A battle cry is a yell or chant taken up in battle, usually by members of the same military unit. These cries can serve many purposes, including inspiring those otherwise inclined to stay back, promoting a sense of esprit de corps, or even terrifing the enemy troops. One famous battle cry was the rebel yell, a call taken up by troops fighting on the side of the Confederacy during the American Civil War. In Japan, the kamikaze pilots battle cry was "Tora, Tora, Tora". For this pilots, such cry help them to have the courage to give their lives for the empire. In Spain, a very religious country, during the conquest of America they cry "Santiago", looking for holy protection from St James. The vikings used to scream random things and did animal sounds during battle to scare their enemies. The effect of warriors doing "animal" sounds and cutting themself was enough weapon against any soldier. Many native americans used animal sounds to scare and to communicate. Some Northamerican tribes are famous for imitate so well these sounds.