What Is a Merle Boston Terrier

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What dog is known for its friendly and gentle nature? So who is that notorious four-footed buddy of humans born in a tuxedo? You undoubtedly know who it is, right?

A Boston terrier! Bostons are referred to as ‘American Gentlemen’ this nickname roots from its neat looks and the fact that it was first bred in the USA.

There are various breeds of Boston. This guide will highlight what is a Merle Boston terrier and everything about it in detail.

What Is a Merle Boston Terrier

Merles are one of the rarest breeds of the Boston terrier. That’s why even after being the rarest, they are high in demand among the buyers.

The history of Merle Boston is not much known to me. But as per the current breeding culture, a merle dog from another breed would have been bred with a Boston to achieve a ‘Merle Boston terrier.’

What Is a Merle Gene in Boston?

A Merle Boston terrier is also known as harlequin or dapple. The Merle trait comes from a gene known as the Silv gene that imparts a faded skin coat to the dog. Because of this gene infusion, the Merle Boston dogs have small eyes and suffer audio-visual impairment.

A Boston Terrier looking up

Physical Appearance and Attributes of Merle Boston Terrier

Size and Appearance

A Boston terrier is mostly compact and sturdy. This four-leg Terrier has an average height of 9-15 inches. This breed very small and light, and typically weighs around 6-25 pounds. You will need 40 Merle Boston terrier to match the average weight of a pool table which is around 1,000 pounds.

Boston terrier is closely related to bulldogs. It has a square jaw and a brachycephalic head. The eyes of a Boston terrier are round and set wide and deep-seated into the skull.

Its ‘tuxedo coat’ can be black, seal or brindle in proportion to the white markings on its face, chest, paws, or legs.

A merle Boston has a faded skin pigment and blue/odd-colored eyes, and sometimes it can have mottled patches.

Behaviorism Of Merle Boston Terrier 

Boston Terriers are very friendly and chirpy pet animals. Unlike their Irish relatives, who have an instinct of a watchdog, these pups are more on the domestic side.

Bostons believe in the language of love. That’s why it is effortless to befriend and get along with a Boston terrier.

Not only that, they are very social beings and very friendly even to strangers. Well, this may be a point to worry about as this cute little gentleman cannot distinguish a friend from a foe. That’s why as a responsible owner, one has to groom them from the very beginning about these things.

A fascinating fact about Bostons is that they are very monogamous beings. You might be surprised to know this but, Boston tends to form an extraordinary bond with only one person in their life.

When it comes to being a guard dog, size and build, strike the name of Boston from the list. Boston Terriers don’t bark a lot at anyone. The rate of barking is usually low to moderate in Terriers.

Trainability and Intelligence 

Even if a merle Boston might not be a good guard dog, they are attentive and intelligent at par. When it comes to intelligence, the Boston terrier is as smart as it looks.

They are excellent learners. A Boston terrier’s attention to detail, ability to adapt to surroundings is commendable. They can learn your schedules, likes, and dislikes and even decipher your current mood.

When their masters come up with something new, Boston often tilts their heads sideways to show that they are confused. Sounds adorable, right?

As a pet, Terriers rarely through tantrums on their owners. They are more eager to please their owner. They have a knack for quickly learning commands and grasp details.

A Boston Terrier with ears open

Genetics of Merle Boston Terrier and Their Characteristics

Allele NomenclaturePhenotype GroupCharacteristics/Traits
No insertion (m)Non-merleNo merle, wild-type
M(200-246)CrypticMost cases are non-merle with a rare chance of getting very small merle patch(es)
M(247-264)AtypicalMost cases have normal color that often produces diluted color, reddish undertones, or atypical merle appearance
M(265-269)ClassicMost cases have classic merle with a lot of merle color and patterning. Some rare cases have a minimal amount of merle.
M(270-280)HarlequinMost cases have patches of multiple shades either the same or different colors without white (tweed) or with white (harlequin)


Positive reinforcement is the best way to keep them motivated. Just like other pet animals, Bostons also like to receive treats. But beware that excess of treats can make your Boston overweight and harm its health.

Thus, motivate your Terrier with non-edible treats and rewards. However, you can give occasional itsy-bitsy treats to your sweet little gentleman for his hard work.

Exercises for Your Merle Boston Terrier

When it comes to exercising, Merle Boston terriers are not like typical sporty dogs. They aren’t fond of the ‘adrenaline rush’ and thus, can get tired due to excess fatigue.

As a card-carrying, non-sporting group member, a typical Boston would prefer enjoying its time on comfy bedding rather than playing fetch or leave in the backyard. This behavior of Terriers pushes them to put on weight.

Physical Exercises

To stay in pink of its health, your tuxedo best friend needs at least one hour of physical activity each day. This can include,

  • Thirty minutes walk at intervals. (two times a day)
  • One long and steady walk.
  • Game of fetch
  • Swimming
  • Tug of war
  • Agility courses

Mental Exercises

It is observed that dogs can also evolve with technology. Today there are many dogs on the internet that are well-versed with daily gadgets.

