Guinea pigs can make great family pocket pets. Some guinea pigs seem to be more busy at night than during the day. But how good can your guinea pig see in the dark? Do they need a nightlight to help them see at night? Can guinea pigs see in the dark? Dr. Jess explains all of these answers and more below:
Guinea Pig Basics:
A guinea pig is a type of pocket pet that resides in the cavie family of animals.
They are small animals that grow to a maximum of approximately 10-11 inches long, and can weigh up to 2.5 pounds as a healthy adult.
In captivity and with proper care it is quite common to see these pets live up to 8-10 years of age.
One of their main anatomical (body) “quirks” is that they are constantly needing to chew in order to file their teeth down, as their teeth are constantly erupting (growing longer and longer).
They are quite playful animals and love to socialize with the ones that they know and love.
They make great pets for responsible pet owners, and those living in small dwellings wanting a loveable pet that comes in a small package.
Guinea pigs are born with two eyes, with the exception of those who are born with less or who have their eyes removed for medical reasons.
Guinea pig eyes are a lot like human eyes in how they are designed and how they work.
The outside of the eye is called the cornea and can be easily scratched by nails and other hard pointy objects. The cornea is transparent to the naked eye and must be lubricated by the eye and eyelid to stay healthy.
The white part of the eyeball is called the sclera and the colorful part of the eye is called the iris. Guinea pigs can have different colors of iris. The most common color of iris is brown, but other colors can occur.
The iris is in charge of letting light into the eye, by making the pupil, the black circular section in the middle of the eye, smaller or larger depending on the need for more or less light into the eye.
The pupil dilates (gets larger) to let more light in, and the pupil constricts (gets smaller) to let less light in.
The lens is behind the iris and helps to send the light to the retina at the back of the eye.
The retina has many photoreceptors and will send the information to the brain to process what the eye is seeing.
The eye is surrounded by soft, moist, pink tissue called conjunctiva to help protect and cushion the eye and an upper and lower eye lid also help to protect and guard the eye too.
The surrounding tissue also contains tear ducts that release tears onto the eye’s surface to help clean, flush out, and lubricate the surface of the eye.
The tears of the guinea pig contain multiple substances, including enzymes that help protect the surface of the eye from invaders, such as certain bacteria.
How Does an Animal See? Eye Function:
Pretty much all animal eyes work in the same basic manner. Light is allowed in the eye in various degrees, depending on the eyes structure and adaptations, which can differ depending on the animal in question.
The light is brought into the eye and onto the retina at the very back of the eye.
The retina has many photoreceptors and will send the information it receives to the optic nerve and on through to the brain to process what the eye is seeing to form a picture for you of what you are observing.
What Allows Animals to See in the Dark?
Owls and other animals with excellent night vision have special adaptations that help them see well in darker environments. These are a few physical attributes that these animals have that help them see so well in the dark:
The tapetum lucidum is a very thin, reflective surface behind the retina in the back of the eye.
It’s beautiful shiny, reflective surface allows light to reflect back into the eye after it’s passed through its original attempt.
So there is a second shot at retrieving the proper amount of light the eye needs in order to achieve the light that it needs.
Rods & Cones:
The cones in our eyes allow us to see different colors, or wavelengths of light. The more types of cones (color receptors) one has, the more colors that one can see.
One extreme example of an animal with many cones, is the mantis shrimp, which has 16 types of cones in their very independent eyes.
This shrimp’s color receptors (AKA cones) allow them to pick up on small changes in color that their predators may not, allowing them to flee from danger more easily.
In fact, their eyes are so independent, that they can move independently of one another, much like a chameleon can move its eyes.
Certain wild animals like wild cats, foxes, and even snakes, have vertical slit-shaped pupils that allow them to better see at night and have better depth perception too.
How Well Do Guinea Pigs See?
Guinea pigs do not have the best vision around, but they also do not have the worst. Let me dive a little bit deeper here and get more specific.
Studies have shown that guinea pigs have 340 degree eyesight.
340 degree eyesight means that they have very good peripheral vision. It means that they can almost see 360 degrees, all the way around them.
Their eyes, which are set on the sides of their head, are placed purposely off to the side of their head in order for them to have better peripheral vision, much better than us humans!
Other guinea pig studies show that guinea pigs can see colors [source], but to what degree that they can see colors is still undecided.
For the most part, most can agree that guinea pigs can definitely see colors such as green [source], but to what degree that they see other colors, is still undetermined and up for debate.
