The same pattern is seen among horses and various other social ungulates: it is not until the young males start developing secondary sexual characteristics that the unrelated dominant males begin to harass them into leaving the group.

• 在马与其他社会有蹄类物种，也可以观察到同样的模式：年轻雄性一开始发育次要性徵，没有血缘关系的雄性老大哥就会骚扰牠们，想把牠们赶走。