Hearing and Smell

Hearing
The domestic cat’s hearing is most acute in the range of 500 Hz to 32 kHz.[77] It can detect an extremely broad range of frequencies ranging from 55 Hz to 79,000 Hz. It can hear a range of 10.5 octaves, while humans and dogs can hear ranges of about 9 octaves.[78][79] Its hearing sensitivity is enhanced by its large movable outer ears, the pinnae, which amplify sounds and help detect the location of a noise. It can detect ultrasound, which enables it to detect ultrasonic calls made by rodent prey.[80][81]

Smell
Cats have an acute sense of smell, due in part to their well-developed olfactory bulb and a large surface of olfactory mucosa, about 5.8 square centimetres (29⁄32 square inch) in area, which is about twice that of humans.[82] Cats and many other animals have a Jacobson’s organ in their mouths that is used in the behavioral process of flehmening. It allows them to sense certain aromas in a way that humans cannot. Cats are sensitive to pheromones such as 3-mercapto-3-methylbutan-1-ol,[83] which they use to communicate through urine spraying and marking with scent glands.[84] Many cats also respond strongly to plants that contain nepetalactone, especially catnip, as they can detect that substance at less than one part per billion.[85] About 70–80% of cats are affected by nepetalactone.[86] This response is also produced by other plants, such as silver vine (Actinidia polygama) and the herb valerian; it may be caused by the smell of these plants mimicking a pheromone and stimulating cats’ social or sexual behaviors.[87]