Variation in tameness among red junglefowls (Gallus gallus) induces variation in activity related behaviours : Exploring the basis of early domestication

The mechanisms behind early domestication of animals are still unknown and an important question is how the changes leading to what is called the domesticated phenotype have developed. It has been suggested that the domestication process has been based on tameness of animals, and that tameness is genetically correlated to other traits. This study aimed to assess whether selection based on tameness induces changes in undisturbed behaviours related to general activity in the red junglefowl (Gallus gallus) housed in semi-natural environments. Two strains of red junglefowl, selected for high and low fear of humans respectively, were studied and compared in terms of general activity. It was found that there was a selection effect on exploratory behaviour and activity, with low fear-birds being more explorative and more active, an interaction effect of selection and sex on feather preening, with high fear-males preening more, and no selection effect on comfort behaviour. Results from this study indicate that tameness is genetically correlated to exploratory behaviour, activity and feather preening in the red junglefowl. These results support the suggestion that the early domestication process was based on tameness and that genetic correlations between tameness and other traits led to the phenotypic variation that is today seen in domestic animals