Did you know that in the United Kingdom, Botts’ dots are even called cats eyes, because of how they mimic the appearance of a cat’s eyes at night?
Their bright, iridescent glow is so distinctive, it’s easy to assume that cats must be able to see clearly in the dark too.
But how much truth is there in that? Do cats have night vision? Let’s find out.
Understanding cat vision
It is impossible to explain how cat vision compares to human sight without first quickly describing the anatomy of the eyeball.
So let’s sit back and absorb a short (and sweet) biology lesson!
In both cats and humans the eyeball is a sphere, filled with clear gel. The inside surface of the back of the sphere is called the retina, and the retina is made up of rod cells and cone cells.
These rod and cone cells are the highly sensitive to the light which enters our eyes, and turn it into a picture for our brains.
Rod cells help us to see in poor light
Rod cells are especially sensitive to low levels of light.
We use them to distinguish outlines in gloomy conditions, and to differentiate between shades of gray.
Cone cells help us to see in bright light
Cone cells are more sensitive in bright conditions, and we use them to see color and focus on complex shapes.
Remember this for later: we’ll come back to it.
How cats eyes and human eyes differ
Cats and humans have very different proportions of rod cells and cone cells, and that’s what makes a big difference to our vision.
Cats’ eyes have six to eight times more rod cells than human eyes, which means they can see in black and white at much lower light levels than us humans.
They also have a phenomenal ability to dilate the pupils of their eyes, almost until the entire visible surface of the eye appears black.
This allows the maximum amount of light possible to enter the eye and trigger signals from those rod cells.
Tapetum lucidum
There’s another clever trick going on inside cats’ eyes too.
It might sound like a spell from the Harry Potter series, but in fact the tapetum lucidum is a thin layer of reflective tissue which lies behind the retina.
The words tapetum lucidum are Latin, and mean “bright tapestry”.
After light has passed through the retina, the tapetum lucidum reflects it back through the retina a second time, giving the rod cells another chance to take on information.
This gives cats another big advantage when seeing in low light conditions.
By the way, the tapetum lucidum is what gives your pet’s eyes a bright appearance when you take their photo with a flash.
And the color of the tapetum lucidum as it appears in photos is as unique your cat as the color of it’s irises!
So what’s the answer: can cats see in the dark?
Cats have some highly specific adaptations within their eyes to enhance their vision in low light conditions.
But their sight still depends upon receiving light into the eye, so they can’t see in total darkness.
However, they can make out gray scale outlines in light levels six or seven times lower than we can.
Indeed, since the invention of street lights, security lights, and illuminated advertizing, there can be few places these days where domestic cats are truly unable to see.
Can kittens see in the dark?
Kittens have all the same adaptations as adult cats to see in low light, but like human babies, their eyesight generally is poor to begin with.
From the time a kitten first opens it’s eyes at around nine to fourteen days, it will take about ten weeks for their vision to become clear and focused.
Don’t expect too much of their vision at day or night until then.
Do cats see in color?
Did you remember that earlier I said the cone cells in our eyes are responsible for detecting color?
Before we end this article let’s ask one more question: can cats see color?
For a long time people (including experts!) have believed that cats can only see in black and white.
To accommodate a large number of rod cells in their retinas, cats have had to compromise on the number of cone cells they have instead.
In fact, they have ten times fewer cone cells than humans.
Whilst cats have very few of the specialized cone cells needed for perceiving color, recently veterinarians have come to believe that cats do have some limited color vision.
However, the shortage of cone cells means that cats’ color vision is not as bright or detailed as ours.
What colors can cats see?
It seems that cats are better able to distinguish colors at the blue end of the spectrum, such as blues, purples and violets.
They are less likely to be able to distinguish between reds, yellows and greens at the other end of the spectrum.
Cat’s eyes and ultraviolet
In 2014, Professor Ron Douglas and Professor Glen Jeffery in the United Kingdom found fascinating evidence that cats might also be able to see in ultraviolet.
This isn’t uncommon in other animals, and serves all kinds of purposes for survival and communication.
But we don’t know yet if or how cats use this ability in any special way.
Conclusion
Cats do not have perfect night vision, and they cannot see in total darkness. But they do have remarkable adaptations which allow them to see in much lower light conditions than you or me.
These adaptations allowed their ancestors to hunt nocturnal prey at dawn and dusk.
However to achieve these advantages in low light, the trade-off has been a reduction in color vision.
What about your cats? Do they prefer to hunt after dark and put their remarkable eyesight to good use?
Or have you noticed them being able to distinguish between different colors? If so, we’d love to hear about it in the comments section below!
“Today’s article is by Sarah Holloway. Sarah holds a bachelors degree in Zoology and has a special interest in animal behavior and communication”
References
- “How cats see the world”, (2013), Business Insider Science.
- Meyer, D.R. et al, (1954), “Absence of color vision in cat”, Journal of Neurophysiology, Vol 17, 289-293.
- H. Douglas, G. Jeffery, (2014), “The spectral transmission of ocular media suggests ultraviolet sensitivity is widespread among mammals”, Proceedings of the Royal Society, Vol 281, Issue 7180.
- Weale, Robert Alexander. “The spectral reflectivity of the cat’s tapetum measured in situ.” The Journal of physiology 119, no. 1 (1953): 30-42.
- Kuffler, S. W., R. Fitzhugh, and H. B. Barlow. “Maintained activity in the cat’s retina in light and darkness.” The Journal of general physiology 40, no. 5 (1957): 683-702.
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