Complex sentence: According to Acoma oral traditions, the average Spaniard at the time weighed much more than the average Acoma, and the Spaniards also brought with them attack dogs, which were believed to be fed on human flesh and trained to eat humans alive.
Split into simpler sentences: According to Acoma oral traditions, the average Spaniard at the time weighed much more than the average Acoma. The Spaniards brought attack dogs with them, which were believed to be fed on human flesh and trained to eat humans alive.