Senses are so important for we humans to function; it’s not surprising that cat owners have questions about how their pets perceive the world around them. Good news for all you curious cat owners out there: There actually has been quite a bit of research regarding cats’ vision, hearing and sense of smell.
How Your Adult Cat Sees
Many of us have the impression that our adult feline friends have extraordinary vision. And they do, in many cases.
Ever notice when it’s dark and the light reflects a bright yellow/green from your cat’s eyes? This “eye shine” is due to a reflective layer of cells along the retina or the nervous tissue that increases the amount of ambient light detected by photoreceptors. It’s like built-in night vision, and it helps cats hunt their prey.
Cats also have a wider field of view than humans (200 degrees versus 140 degrees), and excel at tracking moving objects.
However, while feline vision has adapted to notice moving objects very well and see them in low light, their visual acuity (clarity or sharpness of vision) is not as good as ours. For example, objects we can see in detail at 100 feet away can only be seen by cats at about 20 feet away.
Also, cats don’t have the ability to see as many colors as humans do. While they don’t see the world in black and white, their color vision is limited to blues, grays and pale yellow.
So basically, vision in cats has developed to find and track fast moving objects in low light, but not define what that object is from a distance or from close up. Luckily, they don’t need to read or drive a car!
When your veterinarian performs a physical exam, one of the things we assess is the eyes. Our test for vision is pretty rudimentary. In veterinary terms, it’s called a menace response. We make a fist and “knock” near their eye, determining if they see the threat and blink. Another way we can check for vision is to drop or throw cotton balls and see if your cat will track them falling. Veterinary ophthalmologists (yes, there are veterinarians who specialize in diseases of the eye) may even set up a maze to see if your cat can navigate it. Another thing that a cat owner may notice, or actually not notice, is a lot of tearing. Cats normally do not produce many tears, but when tearing is excessive, it’s usually a sign of a problem like an infection or an ulcer of the cornea.
How Your Adult Cat Hears
The sense of hearing, or audition, is highly developed in cats. They can hear a much larger range of sounds than we can. Cats can hear sound in the ultrasonic range (>25,000 Hz). Small prey like mice and rats use very high-pitched, ultrasonic sounds when calling each other. Luckily for our furry friends, they can not only hear these squeaks, but also locate them. The majority of cats have upright ears with many, many muscles that can rotate and bend them. This allows cats to determine the general direction of sounds they hear.
The inner structure of a cat’s ear is also different from our own. We have a horizontal ear canal that extends from the outer ear to the ear drum in a relatively straight line. Cats have both horizontal and vertical parts to their ear canal.
The most common ear disorder I diagnose in adult cats is ear mites. Unlike floppy-eared dogs, cats rarely get ear infections. When they do present for scratching and excessive discharge from the ears, it’s usually due to ear mites, known by the scientific name Otodectes cynotis. These tiny, eight-legged bugs are highly infectious to cats and are responsible for 50 percent or more of ear infections. Luckily, they are easy to diagnose and treat. Your vet will take a swab of the inside of the ear canal and examine the discharge under a microscope. The mites are easy to spot. Treatment is a simple injection or topical application of a drug repeated in three weeks, in coordination with the mite life cycle.
How Your Adult Cat Smells
Although cats have small noses, they have a large portion of their brain, called the olfactory bulb, dedicated to interpretation of scents and smells.
In addition to the nasal passages, cats also have an additional olfactory area called the vomeronasal organ. It’s a small patch of sensory tissue just behind their top front teeth on the hard palate. The vomeronasal organ’s primary role is detection of pheromones from other cats. You’ll notice that cats will greet each other by rubbing cheeks. Glands in the cheeks release pheromones. Those pheromones tell a story about the cat’s sex, other cats they have been in contact with and, for females, if they are in heat! Cats will rub their cheeks all around their territory, like our legs. It’s not just a sign of their affection for you but also to mark you as their “property!”
Most adult cats have had, and successfully overcome, an upper respiratory infection. These are common in kittens and are caused by viruses such as feline calcivirus and feline herpesvirus. Herpes viruses are species-specific and can be harbored by the host chronically. So, your adult cat may “get a cold” during stressful events like a new season or when your family visits for the holidays. It’s not that dangerous of a virus, rarely causing something like pneumonia, but it can lead to nasal discharge and sneezing.
The worst thing about respiratory infections is that they can cause cats to lose their sense of smell, just like when you or I get a head cold. When cats can’t smell, they rarely will eat! Luckily, there is a vaccine for this virus and there is treatment. Treatment will not eliminate the virus, but will help with the symptoms. However, cats who carry the virus may have “breakouts” of illness during stress or if they become ill with something else. When actively sick from Herpes, cats can shed the virus and infect other cats.