Although cats’ eyes appear to glow in the dark, they are actually reflecting ambient light due to a reflective surface behind their retinas called the tapetum lucidum. Flash photography, car headlights, and any other available light may create the glowing effect.
The tapetum lucidum enhances a cat’s night vision by bouncing light back so that the photoreceptors in the eye have a second opportunity to use it if it didn’t hit them the first time. This enables a cat to see in dimmer light than humans can.
Humans, some other primates, squirrels, pigs, and kangaroos don’t have the tapetum lucidum, but many other animals do, including dogs, horses, deer, cattle,and ferrets. However, humans may appear to have glowing eyes at night if they have cataracts, which can create a white reflection, and via the “red-eye” effect in flash photography.
Animals with a tapetum lucidum may reflect different colours of light due to varying retina pigmentation, age, minerals such as zinc or riboflavin in the tapeum lucidum, and other factors.
Do cats dream?
Cats enter a sleep state called rapid eye movement (REM) just like people do, and this is the sleep phase during which the majority of dream activity occurs.
Those who have watched sleeping cats will have noticed that they sometimes engage in certain movement sequences that appear to mimic waking activities such as running or tackling. A sleeping cat may twitch her whiskers, flick her ears, move her paws, and even make sounds.
The purpose of dreaming is not known for sure, though there are some intriguing theories. However, it does seem that REM sleep is important. Like people, cats that are deprived of REM sleep are more aggressive. Studies of REM-deprived cats have also found an increase in eating and grooming behaviours. These findings are interesting, given that people are more likely to overeat if they don’t get sufficient sleep, and overgrooming in cats can be a sign of anxiety.
How many hours do cats sleep each day?
Adult cats spend approximately 65% of their time sleeping, or nearly 16 hours per day, though it’s mostly a light sleep. Only 15% of their time is spent in deep sleep. Kittens, by contrast, alternate between deep sleep and being fully awake, dividing their time equally between these two states for the first few days of life, after which they gradually evolve the adult cat sleep pattern.
Why cats and people need to sleep is unknown, but sleep deprivation over the long term can be fatal, so it’s obviously important to get enough sleep. Theories that have been advanced to explain the need for sleep include:
- Energy conservation
- Tissue repair
- Flushing out toxins from the brain (which reduces the risk of neurodegenerative diseases such as Alzheimer’s)
- Recharging neurotransmitter supplies
- Learning and forming memories
There is some scientific support for the memory-forming hypothesis. Researchers have found that kittens exposed to visual stimulation during the critical period for visual development form far more brain connections during sleep than kittens that are kept awake after visual stimulation. In fact, even if they’re exposed to more hours of visual stimulation, the sleep-deprived kittens don’t form as many brain connections as those allowed to sleep after the first session of visual stimulation.
Is a cat’s sense of taste better or worse than that of a human?
Cats have a weaker sense of taste than people. A human has approximately 9,000 taste buds, compared to 473 for a cat.
How much better is a cat’s sense of smell than that of a human?
Cats rely on their sense of smell more than any other. While a cat’s visual acuity is 10 times lower than that of a person, she has 200 million odour-sensitive cells in her nose compared to a human’s paltry 5 million.
The cat’s well-developed sense of smell ensures that scents play a significant role in feline social communication. Rubbing their bodies on things, scratching objects, and spraying all leave scent messages for other cats.
Cats even have an organ in the roofs of their mouths called the vomeronasal organ that enables them to gather additional information about scents, which may help with finding fertile mates and suitable prey. When a cat appears to be grimacing with her mouth open as though she has encountered a disgusting smell, she is actually engaging in the Flehmen response, which directs scent molecules toward the vomeronasal organ.
How powerful is a cat’s hearing?
Cats’ ears are controlled by approximately 30 muscles and they are able to rotate their ears 180 degrees to catch various sounds. A cat can hear many high-frequency sounds that humans (and even dogs) can’t, and is better able to distinguish tone and pitch.
Cats have superior sound location abilities. If a cat is a several feet away from multiple sound sources that are only 3 inches apart, she can locate each of the sources individually.
Although both humans and cats can hear sounds as low as 20 Hz, a human’s ability to perceive sound stops at frequencies above 20,000 Hz, whereas dogs can hear frequencies up to 45,000 Hz, cats 64,000 Hz, and mice 95,000 Hz.
How fast can a cat run?
In contrast to dogs, which tend to run slower but have more endurance, cats are built for brief, intense sprints.
The fastest domestic cats can reach speeds of 30 miles (48 km) per hour. Lions have been clocked at 48-59 miles (77-95 km) per hour, but cannot go far at this speed before tiring.
Cheetahs, one of the fastest mammals on land, can run up to an estimated 65 miles (105 km) per hour. Impressively, cheetahs can accelerate from a standstill to 48 miles (77 km) per hour in 2 seconds.
Which animals hunt cats?
Coyotes frequently hunt bobcats and domestic cats (and smaller dogs) if they can get them. Wolves have been known to kill pumas and sometimes they kill domestic cats as well. Domestic cats are also attacked occasionally by raccoons, foxes, owls, eagles, and hawks (though the avian predators are more likely to go for kittens than large adult cats).
Some dogs (especially those of particular breeds such as Weimaraners) may hunt cats if they haven’t been socialized with them from a young age. However, despite their reputation as natural enemies, cats and dogs can learn to get along well, particularly if they are raised together. Some cats and dogs even become the best of friends.
It’s also possible, though trickier, to encourage friendships among adult cats and dogs. In this case, the key to success is controlling the dog and letting the cat take charge of the situation at her own pace, as she will be the more fearful of the two, given the size difference (the exception to this is introducing a large cat to a very small dog).
For more cat articles, see the main Cats page.
- Cats International. (2007). “The Cat’s Sense of Taste” and “The Amazing Sense of Smell.” CatsInternational.org.
- Schelling, C., Dr. (2005). “A Cat Is Listening.” CatHealth.com.
- Schneck, M., & Caravan, J. (1990). Cat Facts. New York: Barnes & Noble Inc.
- Seidensticker, J., & Lumpkin, S. (2006). Cats: Smithsonian Q&A: The Ultimate Question and Answer Book. Washington, DC: Smithsonian Books.
- Stoica, T. (2019). “Why Do We Sleep?” Scientific American (Blogs), January 25, Blogs.ScientificAmerican.com.
- Vogel, G.W. (1976). “Archives of General Psychiatry. XXXII, 1975: A Review of REM Sleep Deprivation.” Psychoanal Q., 45:339, pp. 749-761.