The core culture or Pengngan Chamorro is based on complex social protocol centered upon respect:From sniffing over the hands of the elders (called mangnginge in Chamorro), the passing down of legends, chants, and courtship rituals, to a person asking for permission from spiritual ancestors before entering a jungle or ancient battle grounds. Other practices predating Spanish conquest include galaide' canoe-making, making of the belembaotuyan (a string musical instrument made from a gourd), fashioning of åcho' atupat slings and slingstones, tool manufacture, Måtan Guma' burial rituals, and preparation of herbal medicines by Suruhanu.Master craftsmen and women specialize in weavings, including plaited work (niyok - and åkgak -leaf baskets, mats, bags, hats, and food containments), loom -woven material (kalachucha-hibiscus and banana fiber skirts, belts and burial shrouds), and body ornamentation (bead and shell necklaces, bracelets, earrings, belts and combs made from tortoise shells) and Spondylus. The cosmopolitan nature of modern Guam poses challenges for Chamorros struggling to preserve their culture and identity amidst forces of acculturation. The increasing numbers of Chamorros, especially Chamorro youth, relocating to the U.S. Mainland has further complicated both definition and preservation of Chamorro identity. ] While only a few masters exist to continue traditional art forms, the resurgence of interest among the Chamorros to preserve the language and culture has resulted in a growing number of young Chamorros who seek to continue the ancient ways of the Chamorro people.