Both cats and dogs have very sensitive senses of smell, but dogs' sense of smell is far superior. A dog's sense of smell is thousands of times more sensitive than a human's, allowing it to distinguish a wide variety of odors and detect scents from 400-500 meters away. While cats also have a strong sense of smell, its sensitivity is generally considered to be over 100,000 times greater than a human's, though slightly less sensitive than a dog's.
This is mainly because dogs have many folds in their olfactory mucosa and a large number of olfactory cells, enabling them to capture more odor molecules. Cats, on the other hand, rely primarily on cribriform cells in their nasal mucosa. Overall, dogs have a slightly better sense of smell in terms of sensitivity and discrimination.
