Secrets of the Penguins

Millions of years ago, a group of penguins left the ice, riding powerful currents and arriving in strange new lands. They reshaped traditions for deserts and tropics - and even to live among humans. Tested to the extreme, they became perhaps the smartest of all penguins. National Geographic Explorer Bertie Gregory discovers the penguins' problem-solving, "talking" and enduring search for new worlds.