These different types of lighting create different gradients and colours of light giving an image more meaning and depth. The way the light is enables the image to be more interesting and direct to what you want for your shoot.
Zoo Portraits is a humorous photo series by Barcelona-based photographer Yago Partal that matches animal heads with human bodies. Partal amazingly matches animals to appropriate human bodies and even manages to match their personalities and styles.
Himalayan Honey Hunters of Nepal, Photography by Eric Valli. "High in the Himalayan foothills, fearless Gurung men risk their lives to harvest the massive nests of the world's largest honeybees." (Check out the other amazing photos on Eric Valli's site)