(Portland, OR) -- An Oregon Zoo polar bear is helping to test tracking equipment that can be used on wild polar bears. 3M is working with Polar Bears International to design tracking equipment that clips on fur instead of being a collar around the bear's neck. Collars don't work on male polar bears, because their neck is as wide as their head and the collar falls off. The zoo's polar bear, Nora, has tested a device they call "Burr on Fur." The device is made to eventually fall off, but it only lasted several days on Nora. Researchers are working on different ways to attach the device. It's difficult to observe polar bears in the wild because they live in one of the harshest environments on the planet.