Does the colour of a dog’s fur really say something about their behaviour?

Well yes it can!

Where does the colour come from?

Dogs come in all different types of colours these days, even within the same breed you can get different colours. The colours come from 2 different types of pigment – Eumelanin and Pheomelanin. Eumelanin gives black fur and Pheomelanin gives red, yellow and brown fur.

Dogs did not always come in so many colours. Wolves, as we know, are not found in this many colours. The many different colours in a dog fur was created throughout the dogs’ domestication. In fact, the changes in the dog’s fur was the first signs that domestication had begun. But not only did they change fur colour they also started losing their colour. Throughout the dog’s domestication the offspring started getting little white spots in their fur. This was linked to Eumelanin slowly being decreased and then through generations evolved into offspring being completely white individuals.

The Fox experiment


The geneticist Belyayev and his team was interested in what happens when you try to domesticate a species, in this case a fox ( Watch more about the experiment here: https://www.youtube.com/watch?v=HsIibD-TLcM).

Belyayev and his team decided to see if they could explain what happens both to an animal’s genetics but also behaviour during domestication. They captured foxes and bred them. After each breeding they would pick the tamest offspring and make them next in line to breed. Then they would again pick the tamest individuals and have them breed and that continued over many generations.

By picking out the tamest individuals, aka the least afraid and aggressive, and breeding them, they found that after a few generations the offspring started to have white spots in their fur. The white seemed to increase after every new generation. What is interesting here is that Belyayev and his team picked the tamest individuals for breeding and ended up affecting other aspects of the foxes physical appearances. In this case tameness is related to loss of pigmentation. The fact that the foxes started getting white spots in their fur is not surprising as a gene often codes for more than one thing. In this case the gene that coded for tameness also coded for pigmentation.

Although no one knows how exactly this happens, the physiology behind might be able to explain why this loss of pigmentation affects a dog’s behaviour. The production for Eumelanin and Dopamine are related in the body. Dopamine has a big influence in how the brain works in social contexts making it plausible that by decreasing the production of Eumelanin you also affect the Dopamine production, changing the way the brain works and thereby affecting the way an animal behaves (Read here about the Oxytocin effect on dogs).  

The red coloured Cockers

A study in Spain performed a behaviour study on Cocker Spaniels. They found that red Cocker Spaniels showed more aggression to people then black or mixed coloured Cocker Spaniels. Here, the gene coding for a higher risk of developing aggression is also the gene coding for pigmentation.

Risk of disease


Science has also found that certain colours are correlated with risk of certain diseases. This is the case for Australian Shepherds who are born white but also deaf. They are missing the pigment Eumelanin who not only gives the black colour but also has a specific function in the inner ear. Without Eumelanin the white dogs go deaf.

This proves that the fur colour of your dog can have an affect on his/her behaviour and that we as owners need to take that into consideration when we work with our dogs (Read here how you should train your dog).


Pérez-Guisado, J. et al. 2006. Heritability of dominant-aggressive behaviour in English Cocker Spaniels. Applied Animal Behaviour Science 100, 219-227.

Podberscek, A.L., Serpell, J.A. 1996. The English Cocker Spaniel : preliminary findings on aggressive behaviour. Applied Animal Behaviour Science 47, 75-89.

Trut, L. et al. 2009. Animal evolution during domestication: the domesticated fox as a model. Bioessays 31, 349-360.

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