How Your Senior Cat Sees, Hears And Smells

Find out how your senior cat perceives the world using his senses of sight, hearing and smell, and what problems might occur in his old age.

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The sense of smell is very important for cats. afqphoto/iStock/Thinkstock
Dr. Brian Roberts

Those of us who love cats likely have had a senior, older kitty at some point in our lives. Senior cats are those in the final quarter of their expected lifespan. For most cats, that’s around 10 to 12 years of age and up.

You may have noticed your senior cat’s senses are not as sharp as they used to be. Cats may have heightened senses, but similar to humans, their vision, audition and olfaction (seeing, hearing and smelling) can diminish with age. Read on to learn how cats’ senses differ from ours and what types of problems your senior cat might encounter.

How Cats See
Visually, cats have adapted to finding prey in low light and at night. This built-in “night vision” is due to a special layer of reflective cells called the tapetum. The tapetum cell layer allows more light to reflect back onto the retina. Cats’ larger visual field also helps with hunting.

While their vision has its advantages, cats’ visual acuity is not too good. Perfect vision or “20/20” for us is more like 20/40 in cats, meaning an object we can identify at a distance of 100 feet would be identified by your cat at 20 feet away.

Also, cats are much better at tracking moving objects versus static ones. Have you ever been playing with your cat by throwing a little ball or toy mouse? When the object is in motion, your cat is keen to follow it, but if your cat wasn’t paying attention during the throw, he has a harder time finding the ball when it’s not moving.

You also may have heard that cats are color-blind and only see in black and white. Well, that’s not entirely accurate. Cats can see some colors, just not as many as humans can. Their color palate is limited to yellows, blues, indigo and grey.

Vision Problems In Senior Cats
So, what are some visual issues to watch for in your senior cat?

A common disorder that affects senior cats is called iris atrophy. The iris, which is the colored portion of the eye around the pupil, will degenerate or atrophy with age. This causes the color to become dull, and you’ll also see “black holes” or streaks where color used to be. Luckily, it rarely affects vision, but for cat lovers unfamiliar with it, it looks serious!

Another common disorder of senior cats that affects the eyes is hypertension or high blood pressure. This occurs typically with kidney disease, which is very common in senior cats. When the kidneys don’t function properly, they try to protect themselves by releasing hormones, like rennin, to increase blood pressure. As the kidney dysfunction progresses, the hypertension becomes worse. One of the first organs affected by hypertension in cats are the eyes. The high blood pressure causes damage to the retina, leading to blindness.

Other disorders which cause hypertension in cats include hyperthyroidism and heart disease. Hyperthyroidism is a disorder caused by excessive production of thyroid hormone by the thyroid glands. Thyroxine, the hormone, controls metabolism, and when too much is being produced, the body’s metabolism goes into overdrive. One consequence is hypertension.

Unfortunately, blindness from retinal bleeding or detachment is sometimes the first indication that there’s a blood pressure issue. I would recommend that all senior cats, especially those with a history of kidney dysfunction, get a blood pressure measurement during a visit to the vet.

How Cats Hear
Cats have the ability to hear sounds we humans cannot. They can hear noise in the ultrasonic range of frequencies. Similar to “night vision,” this is another adaptation to locate prey. Most rodents make very high-pitched squeaks, and cats can hear and locate them.

Hearing Problems In Senior Cats
Like people, senior cats can develop age-related hearing loss, but it’s very uncommon. Ear infections are also pretty uncommon in cats. However, senior cats with white fur or light-colored coats are prone to skin cancer, affecting the ears. Cats who enjoy sun-basking are at most risk.

The most sun-induced cancer is called squamous cell carcinoma. If lesions develop, they are typically raised, hairless, red to black growths that look like discolored warts. Treatment is surgery, usually necessitating removal of the external ear pinnae. This doesn’t affect the ability to hear, but is cosmetically unpleasing for certain. So, if you have a white cat who likes to sunbathe in the windowsill, put some sun-block on the outside of their ears. Check with your veterinarian regarding the ingredients to make sure it’s safe. Cats will groom their ears with their paws and then lick their paws afterwards.

How Cats Smell
The most developed sense — that of smell — is really important for cats. Cats have a larger portion of their brain dedicated to smell than humans do. They also have a secondary olfactory organ, called the vomeronasal gland, which is used to detect and interpret pheromones. Pheromones among cats are like Facebook for people. They tell a story of what other cats are around, whether they are males or females, and if they are in heat.

Olfactory Problems In Senior Cats
Similar to other aging organs, as time goes on, the ability to smell may diminish as part of the aging process. During aging, nerve cells, muscle cells and glandular cells are less efficient at removing built-up toxins, and suffer oxidative stress. Oxidation leads to genes being turned on which can program the cell to stop working or to die, called apoptosis.

The big problem for senior cats who cannot smell well is that of nutrition. Cats who cannot smell will not eat well. So, if you notice that your senior isn’t that interested in the cat food you’ve been providing, try another one that has a stronger odor. You can also try to heat up wet food to vaporize more aroma. However, I strongly recommend that any senior cat who is not eating well pay a visit to your family veterinarian. Many age-related disorders can affect appetite besides just losing some ability to smell.

Article Categories:
Behavior and Training · Cats