The Amazon rainforest has an extremely warm and humid climate with over 9 inches of rainfall annually and average temperatures of 79 degrees. It is home to over 2500 fish species, 1500 bird species, and 1800 butterfly species as well as big cats and mosquitoes. The largest rainforest in the world, it covers 2.5 million square miles and produces 20% of the world's oxygen. To survive in this environment, the body must adjust to the heat by sweating more to regulate temperature without breaking down proteins, consume more water due to the heat, and adapt to higher oxygen levels. Essential gear includes fully waterproof rain gear, insect repellent, sunscreen, and waterproof backpack.