying messages through their tails from a young age. “After just a few weeks, puppies begin to use their tails to send signals to their mother and littermates, and later, [they signal] their packmates,” says Dr. McCarthy.

When it comes to communicating with other dogs, tails send clear messages of dominance and submission. Tails carried high release more of the dog’s natural scent from the anal glands and are typically a sign of dominance. Submissive dogs trying to keep a low profile carry their tails lower to mask the scent.

Do all dogs have tails?

If you’re a dog connoisseur, you might have noticed that some have longer tails while others have something of a stump. There are mutliple reasons for this. Some puppies have their tails surgically amputated in a process called tail docking—more on that later. Other dogs are born that way. Thanks to a mutation, almost non-existent (or curved) tails can occur naturally.

You’d think that short-legged dogs, like Pembroke Welsh Corgis or fox-like Schipperkes, would need tails just like other breeds. Yet they (and others) seem to get by without them. In fact, the Bobtailed Jack Russell Terrier is one of the fastest dogs in the world. And naturally bobtailed (or surgically cropped) dogs perform exceptionally well in agility competitions, hunting, retrieving, and herding.

What gives? It remains a mystery. “There are no published scientific studies comparing the locomotion of dogs with a docked tail versus those that are not,” says Dr. McCarthy. “Possibly dogs are just so good at these activities that slight performance deficits are not readily recognized by short tails.”

Why do dogs have their tails cut off?

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The short version: Some pet owners choose to have surgery for purely cosmetic reasons. Others believe that docking the tail prevents injury, particularly in hunting breeds that may injure their tails running through dense undergrowth.

However, according to the American Veterinary Medical Association, there is no substantive research to back up these claims. It states that the potential for injury is no justification for having the surgery performed. Docking is painful and can have long-term effects on how a dog processes and perceives pain later in life and can interfere with communication with other dogs.

Although not as popular a practice today as it was in the past, docking still occurs. Some of the most popular dog breeds, like the Boxer, Doberman Pinscher, and Yorkshire Terrier, naturally have longer tails but may have docked them when they are newborns.

Of course, there are times when it is medically necessary to amputate the tail. “If a dog breaks its tail, is constantly traumatizing it, or suffers what is known as a ‘degloving injury’ where the skin peels off, generally due to a traumatic injury, it may be medically necessary to amputate the tail up to the height of of the injury,” says Dr. Freyer.

Dogs undergoing this procedure are anesthetized, prescribed appropriate pain medication, and recover reasonably well, she says.

How do dogs without a tail communicate?

“Dogs without a tail may have a little more difficulty fully communicating their state of mind to other dogs, who may also find it more difficult to interpret a message from a dog without a tail,” says Dr. Freyer. Still, she to do Express oneself.

Short-tailed breeds often rely on canine facial expressions, their ears, and vocalizations to communicate. They may not have a dick, but that doesn’t stop them from having fun. “The wiggle starts at the chest or shoulders, and if it’s a French bulldog, the wiggle starts at the ears,” says Dr. Freyer.

Communication failures may still occur. according to dr McCarthy, several studies have shown that dogs with short or absent tails are twice as likely to have aggressive encounters with other dogs than dogs with longer, more visible tails. If you have a dog with a short tail, be sure to closely monitor their interactions with other dogs and follow dog etiquette rules, especially when dining out or meeting at the dog park.

Why do dogs have tails and humans don’t?

A tail seems like a great appendage, so why don’t humans have one? In fact, we did – millions of years ago. Over time, the tails disappeared.

Well, not quite. We still have a tail for about the first eight weeks of embryonic development, but we lose it in a process called apoptosis – a programmed cell death that is part of the development of multicellular life. Although extremely rare, a gene-regulated snafu could allow a human to be born with a tail.

But most of us are content to appreciate our four-legged friends’ tails instead. Their tails, their long noses, their big ears… You get the picture.

Sources:

• Matthew McCarthy, DVM, veterinarian and founder of Juniper Valley Animal Hospital in Middle Village, New York
• Jamie Freyer, DVM, Veterinarian at Veterinarians.org.
• VCA Animal Hospitals: “Interpreting Tail Wags in Dogs”
• nature education: “Atavism: Embryology, Development and Evolution”
• American Veterinary Medical Association: “Frequently Asked Questions About Dog Tail Docking”
• Live Science: “Why don’t humans have tails?”
• animals: “Tail docking in puppies: reassessing the role of the tail in communication, acute pain caused by docking, and the interpretation of behavioral responses”