Cat Vision: Seeing with Cat Eyes
By Dr. Carly I. O'Malley December 01, 2018
Animals use a lot of senses, such as sight, sound, and scent to navigate the world around them. For many animals, vision is an important sense that allows them to move around their environment skillfully, find and hunt food, and interact with members of their social group. An animal’s vision has been carefully honed over a long period of time and is specially adapted to the natural ecology of that animal (Banks et al., 2015).
Now that many animals, particularly our domesticated animals, are housed in more unnatural settings, it is important for caretakers to understand how an animal’s vision is structured so that we can try to see the word from their perspective. It is important for caretakers to understand that animals do not see the world in the same way we do, and this may lead to limitations in how they live in our human world.
Cats are skilled hunters who are primarily active at dawn, dusk, and night. Cats are also agile predators who like to perch up high and can swiftly jump and balance on different surfaces. They are also social animals that communicate in a variety of ways with members of their own species and with their human caretakers (Stella & Buffington, 2013). All of these species-typical behaviors rely on their vision to some extent and their vision is specially designed to assist them with all of these tasks. Learning about your cat’s vision can help you better understand their natural behavior as well as help you create an environment where your cat feels comfortable and safe.
How Do Kittens Develop Their Vision?
When kittens are first born, their eyelids are fused shut meaning they are born blind. Approximately 7-10 days after they are born their eyelids begin to open but it takes a couple weeks for their vision to fully develop. When their eyelids open, their vision is poor. Kittens may be able to see general lights and shapes, but their vision is unfocused and blurry.
Around 4 weeks of age, kittens begin to develop depth perception that helps them start to jump around, climb, and play with their litter mates. When kittens are approximately 6 weeks old, their eyesight continues to become sharper and more focused. Many people notice that kittens are born with blue or grey colored-eyes, and it is around this period of development that their eye color begins to change to the color they will have as an adult.
A kitten's vision will continue to develop within the first couple months of their life and is usually completely developed by the time they are 4 months old. It is important for cat caretakers to know that between 4-12 weeks of age, kitten's eyes go through a sensitive period where their visual development is prone to disruption under poor conditions (Bonds & Freeman, 1978; Bateson, 2013). After kittens go through this sensitive period and have fully developed vision, they will end up with a 200-degree field of view, 30 degrees of peripheral vision, poor binocular vision, and dichromatic color vision (CFHC, 2014).
As a kitten's eyesight develops, they begin to observe their mother and other familiar felines and learn important predatory behaviors. They also develop paw-eye coordination. This helps prepare the kitten for adulthood and develop the ability to hunt and capture prey and to defend itself. Cats will continue observing and learning from other cats as they mature, which is why pet cats may end up picking up different behaviors (sometimes problematic ones!) if they live in a multi-cat household (Bateson, 2013).
What Are The Similarities And Differences Between Human Eyes And Cat Eyes?
Most mammals have similar eye anatomy, including humans and our cats. The purpose of our eyes is to take in information from the environment around us and send that information to the brain to help us function in that environment. Our eyes are important and need to be protected. Our eyes sit in an eye socket called an orbit, which contains nerves, muscles, and blood vessels. The sclera is the white of your eye and is covered with a membrane called the conjunctiva. When you get pink eye, it is the conjunctiva of the eye that gets inflamed (inflammation or infection of the conjunctiva is known as conjunctivitis). The cornea is at the front of the eye and is surrounded by the iris with the pupil in the middle (the black part of the eye). These structures help to control the amount of light that reaches the retina. The retina is in the back of the eye and contains photoreceptors. Mammalian eyes contain two primary types of photoreceptors on the retina: cones and rods. Cones are responsible for color vision and rods are responsible for vision in low light (Gelatt; Jacobs, 2009).
Compared to humans, cats have fewer cones in their eyes. This results in cats having blurrier vision than humans. If an item is about 20 feet away, cats can see the item sharply, but anything farther than that will be less clear to them. Having fewer cones in their retinas also results in cats having dichromatic vision. This means that they primarily see blue, yellow, and gray hues, similar to humans that are red-green colorblind (Clark & Clark, 2016). Recent evidence has suggested that cats may even have the ability to see ultraviolet light, which would explain why sometimes cats appear to be seeing things we do not (Douglas & Jeffery, 2014).
Contrary to popular belief, cats cannot see in complete darkness. There needs to be at least a tiny bit of light for them to be able to see. Cats have more rods in their eyes when compared to humans, meaning they are better at seeing in very low light, which has led to the belief that cats can see in darkness. Although domesticated cats tend to adopt the daily activity patterns of their owners, they have historically been known to be active at dawn, dusk, or night, which is why they have evolved to have more rods than us (Brown & Bradshaw, 2013).