One area where guinea pigs do not do well with is in the depth perception department.
They have quite poor depth perception, only being able to see up to about 3-5 feet away before their sight becomes more and more blurry.
Because of this poor depth perception, this small prey animal must use its other senses, which are much more reliable, so survive and to help them move about, espcially in the dark.
Can Guinea Pigs See in the Dark?
Well, one thing that is widely known, is that light is needed to see in the dark.
No animal can see anything in complete lack of light or complete darkness.
For an animal to see, light enters the eye and then is sent to the back of the eye, where receptors transfer what was seen through the optic nerve and then on to the brain to be processed into a picture of what the being is “seeing”.
It’s a process with many steps that happens in less than a split second. But it all starts with at least a little bit of light.
Therefore, it is safe to say that guinea pigs can not see in complete darkness.
But then there is the debate on how well they can see in dark or darker environments…
Guinea pigs can not see very well in the dark. They do not have the adaptations that other animals that can see well at night have.
Therefore, guinea pigs must rely on other senses to help guide them at night so that they can move about and sleep safely and to stay away from their predators.
Senses to Help Guinea Pigs ‘See’ at Night:
Sense of Smell:
Guinea pigs have a great sense of smell. This sense of smell can help them to help them “see” at night when combined with other senses and adaptations discussed below.
Vibrissae, also known as facial whiskers on animals, can very similarly to cat whiskers it is thought.
These whiskers help your guinea pig measure distances and figure out shapes that they can sneak in and out of even when they can not see well.
If their whiskers get bumped, the guinea pig will know that something is nearby their face. These whiskers help them to “see” better in the dark.
Spatial memory is a termed used to describe when a being is able to remember where things are placed or where routes of traveling occur, a mental map of where things are located in their little world.
What Animals Can See Well in the Dark?
To see well in the dark, some animals have special features that allow them to be better equipped for darker environments than other animals.
For instance the owl has a few adaptations that make it very easy for them to see extremely well at night.
For starters, they have tubular-shaped eyes that are quite large for their bodies when compared to other animals of similar size.
Their eyes are also much more sensitive to light due to the large number of rods in their eyes (retinas) and the fact that they also have the tapetum lucidum to help them see at night as well.
Also, the way that their iris in their eye can adjust, the iris can widen a lot to allow even more light in at night than most other beings – remember, no matter if it seems dark out or not, light must enter the eye in order for anything to “see” in the dark.
Animals can not see in complete darkness because of the lack of light!
Sharks are another animal that can see well in the dark… and in the water too! This is because they have the tapetum lucidum to help them out as well.
Another animal with amazing night vision is the frog. Frogs can see colors in very very dark environments, far better than us humans or most other animals ever could imagine, because of the contrast that they see due to differing types of rods in their retinas!
Do Guinea Pigs Prefer to Sleep in the Dark?
Guinea pigs are crepuscular, meaning that they are most active at dawn and dusk, when the sun is either rising or setting.
But just because they tend to be active at dawn and dusk, does not mean that they do not like to sleep in the dark.
Guinea pigs do like to sleep in the dark.
The darkness allows them to feel more protected and safe because it is harder for predators to see or find them.
And this ‘safe’ feeling has been passed on from the wild guinea pig, onto the domesticated guinea pig that we bring into our homes and call our pet.
Do Guinea Pigs Sleep With Their Eyes Closed?
Guinea pigs can sleep with their eyes open, even though not all piggies will sleep with eyes open.
Usually guinea pigs will sleep with their eyes open when they feel that they need to stay alert and ready to flee at any given second. This is important for guinea pigs out in the wild, but not so much for domesticated pet pigs.
When a guinea pig becomes more comfortable with their surroundings, then they may someday close their eyes, or at least partially close their eyes, when sleeping.
Guinea pigs can see in the dark, but not very well. That is why guinea pigs have adapted by using other senses, to help them maneuver and navigate in dark settings.
These senses and adaptations, such as great smell and good hearing, as well as whiskers, help make dark environments easier to “see” in.
Not all of a guinea pig’s sight in dark situations is done with their eyes.
Because guinea pigs can easily navigate their surroundings without light, it is not necessary to provide them with artificial light or night-lights at night in their enclosures.
They do just fine without any help!
If you are worried about your guinea pig’s eyesight, contact your local loved veterinary immediately to discuss further exploration into the issue.