Australian Rat Colours

Solid and ticked coats

close up of a ticked pet rat coat
Ticked Coat

The agouti gene (A) is a dominant gene, and causes each strand of hair to have two bands of colour, giving a ticked appearance to the coat.

The non-agouti gene (a) is a recessive gene, meaning that two copies are required to affect the phenotype. When two copies of the non-agouti gene are present (aa) each strand of hair is one solid colour.

(note that a asterisk indicates that the second gene of the pair could be either dominant or recessive to no further consequence)

Silvering

close up of a silvered pet rat coat
Silvered Coat – Image courtesy of Kristen

Silvering refers to a coat which has white hairs interspersed with coloured hairs. All blacks in Australia are silvered, some to greater degrees than others. Some are so sparsely silvered that they are hardly noticeable, whereas others are so heavily silvered they look roaned.

Silvering also occurs on other colours, such as dove and mink, however the rat is only referred to as silvered if there are enough white hairs for the silvering to be visible.

Agouti A*D*M*R*P*

 Agouti blazed rex pet rat playing in a tube
Agouti

The dominant agouti gene is present so the hairs are banded. The colours on the bands are black and orange (orange at the base and black on the tips), making the rat appear brown due to the ticked effect of the coat. Guard hairs and eyes are black.

Black aaD*M*R*P*

 Black wedge blazed variegated berkshire pet rat drinking from a water bottle
Black

As two recessive agouti genes are present, the hair is not banded and appears solid. Guard hairs and eyes are black.

Cinnamon A*mmR*P*

 Cinnamon double rex pet rat sitting on a green blanket
Cinnamon

The dominant agouti gene is present so the hairs are banded. The colour of the bands are grey and brown (grey at the base and brown on the tips). There are two recessive mink genes (mm), causing dilution of the coat to a ticked chestnut brown. Guard hairs are brown and eyes are black. Cinnamons have a mink cap when moulting into their adult coat.

Mink aammR*P*

 Mink standard coat pet rat eating a treat
Mink

As two recessive non-agouti genes are present, the hair is not banded and appears solid. There are two recessive mink genes (mm), causing dilution of the coat to a warm grey brown. Mink is a highly variable colour and can be anywhere from mid-grey to a warm brown. Guard hairs are slightly darker than the coat colour, eyes are black. Minks have a mink cap when moulting into their adult coat.

Fawn A*M*rrP*

 Fawn patchwork rex pet rat sitting on a sink
Fawn

The dominant agouti gene is present so the hairs are banded. The colour of the bands are grey and orange (grey at the base and orange on the tips) There are two recessive ruby eye genes (rr), causing dilution of the coat to a ticked rusty orange. Guard hairs are grey, eyes are diluted to ruby.

Buff aaM*rrP*

Buff - Image courtesy of Sdaji
Buff – Image courtesy of Sdaji

As two recessive agouti genes are present, the hair is not banded and appears solid. There are two recessive ruby eye genes (rr), causing dilution of the coat to a warm beige. Guard hairs match the coat, eyes are diluted to ruby.

Silverfawn A*M*R*pp

 Silverfawn standard coat pet rat eating brocolli
Silverfawn

The dominant agouti gene is present so the hairs are banded. The colours of the bands are orange and cream (cream at the base and bright orange on the tips). There are two recessive pink eye genes (pp), causing dilution of the coat to a bright orange ticked with cream. The guard hairs are diluted to creamy silver and the eyes are diluted to pink.

Champagne aaM*R*pp

 Champagne hooded pet rat sitting in a bowl
Champagne – Image courtesy of Silver Frost Rodents

As two recessive agouti genes are present, the hair is not banded and appears solid. There are two recessive pink eye genes (pp), causing dilution of the coat to a very pale cream.Guard hairs match the coat and eyes are diluted to pink.

Argente A*mmrrP*

 Argente standard coat pet rat sitting on blue towel
Argente – Photo courtesy of Guardians Gathering Rodentry

The dominant agouti gene is present so the hairs are banded. The colour of the bands are rusted orange and cream (cream at the base and rusted orange on the tips) There are two recessive mink genes (mm), causing dilution of the coat AND two recessive ruby eye genes (rr) causing further dilution. Guard hairs are orange and eyes are diluted to ruby. Argentes have a mink cap when moulting into their adult coat.

