Lions and spotted hyenas may be South Africa's apex predators, but to animal behaviorist Kevin Richardson, these fearsome carnivores are among his best friends. See how this relationship plays a key role in a groundbreaking project led by some of the world's top wildlife biologists: a series of remarkable experiments designed to measure both species' social intelligence. Observe the different ways lions and hyenas approach and solve problems, and how they rely on cooperation to succeed and survive in their natural environment. (Source: The Smithsonian Channel)