A massive pack of 25 timberwolves hunting bison on the Arctic circle in northern Canada. In mid-winter in Wood Buffalo National Park temperatures hover around -40C. The wolf pack, led by the alpha female, travel single-file through the deep snow to save energy. The size of the pack is a sign of how rich their prey base is during winter when the bison are more restricted by poor feeding and deep snow. The wolf packs in this National Park are the only wolves in the world that specialise in hunting bison ten times their size. They have grown to be the largest and most powerful wolves on earth

Last week a remarkable picture of 25 wolves walking single file made the rounds via e-mail and facebook. The text of the e-mail I received said the picture was taken near Weippe. Now there are certainly wolves near Weippe but I'm skeptical there are any packs with 25 members.

One thing I've learned while covering the reintroduction of wolves to Idaho is to never say never. But I've also learned you can't trust random photos and the accompanying text that pop into your inbox. So I did some poking around and I believe the picture was taken in the Canadian Arctic by biologist Chadden Hunter while working on the televison program "Frozen Planet."

The show is currently being aired by BBC 1 in Europe and will be shown in North America by the Discovery Channel early next year. I viewed some clips and it looks to be a wonderful program. If you are interested in wolves and what they can do, check out a clip of a pack hunting bison.

You can view more clips and learn about Frozen Planet here, or visit Chadden Hunter's blog here and if you would like to see how many timesHunter's image has been used on the internet follow this link.