Episode 5: March of the beaver. The desolate Alaskan tundra—a landscape that has literally been frozen solid for thousands of years—is suddenly caving in on itself.

When National Geographic caught up with Goldfarb by phone in New York, he explained how beavers are playing a crucial role in the American West, how a beaver named Jose set up home on the ...

Castoreum, a substance from sacs near a beaver’s anus, has been used in human products for more than 2,000 years. Some wonder if it's still an ingredient on today's grocery shelves.

The largest beaver dam on record is in Wood Buffalo National Park in Canada, stretching the length of seven football fields. The dam is so big, it can be seen from space.

Castoreum, a substance from sacs near a beaver’s anus, has been used in human products for more than 2,000 years. Some wonder if it's still an ingredient on today's grocery shelves.

Despite internet claims, castoreum—a substance found in beaver glands—is rarely used today as a food flavoring. ... a U.K.-based beaver conservation organization, tells National Geographic.