An important historical fact concerning these nomadic Negrito foragers is that they have not lived isolated from, nor independently of, other peoples, as was assumed and taught until the 1980s. Recent research has established that the Agta peoples have carried on intense symbiotic interaction with farming peoples not only for centuries, but for millennia. The ancestors of today's Agta, and of all Philippine Negritos, are assumed to be the aboriginals of that archipelago, having migrated into those islands 20,000 to 30,000 years ago. Much later, around 3000 B.C. , Austronesian-speaking peoples began migrating into the Philippines, probably from Taiwan. Gradually the Negritos switched from their isolated and independent hunting and gathering lifestyle as they increasingly developed symbiotic relationships with Austronesian farmers. For most Agta groups, this switch occurred by around 1000 B.C. From this time on, Agta traded and interacted heavily with farming populations. The more recent twentieth-century history of the Agta is another story. After thousands of years of living a relatively stable and adaptive life in the rain forest, they are today undergoing severe deculturation; their forest is being cut back, immigrants are depleting their game and fish resources, they are being herded onto small reservations by the government, and change is being imposed on them by various development agencies.