English Mastiff Color Chart

An overview of English Mastiff colors and their genetics.

English Mastiff Color Chart EmEm kyky AyAy fawn apricot sable

English Mastiff Color Chart EmEm kbr AyAy brindle

English Mastiff Color Overview

A short discussion of breed standard patterns in the English Mastiff:

Sable

Mastiffs have a clear sable pattern (k^y/k^y A^y/A^y) in shades from light fawn to red apricot.

They always have a black mask (E^m/E^m).

E LOCUS	K LOCUS	A LOCUS
E^m/E^m	k^y/k^y	A^y/A^y

Brindle

Brindle Mastiffs also have a clear sable pattern (A^y/A^y) and a black mask (E^m/E^m).

But they also have black brindle striping on top of their pattern (k^br/k^br or k^br/k^y).

E LOCUS	K LOCUS	A LOCUS
E^m/E^m	k^br/-	A^y/A^y

English Mastiff Color Genetics Summary

All breeds select for certain patterns and against others. The only pattern an English Mastiff can have according to its breed standard is a black-based sable with a black mask and with or without brindle.

As a consequence, English Mastiffs only have some of the alleles associated with canine coat colors.

These are color traits known to occur in Mastiffs:

E-LOCUS	E^m = melanistic mask E = normal pattern
K-LOCUS	k^br = brindle k^y = normal pattern
A-LOCUS	A^y = sable A^ys = shaded sable (rare)
B-LOCUS	B = black
D-LOCUS	D = normal pigment
S-LOCUS	S = no spotting s^P = piebald spotting
M-LOCUS	m = non-merle

English Mastiff Colors

English Mastiff coat colors are fairly straightforward.

Eumelanin

All English Mastiffs are fixed for non-diluted black eumelanin (B/B D/D).

Their mask, their brindle striping (if present), their nose, eye rims, and lips will be black.

Phaeomelanin

The phaeomelanin comes in a range of shades from a light yellow “fawn” to a more orange-reddish “apricot“. But there is no clear definition where on this gradual scale a fawn turns into an apricot dog.

English Mastiff Color Chart fawn black mask

White Spotting

Residual white can cause some chest white or the odd white paw.

But any white spotting that goes beyond a small white patch on the chest is considered a mismark in this breed.

A small patch of white on the chest is permitted.

Faults – Excessive white on the chest or white on any other part of the body.
Mastiff AKC breed standard

Excessive white on body, chest or feet is unacceptable.
Mastiff FCI breed standard

Both of these dogs have an excessive white “tie” reaching from chest to throat:

English Mastiff Color Chart brindle white chest patch

English Mastiff Color Chart brindle white markings

On top of that, piebald spotting also does occur at a low frequency in Mastiffs^[3]. And though likely selected for minimal expression in heterozygous dogs (S/s^P) it might still cause “too much white” overall.

And there is a chance for minimal whitehead expression also being in the breed.

Eye Color

The ideal Mastiff should have dark brown eyes.

Color of eyes brown, the darker the better, and showing no haw.

Light eyes or a predatory expression is undesirable.
Mastiff AKC breed standard

Colour hazel brown, darker the better, […]
Mastiff FCI breed standard

Nose Color

All English Mastiffs produce black eumelanin which can be observed in their nose pigment.

According to the AKC standard, “…the blacker the better…“.

English Mastiff Patterns

What patterns can Mastiffs have?

E^m/E^m
- A^y/A^y
  - k^y/k^y
    - sable
  - k^br/-
    - brindle

A Locus

Mastiffs are fixed for a sable pattern (A^y/A^y).

With a phaeomelanin intensity ideally somewhere between a light “fawn” and an orangey “apricot“.

K Locus

The sable pattern can come with either clear (k^y/k^y) or brindled (k^br/-) phaeomelanin-pigmented areas.

Brindle patterns will cause moderate to dense black striping on top of the sable base coat.

Interestingly, the AKC standard requires that a Mastiff be “completely covered with very dark stripes,” indicating a preference against overly sparse patterns and perhaps even the odd seal brindle dog.

English Mastiff Color Chart light brindle

English Mastiff Color Chart sable brindle

English Mastiff Color Chart dark brindle

E Locus

Mastiffs are essentially fixed for a black mask (E^m/E^m) on top of their sable or brindle pattern.

Ideally, the mask should be richly pigmented and cover the muzzle and eyes. Black masks also tend to cause black hairs an the ears, which is even part of the Mastiff breed standards.

Some Mastiffs express a slightly extended mask that can reach up the forehead or even cause some dark shading on the chest and lower legs.

English Mastiff Color Chart large black mask

English Mastiff Color Chart extended mask

But the wild type allele (E) also occurs in the Mastiff breed^[3].

Puppies with two copies (E/E) will not have a melanistic mask. However, due to the very low frequency, it’s highly unlikely to breed from two carriers (E^m/E) by accident.

Muzzle, ears, and nose must be dark in color, the blacker the better, with similar color tone around the eye orbits and extending upward between them.
Mastiff AKC breed standard

In any case, muzzle, ears and nose should be black with black around eye rims, and extending upwards between them. Mastiff FCI breed standard

Mismarks

These are some non-standard colors that may be possible in the English Mastiff breed:

Dogs heterozygous for piebald spotting (S/s^P) may express anything from minimal white to a pseudo-Irish pattern. Dogs with two copies of piebald spotting (s^P/s^P) may havevwhite markings on their chest, throat, paws, legs, muzzle, body, or tail.

Mastiffs born with two copies of the E locus wild type allele (E/E) will not have a black mask.

Dogs with two copies of shaded sable (A^ys/A^ys) might keep some of their black puppy shading and grow black-tipped hairs along the topline.