5. Monkeys and the Polio Vaccine
Monkeys were vital to the battle against polio. Their similar immune systems allowed researchers to observe how the polio virus attacked the body and to test early vaccine candidates for safety and effectiveness. These crucial studies led to the development of the first successful polio vaccines, which have since helped eliminate the disease from most parts of the world. The global decline of polio stands as a testament to the pivotal role monkeys played in transforming public health. Learn more from Smithsonian Magazine