What a surprise this must have been. Video has been released of a hunter in Idaho who was trying to use his elk call to call - you guessed it - elk. The good news is he did attract animals. The bad news is it wasn't elk.

According to this video, the elk call attracted a huge grizzly that came to within 16 yards of their location. At about the :40 second mark, the hunters realize the grizzly is about to get too close for comfort, so they begin making noises to make their presence known. Fortunately for them, the bear decided to head the opposite direction.

It's obvious these hunters knew what they were doing. Still, it's good to know what to watch for if you end up in the same situation. The Forest Service has great tips on what a bear will do when it's becoming aggressive.

On four legs, a bear may show agitation by swaying its head from side to side, making huffing noises and clacking its teeth.

A charge or retreat may follow. Flattened ears and raised hair on the back of the neck indicate aggressive intent.If a bear runs with a stiff, bouncing gait, it may be a false charge.

If I'm close enough to be able to see whether the bear's back hair is standing up, I'm too close and a change of underwear will definitely be in order.