Discovery

• The first European to traverse the Amazon rainforest was Spanish explorer Francisco de Orellana, who was a part of Francisco Pizzaro's army. In December 1541, Orellana's ship got separated from the rest of the fleet during an expedition to the interior of South America. It is believed that the Amazon was named so because of attacks along the river by fierce female warriors like the mythological Amazons.
  
  

Early History

• The Amazon was formed during the Eocene era after temperatures had dropped around the world as the Atlantic Ocean had widened, paving the way for a warm and wet climate. The Amazon forest is at least 55 million years old. After the extinction of the dinosaurs, the climate got even wetter and the rainforest grew as far south as the 45-degree latitude. The last glacial maximum (LGM) was a threat to the Amazon, but it survived.
  
  

Since the LGM

• During the Mid-Eocene era, the drainage basin of the Amazon was divided into two parts by the Purus Arch; the water on the eastern side drained into the Atlantic and the western side into the Pacific. However, the Amazon we know today does not drain like this. The Andes rose, forming a huge lake. As time progressed, the lake could not hold the water and it broke through the Purus Arch, draining into the Atlantic.
  
  

Effects of the LGM

• Significant changes were made to the Amazon rainforest during the LGM, which lasted for 21,000 years. The size of the rainforest and the rainfall both reduced drastically. Some even claim the rainforest was a very small and isolated region of moist vegetation separated by grasslands. Vegetation and animal life went through some drastic changes as well.
  
  

Human Settlement

• There has been evidence of human settlement in the Amazon for a long time. Careful study of this evidence provides us with clues as to when the human race settled down in the Amazon. Excavations in Caverna da Pedra Pintada prove that humans arrived in the Amazon Basin at least 11,200 years ago. Settlements in the periphery of the forest began by around 1250 CE. The main source of food was by hunting.