In dogs, blue and blue merle are totally different. Blue is what most people would call grey and blue merle is a silvery colour, splashed and marbled with black (as in Rough and Smooth Collies, Shelties, Cardigan Corgis, Aussie Shepherds, etc.). There is also red merle, which ranges from a chocolatey brown colour to almost pink. Australian Cattle Dogs come in blue speckle (hence 'Blue Heelers' ) and red speckle.
As with horses, there are very few actual white German Shepherds, most are a cream colour.
There are some fascinating name for colours in dogs, such as Pepper and Salt in Schnauzers, Orange/Lemon/Blue Belton in English Setters,
Grizzle in Border Terriers.
Greyhounds and other dogs can be brindle, blue brindle, red brindle - brindle is a mix of black hairs with hairs of a lighter colour, gold, brown or grey, usually striped. We also have roan, a mixture of coloured hairs alternating with white - blue roan, orange roan, lemon roan, liver roan. Sable is where the hairs are tipped with black on a background of silver, gold, grey, fawn or tan.
Perhaps one of the most unusual is Blaireau, which is 'badger' coloured markings found in Pyrenean Mountain Dogs. Deadgrass can be straw to bracken coloured. Sedge is red gold. Wheaten is pale yellow or fawn.
Dudley is liver, brown or putty coloured. Liver is also known as brown or chocolate, and there is also Puce. Harlequin is blue or black patches on white (as in Great Danes). Isabella is a fawn colouring found in Dobermann Pinschers. Landseer is black and white as in Newfoundlands (in other countries the Landseer is a separate breed).
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