Changed the batteries and memory card in one of my camera traps in the Big Woods earlier this week. Previously I had put some beaver castoreum on a short piece of a dead branch lying in front of the camera.
Castoreum is produced by beaver’s anal scent glands and is used by the animals to mark their territory. Castoreum smells somewhat like vanilla extract, but much stronger and not particularly pleasant; it's been used in perfumes and colognes, particularly ones that have a leather-like aroma. Castoreum has also been used as a food flavoring and, in previous centuries, in medicines. As an attractant for furbearers castoreum is the lure of choice for many trappers, so I’ve recently begun using it in front of some of my camera traps.
One camera trap, which seems to always have something interesting on the card, had quite a few photos of a good sized male bear that stopped to smell the castoreum. The bear didn’t just stop to take a whiff – first it walked up to the camera and examined it closely, having its picture taken five times. It then turned and walked back to the piece of dead limb with the castoreum – smelled the castoreum, then lay down on the dead branch, got up and lay down again, and finally it apparently rubbed against the stick as a dog would rub and roll on something with a strong odor.
From the first photo to the last, he spent eight minutes in front of the camera.