Mismarks and Blue Eyes
Lesson #9 will be based on the mismarks of head and blue eyes in Boston Terriers.
Mismark is a term used when describing markings of the head of a Boston Terrier that are not the
traditional mask, white muzzle band, and blaze between the eyes and over the dome of the head.  Boston
Terriers are notorious for no two being exactly the same in personality and in markings. Facial and head
markings have a lot to do with expression of the Boston Terrier.  It has been postulated that there may be a
separate gene in the Boston Terrier that attributes markings, or lack of, on the head. This has not been
proven.  There have been instances when two perfect facial/head marked Boston Terriers produced
puppies that were perfectly tuxedo saddled over the body but are lacking AKC standard markings on the

Blue eyes is a trait in the Boston Terrier that can seem to crop up out of nowhere.  A sire and a dam who
lack blue eyes can produce puppies with blue eyes just as a sire and a dam each having a blue eye(s) can
produce a litter with no puppies having blue eyes. There are even Boston Terriers with "cracked blue
eyes" where part of the eye is blue. The gene for blue eyes is not yet known.  There is not much theory
behind blue eyes either.  At times, mismarks and blue eyes go hand in hand.  It would almost seem as
though just about any Boston Terrier puppy born has the geneology to have one or two blue eyes. Blue
eyes in Boston Terriers is either a preference of fanciers to have, not to have, or to some it does not
matter.  On the other hand Boston Terriers are known for their expression and when a blue eye is present
there does seem to be a lacking in that expression, however, beauty is in the eye of the beholder.

It is important to note that there are opinions that Boston Terriers with all white heads or blue eyes are
automatically ruled out as being deaf when this is not always the case.  As stated in Lesson #8, a
predominance of white, even on the head, is not necessarily a reason for being deaf, neither is a blue eye.  
However, if the puppy does have white ears, and pigment lacking within the inner ear canal, the chance of
said puppy being deaf is much greater.

As the photos below depict, mismarks and blue eyes can be produce in any color or pattern of Boston
Mismarks and Blue Eyes
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