Dove aammrrP*

 Dove standard coat pet rat
Dove

As two recessive agouti genes are present, the hair is not banded and appears solid. There are two recessive mink genes (mm)AND two recessive ruby eye genes (rr) causing dilution of the coat. The effect of these two dilution genes result in a pale grey. Guard hairs are pale grey and the eyes are diluted to ruby. Doves have a mink cap when moulting into their adult coat.

Mink Champagne aammrrpp or aammR-pp

 Mink Champagne silk pet rat reaching forward off a cage
Mink Champagne

As two recessive agouti genes are present, the hair is not banded and appears solid. Either two or three of the recessive genes are present. The more dilute genes, the lighter the rat looks. An aammrrpp rat can be easily mistaken for an albino unless put right next to a true albino at which time the off-white colour of the coat is noticeable. An aammR-pp rat isn’t quite as diluted and is easily distinguishable as a mink champagne, but the coat seem ‘dirtier’ and not as warm as champagne. Guard hairs match the coat and eyes are diluted to pink. Mink Champagnes have a mink cap when moulting into their adult coat.

Albino cc

 Albino double rex pet rat nibbling a finger
Albino – PEW

The recessive albino gene is present, the hair is entirely devoid of any colour but white, so appears solid. Guard hairs are white and eyes are pink. As the albino gene complete removes all colour, it is impossible to know the rest of the genotype without either knowing the parents genotypes or breeding the albino to see what offspring is produced when paired with a partner of which the genotype is known. Also referred to as Pink Eyed White or PEW.

Black Eyed White nn

 Black eyed white baby pet rats curled up together
Black Eyed White

The BEW gene is supposedly Co-dominant. It is similar to the Albino gene in that it masks the true colour of the coat. Eyes are black, coat is white, guard hairs are white. Often the coat and ears are mismarked with smudges or splodges of colour. It is believed to be an overmarking of white, and heterozygotes often have face markings that range from headspots to lightning blazes with chin straps, and variegation in berkshire heterozygotes.


Blue dilutes

It is possible for blue to come in any of the combinations outlined above. For example, blue cinnamon, ruby eyed blue, blue mink, blue dove. Each dilute has a slightly different effect on the coat, but overall the colour is still distinguishable as blue due to the cold tint of the coat. Here are some of the possible combinations.

Blue Agouti A*ddM*R*P*

 Blue agouti rex pet rat leaning out of a cage
Blue Agouti

The dominant agouti gene is present so the hairs are banded. The colour of the bands are blue and orange (blue at the base and orange on the tips) There are two recessive blue genes (dd), causing dilution of the coat to a ticked blue and orange. Guard hairs are blue and eyes are black.

Blue aaddM*R*P*

 Blue hooded pet rat
Blue

As two recessive agouti genes are present, the hair is not banded and appears solid. There are two recessive blue genes (dd), causing dilution of the coat to a solid blue. Guard hairs match the coat and eyes are black.

Blue mink aaddmmR*P*

 Blue Mink pet rat showing his whiskers
Blue Mink

As two recessive agouti genes are present, the hair is not banded and appears solid. There are two recessive blue genes (dd) and two recessive mink genes (mm), causing dilution of the coat to a solid blue grey which is noticeably greyer in appearance than standard blue. Guard hairs match the coat and eyes are black. Blue minks have a mink cap when moulting into their adult coat.

Blue Cinnamon A*ddmmR*P*

 Blue cinnamon pet rat sitting on bath
Blue Cinnamon

The dominant agouti gene is present, so the hairs are banded. The colour of the bands are blue grey and orange (blue grey at the base and orange on the tips) There are two recessive blue genes (dd) and two recessive mink genes, causing dilution of the coat to a ticked blue grey and orange. Guard hairs match the coat and eyes are black. Blue Cinnamons have a mink cap when moulting into their adult coat.

Blue Argente A*ddmmrrP*

 blue argente rat sitting on a beige chair
Blue Argente

The dominant agouti gene is present, so the hairs are banded. The colour of the bands are blue grey and muted yellow (blue grey at the base yellow in the middle and blue on the tips) There are two recessive blue genes (dd), two recessive mink genes AND two recessive ruby eye genes, causing dilution of the coat to a ticked blue grey and muted yelow. Guard hairs match the coat and eyes are ruby. Blue Argentes have a mink cap when moulting into their adult coat.