What colors can Aussie noses be?
The nose in blacks and blue merles must be black and reds are to have liver colored noses. Under the ASCA standard, pink on the nose in a dog one year or older is considered a fault and a Dudley (entirely pink) nose is a disqualification. The AKC standard allows merles to have “small pink spots” not to exceed a quarter of the nose surface after a year of age. More than that after a year is considered a serious fault. A black nose on a red appearing dog is a red flag that he may actually be a sable or a yellow, both disqualifying colors.
What do people mean when they say a dog’s nose is “Dudley” or “butterfly?”
A Dudley nose is pink (no pigment.) This is very unusual in Aussies but will sometimes be seen in homozygous (“double”) merles. “Butterfly” refers to a nose that has an unpigmented (pink) area across the front. The term probably arose because these pink patches sometimes are vaguely butterfly-shaped.
Unpigmented areas on the nose are undesirable because they are more subject to sun damage than a pigmented nose would be. In addition, unpigmented noses can be less acute at scenting—though even a Dudley-nosed dog has a far better sense of smell than any human.
What if a dog has the wrong color nose?
Aside from the issue of pink on the nose, generally seen only in merles and addressed above, black and blue merle dogs can only have black noses and red/red merle dogs can only have liver noses. A black dog might have grey, brown or even pinkish pigment on its nose due to environmental causes, this is often called “snow nose” but is not strictly a cold or snowy weather issue. Plastic feed bowls and other sources have been considered as causes.
However if a “”red” Aussie has a black nose it is not truly B-locus red. Other genes can produce a red dog that might have a black base (think Irish Setters and yellow Labs). If you have a dog like this some genetic testing is in order to identify the genes involved and, possibly, the parentage.