Cat’s noses have around 40 times the number of scent-sensitive cells a human’s nose has. Cat's improved sense of smell is already impressive, but they have another odor detector that you might not know of. This second odor detector is called the Jacobson’s organ and is in a cat’s mouth. This odor detector not only detects smells like a cat’s nose, but it also allows a cat to more clearly decipher the smell than if they only used their nose. You can usually tell when a cat is using this odor detector because they might lift their head, open their mouth slightly, squint their eyes, and curl back their lips. Cats are not the only animals who can smell using this second odor detector. Some other animals who can use this include, llamas, rhinos, giraffes, and several other animals.