We’re not talking about lying under the sun in the hopes of roasting your skin. The Native Americans developed tanning methods for leather, which people still use today. They typically used fatty animal tissues like the brain, liver, and fat to tan the hides. Sometimes, they even kept the fur for decorative purposes. They would even go so far as to soak the skin in a solution of the animal’s brain, and then roast the skin over a fire (Sky Above Us).