Jangmo-o clang their scales constantly, for they know they are not yet the equals of many pokemon, but when they evolve, they grow lonely and look for challenges. Hakamo-o are not as consistently loud as Jangmo-o, for they wish to test their strength, not to deter opponents long before their battles begin. And yet the dances with which the Hakamo-o begin their battles are, if moderately quieter, still more frightening than a Jangmo-o's constant clang.
Alolans have long known to be wary when the noise stops from a Jangmo-o's valley; although theoretically it could reflect an untimely death, it far more commonly signals the inhabitant's evolution. And while Jangmo-o are content to remain cloistered, Hakamo-o wish to test their strength. This test is far more difficult to find than one might think, for given their reputation, only the bravest humans and pokemon in town will dare to meet one. Many who think they have the courage to fight a Hakamo-o will run away before the first blow is struck, scared off by the loud stomps and cries of their famous war dances. Those who remain face a pumped-up opponent, faster and stronger than one who enters a battle without the opportunity to dance.
Interestingly, the war dance invented by the Hakamo-o has spread much further than its progenitor, among humans and pokemon alike. Alola has historic cultural and trade links to islands across the Pacific, and the Hakamo-o dance (or "haka" for short) has been long performed before battles and sporting events by people who have never seen a Hakamo-o. And many dragon pokemon have also learned from the customs of the Hakomo-o, borrowing their dances to grow even stronger than the castle-wrecking Salamence so omnipresent in medieval history.