A Dudley Lab is a Labrador retriever that lacks pigmentation on the eyes, eye rims, muzzle, and nose. This is a genetic trait that is very rare and affects only the yellow Labrador retrievers.
This trait can't be considered as an abnormality of the genes.
Usually yellow Labs have black pigmentation on those areas while Dudley Labs don't.
The coats of Labrador dogs have two distinct yellows. They differ in the genetic combination of colour or what is called as genotypes.
If a yellow Labrador retriever has a bloodline of one or two genes that are programmed for a black hue, then that dog will most likely have black pigments that can vary in intensity.
On the other hand, those yellow Labs which have a lineage of genes that are encoded for chocolate colours then most likely that dog will have a chocolate or liver pigment which is also known as Dudley.
These labs vary in colour, such as light flesh, light yellow, dark yellow, dark brown and even red.
These combinations depend on the breeding and on the parents' colour.
Take for instance, two Labs bred together. There is a tendency that the offspring is a combination of both liver-pigmented yellow and black pigmented yellow.
Some Labs have pinkish nose, which is commonly referred to some people as snow nose or winter nose. Many of the yellow Labs have dark noses during the summers and would just eventually fade during the winters. This cycle is not totally understood and can been seen in other northern breeds such as Malamutes and Huskies.
To determine if it is just a snow nose or if it is really a Dudley Lab, all you have to do is to check the gum tissue and the eye rims, which should also lack the pigmentation.
Typically this kind of Labrador retriever will also have tan or light pink skin while other Labs have black pigments in these areas. Additionally, a true Dudley has the tendency to sunburn easily, so they should not be exposed too much to the sunlight.
The pigment on the nose of yellow Labs can vary. Some yellow Labs have slight black pigment around the muzzle and eyes. Some have pigmented nose that begins to fade as puppies (usually around 2 years of age) and will eventually become black again until they are 8 years old and above.
Many say that this kind of Labrador retriever has a yellow liver pigment. In a Labrador retriever book I have read, the nose of one of these dogs is defined as flesh coloured. Another source defines them as pink and according to this same source, a yellow lab with light or dark chocolate pigment is not a Dudley.
As for the American Kennel Club standards, the Dudley has a thoroughly pink nose and lacks any pigment.
Lack of pigments in these yellow Lab dogs doesn't mean that they can't be a beloved pet. They can still make wonderful companions and lifelong members of the family.