S1, E2: Equipped with 3-inch long canines and retractable claws like switchblades, big cats are among the fiercest and most fascinating four legged beasts on the planet - capable of taking down fleet footed antelope, two - ton elephants and even human beings. National Geographic treks through the African grassland and the swamps of India to track and study the ultimate engineering and stealth ambush tactics of lions, tigers and leopards.