How could colouration affect behaviour in animals?

Domestication, the process when animals adapt to captivity, tends to modify the phenotype towards what is known as the “domesticated phenotype” which includes changes in reproduction, behaviour and morphology. One of the first and more striking changes is a loss of pigmentation in the coat colour, causing a white patterned plumage, skin or fur. There are many studies reporting on associations between behaviour and coat colour in different species. In general dark pigmented animals are described to be more aggressive, dominant and sexually active. There are two different types of melanin pigments, red-yellow pheomelanin and black-brown eumelanin. The melanocortin-system regulates colouration by switching the production between pheoand eumelanin. Melanocortins also bind to receptors responsible for several physiological and behaviour functions, and therefore offers a good model to explain the relationship between colouration and behaviour. Another explanation could be the close relationship between eumleanin and dopamine, a neurotransmittor known for its general effects on physiological and behaviour responses. It is also important not to forget the significance of underlying genetic effects such as linkage or pleiotropy, which could be the third explanation for the relation between two such complex traits. However, what ever causes the effects the association between behaviour and pigmentation seems to be a widespread phenomena in the animal kingdom and it is as fascinating in insects as in birds and mammals. Definition of domestication Domestication, the process by which captive animals adapt to man and the environment he provides (Price, 1999), is defined in a various numbers of ways. Rindos (1980) postulate the domestication as a symbiotic evolutionary process between humans and animals or plants, where the domestication occurs before the origin and development of agricultural systems and is the reason agricultural system develops. Contrary, Hale (1969)