Dogs:
* More olfactory receptors: Dogs have about 300 million olfactory receptors, compared to 20 million in humans and 14 million in cats.
* Larger olfactory bulbs: This part of the brain processes scent information and is significantly larger in dogs.
* Excellent at tracking: Dogs are masters of scent detection and can track individual scents for long distances.
* Strong sense of smell: They can smell things humans can't, like subtle changes in scent indicating disease or danger.
Cats:
* Highly sensitive to pheromones: Cats use their sense of smell for communication, territory marking, and social interactions.
* Excellent at detecting subtle smells: They are sensitive to specific scents like prey, catnip, and specific individuals.
* Can smell things at greater distances: Cats can smell things up to 6 times further away than humans.
So, who wins?
It depends on what you consider "keener." If you're talking about quantity of scent receptors and overall sensitivity, dogs win.
But if you're looking at detection of specific scents and subtle variations, cats have their strengths.
Ultimately, both dogs and cats have incredibly sensitive noses, each uniquely adapted to their needs and hunting styles.