Today, humans are the only species of hominin in the world. 50,000 years ago, however, we were not alone - our cousins, the Neanderthals and Denisovans, walked the Earth with us. Their legacy lives on in our genomes today. Razib and Spencer take us on a tour of how we became a few percent Neanderthal, including an interview with anthropologist John Hawks. (Part 2 of 2)