After sniffing a spot where another cougar has urinated, a mountain lion will display a lip-curling grimace known as a flehman. This allows them to use a sensory organ in the roof of their mouth to better "read" the scent. Male lions may use the flehman response when smelling a female lion's urine, to determine whether she is ready to mate.

A cougar's sense of smell is better than a human's, but not as good as a dog's. The cats depend more on vision and hearing when hunting and are able to follow the scent trail of deer. Smell may play a more important role in finding a mate. Cougars also seem to share the domestic cat's attraction to catnip.