I just ran across a fairly interesting article about the power of bear noses. It really shines a new light on bear behavior. Here's a quote:

A run-of-the-mill dog's sense of smell is roughly 100 times greater than a human's. A good hound dog's nose is perhaps 300 times better.

But a bear's scent system, Stevenson said, is at least seven times better than the hounds.

“It's remarkable,” he said. “It's how they know the world.”

When humans think about their hometowns, they think in terms of visual maps - down this street to that avenue, turn left at the bank, right at the stoplight.
The whole story is in the Missoulian.