The Debate Over the Blue Eyed Pitbull Explained
There’s no denying that crystal blue eyes in dogs are a rarity and are certainly beautiful to look at. More often than not, breeders even charge a premium on puppies with these unique blue eyes, as the demand for their adoption is greater than those with the much more common brown eyes.
However, there is a controversy around blue eyed pitbulls, making them less than desirable in their own community. Is it considered normal for Pitbull puppies to have these blue eyes and what causes them in the first place?
Should blue eyes in pitbulls be seen as a desirable trait or the result of a genetic mutation that makes them less so in the eyes of the APBT community? In this article, we take a look at what causes this blue eyed phenomenon in the pitbull.
View Table of Contents
- What Is Considered a Pitbull?
- Why Do Pitbulls Have Blue Eyes?
- Why Do Blue Eyes Vanish in Puppies?
- Are Blue Eyed Pitbulls Rare?
- Blue Eyed Pitbull Health Issues
- Breeding for Appearance
- The Blue Eyed Pitbull’s Appearance
- Why Pitbulls Don’t Actually Have Blue Eyes
- Why Are Blue Eyes Considered To Be a Negative Trait in Pitbulls?
What Is Considered a Pitbull?
First, we must establish what defines a pitbull. As you may or may not know, a pitbull is not actually a breed itself but a term covering several dogs. This includes the American Pitbull Terrier, American Staffordshire Terrier, American Bully, and the Staffordshire Bull Terrier.
The American Bulldog, along with any crossbred dog that shares certain physical characteristics with these breeds, are also sometimes considered pitbulls. So really, the term “pitbull” is not a breed at all, but a label that is used for dogs who descend from Bulldogs and Terriers.
In this article, the word “pitbull” will be used to refer to all of the above due to the fact that they all share the same origins and genetic makeup of the “pitbull.”
Why Do Pitbulls Have Blue Eyes?
Let’s break down the reason beyond why pitbulls develop those crystal blue eyes.
You’ll notice that the vast majority of dogs have a brown eye color, which is known as their “default” color.
So, what causes the pitbull’s eye color to stray from their default brown? Genetics, pigmentation, and health issues are all possible factors that will change your Pitbull’s eye color, with genetics being the most prominent.
If a pitbull has a long lineage of these icy blue eyes, there is a good chance that they are going to inherit them too. It’s also important to note that the vast majority of puppies of all breeds are born with blue eyes. In most cases, their eyes will darken as they age, completely disappearing when they’re out of the puppy stage.
The following are the three main reasons why pitbulls have blue eyes:
The Merle Gene
If a pitbull carries the merle gene, they are much more likely to develop blue eyes than a dog that does not. The Merle gene causes a random pigment dilution or lightening of the nose, eyes, and fur, allowing any of these areas to be affected. This is why you’ll often see dogs with this gene displaying a beautiful “Merle” coat pattern. Of course, just because a dog is a carrier of the Merle gene doesn’t mean that it will develop blue eyes.
Unfortunately, dogs with the Merle gene are prone to health issues like deafness and blindness, which we will discuss later on. A breed that carries a double Merle gene (MM) is extremely prone to these genetic diseases, so Merles must never be bred together. A heterozygous merle (Mm) is considered much less likely to develop health issues than a double Merle.
It’s interesting to note that a pitbull with a Merle coat pattern is actually excluded from the APBT breed standard. If a pitbull carries the Merle gene, it is questioned whether or not they are purebred, as this gene is thought to originate from breeds outside of what is considered a pitbull.
The ALX4 Gene
In humans, blue eyes are caused by a genetic variation between a pair of HERC2 and OCA2 in the human genome. A study carried out by Embark Veterinary has discovered that a genetic mutation near the gene known as ALX4 on canine chromosome 18 is, in some cases, responsible for blue eyes in all dog breeds, including those classified as pitbulls.
Melanin (a dark brown to black pigment occurring in the hair, skin, and eyes in people and animals) levels may also be responsible for the blue eyed Pitt. Usually, dogs with a higher level of melanin in their iris will have brown eyes, while dogs with a lower concentration of melanin will have lighter eyes. This loss of pigmentation due to low melanin levels is also said to be due to the above mentioned Merle gene.
Why Do Blue Eyes Vanish in Puppies?
As mentioned, the vast majority of puppies are born with blue eyes, which gradually turn darker as they progress in puppyhood.
But how is this possible? While dogs who carry the Merle gene will sometimes retain low melanin levels that will not allow their eye color to deepen, all puppies are born with low levels of melanin.
In fact, melanin production only begins a few weeks after birth. While some puppies still manage to be born with pigmented fur colors, others fur won’t begin to darken until they get older.
It won’t be until your puppy reaches about four months of age that you’ll truly know what their adult eye and coat color will be, as these first few months are crucial to melanin development.
It has been said that the coat color can influence the eye color, as dogs with an extremely dark coat may have melanin levels that are so high that developing blue eyes would be impossible.
Are Blue Eyed Pitbulls Rare?
