Abstract: | Studies on 7-day-old and 8-month-old female silver foxes indicate that additional photostimulation affects to a various extent morphological and functional condition of the adrenal cortex in animals selected and unselected for the domestication type of behaviour. In relatively wild foxes, additional illumination stimulated the activity of the reticular zone, whereas in domesticated animals the same photoperiod increased the activity in the fascicular zone. It is suggested that selection of silver foxes for the domestication type of behaviour affects the sensitivity of the adrenals to external illumination. |