Guinea pigs are born with their eyes open, but how do they see the world?
For all the time humans have spent with them, there are still a lot of questions when it comes to guinea pigs and we don’t always have answers about how their adorable bodies work. Researchers have generally been so busy performing experiments on them that they haven’t gained a lot of information about them.
Here’s what we do know, though—in a nutshell, they probably don’t see any better in the dark than we do.
How Well Do Guinea Pigs See in General?
Guinea pigs seem to see ok, but they see differently than humans do. Since their eyes are set more to the sides of their heads, they have good peripheral vision. They can see an incredible 340 degrees around, which gives them a much larger field of vision than we have.
That said, their eye position gives them poor depth perception. For depth perception to work, an animal needs binocular vision; that is, they need to see the world through both eyes at a time.
Since guinea pigs see most of the world out of each eye, independently, it’s probably harder for them to judge how far away things are or how far apart things are from each other. In addition, they can only see 3-5 feet, so long-range vision isn’t really their forte.
That might surprise you if you’ve ever hung out with guinea pigs and noticed their unerring instincts for knowing exactly when humans enter the room with favourite treats. Or noticed that your guinea pigs seem to find their way around their cage just fine at night.
But that’s because guinea pigs have adapted to use other senses that are a little better than their vision.
How Do Guinea Pigs Navigate the Dark?
Despite not seeing very well in the dark, guinea pigs really do manage to get around. They can find their way in the dark thanks to a few special traits that are more effective than their vision.
For example, what the guinea pig lacks in vision, they more than make up for in spatial memory. While it’s usually rats and mice who are made to run mazes in labs, guinea pigs have also demonstrated that they’re handy with spatial learning tasks.
One study found that domestic guinea pigs actually outperform their cousins, the wild cavy, when tested on their spatial learning abilities.
Guinea pigs also have something scientists call “vibrissae” on their muzzles. We know them better as whiskers. These are actually specialized hairs that have high numbers of nerve cells surrounding the hair follicle.
Guinea pigs use their whiskers to feel their way around, in much the same way we use our hands. Much like our sense of touch, whiskers help a guinea pig determine the size, shape and texture of things around them, which helps them forage and locate objects.
Whiskers are so sensitive that they can feel vibrations in the air, which tells cavies if something is moving nearby, like a predator (or a sassy friend who’s about to ambush them).
In addition to this extra sense of touch, guinea pigs have incredible senses of smell and hearing. This won’t come as a surprise to guinea pig owners, who have to work awfully hard to hide the rustling sound of a treat bag or the smell of a freshly cut carrot.
These finely honed senses don’t just help cavies find food, although that’s probably most of what your piggie is using them for. They help guinea pigs know when threats are coming close and help them identify friends and foes among their social groups.
Are Guinea Pigs Nocturnal?
Guinea pigs aren’t nocturnal—exactly what they are is a question under debate, though. The Merck Veterinary Manual says guinea pigs are diurnal, meaning they’re active during the day.
Other people say they’re crepuscular, which is what we call animals who are active at dawn and twilight. In a 1994 study on guinea pig vision, however, researchers Gerald H. Jacobs and Jess F. Deegan II explain that guinea pigs were crepuscular in the wild, but they’re not in the lab.
In the lab, they say, guinea pigs “may display essentially continuous activity” whether it’s constantly light or constantly dark.
That tracks with a lot of guinea pig owners’ experiences. Plenty of owners are woken every night by the sound of piggies playing, munching and exploring when it seems like by anyone’s reasonable standards, they should be asleep.
According to the Smithsonian, guinea pigs spend 4% of their days sleeping, and sleep only for about 6 minutes at a time. Hence, all the micro-naps your piggie takes during the day. But if it seems to you like your cavies are up all. the. time., you’re right. They are.
Do Guinea Pigs Need a Light at Night?
As you can tell, even though your piggie might be active at night, and even though their vision isn’t great at night, they don’t need a light to help them. In fact, it’s better to let them spend the night without one.
Cavies are prey animals, and they feel safest when they’re huddled away. One of the reasons they love their tunnels and their blanket forts so much is that it’s dark in there, so keep the lights off at night so your guinea pig can feel safer and less stressed.
Do Guinea Pigs See Colours?
They do see colours. Jacobs and Deegan’s research proved that guinea pigs are dichromats—that is, they see two colours (blues and greens to be exact). To give you a comparison, humans are trichromats, which means we see three colours (blues and greens and also reds). If we were to look at the world through a guinea pig’s eyes, it would look like someone had put a blue filter all over everything.
Monochromats see in black and white, along with all the greys in between. Most mammals, in fact, have dichromatic vision, including cats and dogs. Many primates, including humans, have additional cones in our eyes that give us trichomatic vision. But humans don’t have the most advanced vision in the animal world.
Most birds and fish, as well as lizards, have cones that give them tetrachromatic vision. That means they can see blues, greens, reds and ultraviolet. And the mantis shrimp has 12 different colour receptors in their eyes, so the world of colours that we see is not nearly all the colours of the rainbow.
Conclusion
We hope that answers some of your questions about these neat little creatures and the incredible ways they’ve adapted to move around in the dark, keep themselves safe from predators and sense when cilantro is about.
