About 100 years before the Spanish invasion, the Taínos were challenged by an invading South American tribe - the Caribs [Glos.]. Fierce, warlike, sadistic, and adept at using poison-tipped arrows, they raided Taíno settlements for slaves (especially females) and bodies for the completion of their rites of cannibalism. Some ethnologists argue that the preeminence of the Taínos, shaken by the attacks of the Caribs, was already jeopardized by the time of the Spanish occupation. In fact, it was Caribs who fought the most effectively against the Europeans, their behavior probably led the Europeans to unfairly attribute warlike tendencies to all of the island's tribes. A dynamic tension between the Taínos and the Caribs certainly existed when the Christopher Columbus landed on Puerto Rico.