35,000 walruses on Alaska shore a sign of tremendous change

Walruses are one of many animals who need Arctic sea ice. But when that ice melts, they must to go ashore to rest and find food. In Alaska, 35,000 walruses have been observed on one beach. Judy Woodruff speaks with Margaret Williams of the World Wildlife Fund about the consequences of disappearing ice for animals and how humans are connected to the story.