The first evidence of human habitation in Guatemala dates to 12,000 BC. Archeological evidence, such as obsidian arrowheads found in various parts of the country, suggests a human presence as early as 18,000 BC. There is archaeological proof that early Guatemalan settlers were hunter-gatherers. Pollen samples from Petén and the Pacific coast indicate that maize cultivation had been developed by the people by 3500 BC. Sites dating to 6500 BC have been found in the Quiché region in the Highlands, and Sipacate and Escuintla on the central Pacific coast.