Does Behaviour After Weaning Affect the Dominance Status of Adult Male Mice (Mus Domesticus)?

To investigate whether behaviour in the litter predicted later dominance status, male mice were observed whilst within their litters from three weeks old, and when paired with an unrelated male as an adult. We found that males that were dominant in their litter were not more likely to become dominant as an adult. The best predictor of adult dominance status was the relative scent marking rate when with littermates, males that marked more than their adult partner were more likely to become dominant. The high scent mark rate of dominant males may be the cause not the consequence of dominance, they scent mark at a higher rate before becoming dominant. It was also shown that there are strong family resemblances for scent mark rate, body weight and most urogenital gland weights. This indicates that scent mark rate and urogenital gland weights may be determined genetically, or partly determined by parental effects. As found in previous work the preputial gland was heavier in dominant males than subordinates. Furthermore, dominant males were lighter than subordinates at the end of the experiment indicating that there may be a cost to maintaining dominance.