Q: How do documentary film makers get their video footage?
A: As safely as possible, i.e., from far, far away.
Polar Bear: Spy on The Ice is broadcast on BBC One at 2000 GMT on Wednesday 29 December - or afterwards on BBC iPlayer. (link)
"Shot mainly using spy cameras, this film gets closer than ever before to the world's greatest land predator.
Icebergcam, Blizzardcam and Snowballcam are a new generation of covert devices on a mission to explore the Arctic islands of Svalbard in Norway. Backed up by Snowcam and Driftcam, these state-of-the-art camouflaged cameras reveal the extraordinary curiosity and intelligence of the polar bear." Read more about the program here.
Here's a clip from the program, (without the bears destroying the camera):