Extras
Uncover the secret world of New York and London’s resilient pigeon flocks.
Who rules the streets -- and skies -- of the city?
A mother mountain lion risks her life to feed her six kittens.
Mountain lions risk everything to hunt elk, prey more than twice their size.
Follow a female mountain lion in the Montana mountains over the course of a decade.
Discover how rapidly declining sea ice is reshaping the future for walruses.
An orphaned baby walrus, just a week old, gets a second chance.
See how the Arctic’s most enigmatic animals are coping as the sea ice melts.
It was once believed that walruses dug for clams with their tusks, but the truth is even stranger.