Well... Columbus is to say. He wrote down everything that happened. The closest neighboring tribe inhabited other islands. They launched poison arrows at anyone when they approached their island, and were generally competitors to the Arwarks. They were called the Caribs and the Arwarks started rumors that they were mean and are people. Another term for their tribe was...get ready... Cannibals. Turns out once Columbus and his men managed to actually meet them, it was found they were more industrious and civil than the Arwarks. We know this because members of Columbus's crew wrote as much in their journals. However, Columbus used rumors of eating people as an excuse to attempt to sell them as slaves to Spain. It didn't work because the Cannibals actually fought back and the Spanish decided to skip them over in favor of conquering the more docile Arwarks.