Blue eyed pitbull puppies are in themselves not rare due to their still rising melanin levels. Breeders that charge a premium for puppies with blue eyes will often take advantage of this fact, charging a premium for their puppies with lingering blue eyes, labeling them “rare.”
However, it is almost impossible to know before four months of age whether their eyes will darken, and more often than not, they do. Blue eyed adult pitbulls are much rarer.
Blue Eyed Pitbull Health Issues
From a genetic point of view, blue eyes themselves are usually not an indication of health issues, and it is perfectly possible to have a healthy blue eyed pitbull puppy. Having said this, the potential gene mutations behind their blue eyes may be what increases the likelihood of certain health issues, making these blue eyed pitbulls more susceptible to health issues than a brown-eyed Pitbull.
It is said that dogs with white or merle coats are predisposed to congenital deafness. This is because dogs who are carriers of the Merle and/or Piebald (a pattern of less symmetrical white spotting) genes are both at risk for hearing loss.
Congenital deafness in itself is linked to the merle gene, but the Piebald gene is also known to cause deafness due to the lack of melanin-producing cells within the inner ear. Therefore, if your pitbull pup does have blue eyes or a white coat due to the Merle gene or has a spotted color coat due to the Piebald gene, they may be at a higher risk of hearing loss.
A pitbull can be tested as young as six weeks old for congenital deafness, using the Brainstem auditory evoked response (BAER) test. This electro-diagnostic test evaluates the external ear canal components, middle/inner ear cavities, cranial nerve, and selected areas of the brainstem.
It is used to evaluate the hearing of dogs, cats, and other domestic animals. It’s important to rule out congenital deafness at such a young age, as hearing impaired pitbulls will need extra care and training to not suffer accidents.
The Merle gene is again responsible for pitbulls developing vision defects or possible blindness. However, if only one of a dog’s parents carries the Merle gene, vision defects are unlikely to occur.
Dogs with a double Merle gene (MM) are much more likely to eventually go blind, which is why it’s important to ensure that dogs that both carry this gene are not bred. Dogs with the (MM) gene are much more likely to develop serious health issues and defects, making blindness likely occur. Animals that do carry the double Merle gene are usually white in color.
Pitbulls also occasionally develop other eye conditions that are not necessarily known to be linked to blue eyes. These include:
- Hereditary cataracts
- Distichiasis (double eyelashes)
- PHPV (persistent hyperplastic primary vitreous)
Albinism is another side effect of the Merle gene, as these dogs lack the necessary genes to produce melanin at all, which is more common in dogs with the double Merle (MM) gene. The vast majority of pitbulls who suffer from congenital deafness or blindness have some if not all white pigmentation in their coats.
Breeding for Appearance
Breeding for appearance can be incredibly dangerous to a dog’s future health if both parents carry the Merle gene. An inexperienced or negligent breeder may breed two pitbulls with that icy blue eye color to have a much higher likelihood that the resulting puppies will inherit this eye color.
Although the breeder is very likely to get their wish, they are not looking out for their puppies’ future wellbeing. These puppies will potentially have a number of irreversible health issues throughout their lifetime due to this focus on a blue eyed appearance.
The Blue Eyed Pitbull’s Appearance
Does a pitbull with blue eyes vary in appearance to brown-eyed pitbulls? Besides the noticeable difference in eye color, the only other difference may be a lack of melanin in their coat, causing them to have a white fur color or a fur color that includes white and brown patches. Regardless of coat and eye color, pitbulls will all have a similar stocky, muscular build, with a smooth coat.
The size and weight of the pitbull fluctuate due to the breed’s mix between different types of Bulldogs and Terriers, but they will all generally have a wide, square-like head and jaw, with a short, whip-like, pointed tail.
Why Pitbulls Don’t Actually Have Blue Eyes
You may be wondering what this entire article has been about if pitbulls do not actually have blue eyes! It’s interesting to note that any blue eyed dog does not have blue eyes at all but that their blue color reflects, much in the same way as the sky and water get their color from a reflection.
Dogs with blue-eyes, in fact, have a completely colorless iris. This means that the light that enters the pitbull’s eyes is scattered back into the atmosphere and can create the appearance of blue eyes. You learn something new every day!
Why Are Blue Eyes Considered To Be a Negative Trait in Pitbulls?
Overall, the reason why blue eyes are considered to be such a negative trait in pitbulls is two-fold. The first reason is that the Merle gene is not thought to have originated with the Pitbull breed, which questions whether the dog is purebred.
However, the Merle gene is most undesirable because it can cause several health issues for your dog, especially if they carry the double Merle (MM) gene. A double Merle gene will often cause blindness and congenital deafness. If a breeder allows two dogs with the Merle gene to breed, this will seriously bring the breeder’s validity into question.
Due to the fact that adult blue eyed pitbulls are so uncommon, breeders should provide detailed health certificates stating that the parents of the litter do not carry the Merle gene. If one of the parents carries the Merle gene and the other does not, it’s still important to be transparent about this information to someone searching for a purebred pitbull, who they may wish to breed themselves later.