The tribes of Formosa were predominantly matrilineal. A village’s properties, lands and farms were often owned by the women, and lineage was traced down the mother’s line, with men marrying into womens’ families. Men and women lived separate lives, existing in separate worlds which only rarely intersected. The village square was the domain of the women, who cultivated the fields, gathered the crops, and did all the cooking, weaving and child-rearing. From the age of four onwards, boys left their mother's homes and spent much of their life living apart from women in communal ‘men’s houses’, where they spent most of their days training to be a hunter and a warrior.
To be a man among the natives of Formosa was to be deadly with the bow, arrow, and spear, their primary quarries being the Formosan sika deer, sambar deer and muntjac. Women were strangers to the world of hunting, and their intrusion within it was strictly taboo. Several days before departing on a hunt, all members of the expedition had to purge themselves of feminine residue. Sexual contact was strictly forbidden, and even touching women’s clothing was said to portend misfortune. Wildlife was not the only target of the Formosan hunter. Headhunting was practiced among every indigenous Taiwanese tribe, with young males required to kill an enemy and claim their head as a trophy in order to advance to full manhood. In many ways, the main day job of the indigenous Formosan man was headhunting and protecting his village’s women from rival headhunters. The role of the warrior was taken so seriously that among the Siraya and various other peoples, men were discouraged from marrying or having children until they were in their mid-thirties so they could spend the entirety of their athletic prime singularly focused on acquiring heads for the tribe. Headhunting was of crucial spiritual importance and was seen as vital to placate and receive blessings from the Gods. The Seediq people believed that only men who had hacked off the heads of their enemies would be able to cross the rainbow bridge into the spirit world upon death.