Cat eyes are designed for hunting and stalking in low lights in other ways as well. Cats have thin, vertical pupils, which are common in predatory animals that need to see in both low light and bright light. The shape of the pupils allows the animals’ eyes to adapt to multiple lighting conditions by restricting the amount of light getting into the eyes. This is done by restricting the pupil size in bright light or allowing more light to get in by widening the pupils in low light (Banks et al., 2015). Their pupils can open much wider than ours, allowing them to capture more light.
Cats also have a membrane that helps reflect light from the back of their eye through the photoreceptors, called tapetum lucidum. This membrane is what causes cat eyes to glow brightly in pictures or other bright lights (Commings, 2006). While these features make it so cats can adapt in environments with low or bright lights, cats do appear to be more sensitive to light brightness than humans so this should be kept in mind in any environment a cat is kept in (Stella & Buffington, 2013). The structure of the cat eye puts them at a disadvantage when it comes to slow moving objects compared to humans, and this is primarily due to them being primed for seeing quick moving prey instead of slower moving objects (Brown & Bradshaw, 2013).
In addition to using their eyes for sight, cats also use their eyes to recognize familiar cats and to communicate with one another. Cats widen their eyes when they feel threatened, will stare at each other when they are being aggressive, and blink slowly when they feel content and safe. Cats tend to follow these same rules when communicating with humans. Staring at a cat can make them feel threatened and uncomfortable. To make a cat feel safer, avert your gaze away from them and offer them slow blinks. This will help communicate to the cat that you are not a threat and can be trusted (Springer, 2008; Brown & Bradshaw, 2013).
Cats also use other forms of visual communication through body posturing to communicate their mood to other cats and to us. Their ears, facial expressions, back posture, and tail can all communicate whether a cat is relaxed and content, angry, or fearful. During cat-cat conflicts, cats will posture at each other and visually assess their opponent to decide whether it is worth fighting for resources or retreating to safety (Brown & Bradshaw, 2013).
Cats are also known to scratch surfaces. This not only helps maintain proper claw health and function, but also serves as a form of communication with other cats. Scratching surfaces leaves an olfactory and visual mark indicating a cat’s territory (Stella & Buffington, 2013). As mentioned before, it is also believed that cats may be able to see ultraviolet lights. As many cat owners know, UV lights can be used to detect cat urine, so this UV vision may help cats identify urine markings of fellow cats, as well as possibly find urine markings of their prey or predators as well.
Are Cats Able To Visually Recognize Human Faces?
Few studies have looked at how cats view human faces and whether or not they have facial recognition with familiar humans. When compared to dogs, cats only showed facial recognition of a familiar human about 50% of the time, whereas dogs chose the familiar human face 88% of the time. However, cats were better than dogs at identifying a familiar conspecific. Cats chose the face of a familiar cat 90% of the time, and dogs chose the face of a familiar dog 85% of the time (Lomber & Cornwell, 2005). The results of this research may indicate that cats use other senses to bond with humans compared to dogs and may recognize us by scent or sound instead.
What Eye Diseases Are Cats Prone To?
Sight is important to cats, and they are prone to a variety of eye diseases. Discharge from the eye, redness, or repeated scratching at the eye can be a sign that your cat needs to take a trip to the veterinarian. Some breeds, including Siamese, Burmese, and Persian cats, are more prone to eye diseases such as conjunctivitis, corneal ulcerations, and glaucoma, but all cats can be at risk (McLellan & Miller, 2011; CFHS, 2014).
Aging cats can begin to lose their vision for a variety of reasons such as infections, glaucoma, and cataracts but they can adapt very well to reduced eyesight because their senses of smell and hearing are highly developed. Some causes of blindness can be treated or improved with veterinary care, so if you notice your cat cannot see as well, consult a veterinarian instead of assuming old age is the only reason. If your cat starts losing their sight, it’s important to try to keep the layout of your house the same so they can navigate around easily. You can also use verbal cues to let your cat know where you are in the house and communicate with them to prevent frightening them (CFHS, 2014).
What Do We Know About Cat Vision?
Cats have a unique way of viewing the world, and as cat parents, it is important for us to recognize this. If we understand how a cat’s vision works, we can help design their environment to set them up for success. We know that kittens do not develop their eyesight fully until 3-4 months of age and that there are critical sensitive periods in which they need the right environment in order to develop healthy vision. We know that cats generally have poor vision and can best see items that are within 20 feet of them. Cats also cannot see items directly beneath their nose.
With this information, we can understand that cats may not be able to fully recognize a human or object from far away or be able to see an item right under their nose and that us caretakers can be more understanding of these limitations in their vision. We also know that cats are well-adapted to seeing in low light and that they may be able to see UV light, explaining some of their strange cat behaviors. Cats see blue, yellow, and gray hues best. Therefore, these might be the best color toys to get for your feline friend. Ultimately, vision is an important sense to your cat and a veterinarian should address any issues that arise with their eye health and vision.
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