They said that because they had heard that someone had said that sometime about something, and it means "we will fight for ever and ever."
But they didn't! At the very first volley the berries stained their dainty frocks, and the girls fled, screaming angrily:
"You horrid things! You've ruined our frocks!"
And the boys grinning delightedly, and rolling their black eyes, thumped their little brown heels on the ground, and beat their little bare, brown knees and chanted all together:
"Akarana Mototapu Rangitoto Ra!"
And of course you all know what that means! You don't? Well, I'm not quite sure myself, because I couldn't find it in the dictionary (so careless of Mr. Webster!) but it really doesn't matter.