Remains of tubers that are identified as probably ube (Dioscorea alata) have been recovered from the Ille Cave of Palawan (c. 11,000 BP). This also serves as evidence that ube is native to Island Southeast Asia and evidence that humans from that period already knew to exploit starchy plants. Ube also appears in archaeological records in the Batanes Islands by about 3,500 years ago, associated with some of the earliest farming communities in the region. Among the yam species that were cultivated independently within Island Southeast Asia and New Guinea, ube and lesser yams were the only ones regularly cultivated and eaten because the other species were usually considered as famine food due to their higher levels of the toxin dioscorine which requires that they be prepared correctly before consumption.