The ursine nose is lined with a vast sheet of specialized tissue, called the epithelium, which is embedded with scent-detecting nerves. Like the human epithelium, these cells have the exceptional ability to regenerate themselves (unlike most other nerves). But a bear's epithelium dwarfs our own. "It is much, much larger than a human's," explained Heiko Jansen, a neuroscientist who researches human and animal physiology at Washington State University. "It's several orders of magnitude larger."
— Read more at What would it be like to smell the world like a bear? at Mashable.