D4K has a marvelous list of lesson plans provided by Idaho Fish and Game. Click here to access them.
Discovery Education has a series of lesson plans for older students. Some can be adapted for intermediate classes. Click here to find out more.
Here is an entire unit on Polar Bears from Polar Bears International.
The North American Bear Center has some great lesson plans too. Plus they have live cameras for you to sneak a peek at bears in their natural habitat. Check it out here.
See the Polar Bear at the San Diego Zoo by live cam.
Additional information on bears from the Washington Department of Fish and Wildlife here.