Since Boston Terriers can pick details, they can also learn these amazing kinds of stuff. For its mental development, you can introduce various tricks and mind games to your Boston terrier. These games may include:

  • Nursery puzzles for kids.
  • Identification and recognition of characters.
  • Puzzle toys that are especially for dogs.
  • And lastly, work on their coordination and communication skills. For example, you can introduce a new word each day that revolves around its daily life. Moreover, you can teach phrases like, ‘sit down, ‘handshake,’ ‘stand up to your dog for effective communication.

Health and Life Expectancy

The average life of a Merle Boston Terrier is usually 11-15 years. However, a Boston can be short-lived depending upon its breed and health condition.

Terriers that are bred in an unhealthy manner have a shorter life due to their chronic ailment. Most of the Merle Boston terrier experiences a few severe health problems once in their lives.

But it isn’t the case with this breed only; every species has its own set of medical issues in their lives.

A Boston Terrier lying down while looking at the right

Diseases That Are Common in Merle Boston Terrier

From the above, you might know that the Merle gene causes deafness and visual impairment in Boston. But, apart from this, your dog can go through other diseases as well, which need equal attention.

In Merle Bostons, Corneal ulcers, cataracts, and cherry eyes are some of the most known ailments that they go through once in a life. However, it is not necessary that every Boston would go through one of the above; one can also live a very healthy life without any long-lasting medical problem.

Patellar luxation, also known as a knee problem, is quite common in dogs of every breed. However, it is said that Medial luxation is more profound than lateral luxation in small dogs like Bostons.

In Medial Patella luxation, the ‘knee cap’ dislocates from its original position. Thus, it affects the locomotion of the animal and results in excess pain, especially in the initial days.

Apart from knee issues, digestive problems, deafness, and reverse sneezing are few chronic issues among different breeds of Boston terrier.

These issues are curable to some extent and can be managed with treatment and TLC. Along with these, heart murmurs and brain tumors are two fatal ailments among this breed. 

Why Breeding Two Merle Boston Terriers Can Be Dangerous?

‘When two like things are put together, the likelihood of having the same output increases.’ 

The same is the case with Merle Boston Terriers. The Merle gene causes a genetic mutation in the breed that causes a ‘Merle coat’ and other specific characters in the dog. But, the gene is also responsible for affecting the health of the Boston terrier negatively.

When a breeder crosses two Merle Boston terriers together, the resultant pup can have ‘double Merles’ or ‘lethal whites.’ This condition often results in partial to complete eye and ear deformities. It won’t be wrong to say that double Merle Bostons can be completely blind or deaf.

There is a 25% chance that the results will be a double Merle dog when two Merle Bostons are bred together as per genetics. Since two merle genes are put together, the risk factors rise to double than before.

Visual Impairment in Merle Boston Terrier

Apart from complete deafness, double merle Boston terriers can suffer from visual impairment like,

  1. Microphthalmia – This is a condition where the dogs have smaller eyes than the usual eye size of the standard breed.
  2. Anophthalmia – This is a condition where the dog has tiny eyes. The eye size is so tiny that it seems like there is no eye at all.

A lot of other folds are left to unravel about the issues regarding ‘double Merle’ Bostons. Though if someone is breeding them for the sole purpose of money, then it is unfair to the rights of those innocent little pups. 

A Boston Terrier puppy looking at the camera

Related Questions

How Can I Prevent Double Merle Boston Terrier?

As a buyer and a responsible pet owner, you can step forward and raise awareness about this topic as much as possible. Breeding two Merle Bostons are not just selfish but a negation to one’s right to a healthy life.

You can make your fellow buyers aware of these greedy breeders who sell these pups as rare species at a higher price without revealing the consequences.

Are Merle Boston Terriers Healthy?

Merle Boston Terriers are not healthy. First, the gene carrying the Merle coat color also is prone to eye and ear disorders.

Hence, you often see Merle Boston Terriers with smaller than normal eyes, abnormal eye or iris shape, missing eyes, and even deafness.

Do All Merle Dogs Have Health Problems?

Not all Merle dogs have health problems. The Double Merle is the only combination that has a high chance of getting health problems. Double Merle

Boston Terrier Colors And Patterns | Types Of Boston Terrier colours


Merle gene infusion in your Boston can be an eye-catching aesthetic because of its faded color. However, even if the merle trait might look pleasing and beautiful to you, your dog is the one who has to face the consequences.

The merle gene can cause visual impairment and hence, often results in cataracts among the different breeds of dogs.

A study reveals that Primary hereditary Cataract (PHC) is the leading cause of blindness among Boston terriers. In addition, when a Merle Boston has a cataract, its blood relatives (offspring) have a higher chance of having cataracts and blindness even if they don’t inherit the ‘Merle character.’

Thus, as an owner, you have to be careful about the breeding, or else medical issues may pass down the line.