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Do Guinea Pigs Need Sunlight? [What Are Their Requirements]

If you are a new guinea pig owner, then one of your early considerations is likely to be around their natural light requirements. What about the sun; do they require any exposure and is this something they need? Where does Vitamin D fit in? This is what you should be aware of.

So, do guinea pigs need sunlight? Guinea pigs do require some natural sunlight. However, moderation is key and they should not be exposed to direct sunlight or very hot temperatures for too long as it could result in heatstroke. Mornings and evenings are the best times to take them outside when it’s naturally cooler.

It’s a great idea to ensure they have access to water and shade during these times too.

Plus, make sure it’s actually safe for them to roam and explore, well ahead of time.

Let us now take a closer look at the topic to see whether guinea pigs prefer lighter or darker conditions, how much sun a guinea pig needs, whether they need to be outside, and vitamin D requirements.

Do Guinea Pigs Prefer Light Or Dark?

Guinea pigs are prey animals and are used to hiding from predators in the day. For this reason, guinea pigs prefer the dark, as they can move around without being seen.

Guinea pigs are crepuscular animals.

This means that they are active during the day and during the night. They don’t go into a deep sleep, it’s more a state of rest, where they even keep their eyes open.

For this reason, many people believe that they need to provide light during the nighttime, which is not true at all.

It’s not a requirement and guinea pigs do perfectly well without them.

Guinea pigs naturally respond to their environment and are able to keep themselves entertained whether it’s light or dark.

This also leads us to our next question; do guinea pigs prefer light or dark?

Even though your home is perfectly secure, and there are no threats to your pet’s safety, they will still prefer to be in the dark.

This is a biological and evolutionary instinct that will always be present within them.

Therefore, you can reduce your cavies stress levels by keeping them in a pitch-black room in your house.

Guinea pigs have poor eyesight, so they rely on memory to escape danger in the wild.

They can run quite fast, and hide inside tunnels, and among the grass, simply by remembering routes.

This ability, helps pet guinea pigs navigate their way inside their cage, having a keen sense of hearing and smell is a bonus.

This is also why you see a lot of tunnels and hideaways available on the market, and why experts and veterinarians recommended that you get some for your guinea pig(s)

Guinea pigs also like to sleep in the dark and will sleep in increments that last a few minutes at a time. They sleep during the day but not as much.

Your cavy will feel more secure and relaxed in the dark than when it’s bright and will take longer naps during this time as a result.

Many guinea pig owners think that they need to provide a light, but, from your pet’s point of view, it is unnecessary.

Knowing that guinea pigs prefer the dark, and they are instinctively primed for it, we know face the next question, and that is do guinea pigs need sunlight?

Let’s explore this in more detail in the next section.

How Much Sunlight Do Guinea Pigs Need?

When it comes to letting your guinea pig out in the sun, moderation is the key. While sunlight is beneficial for humans and other animals, it can be dangerous for a guinea pig. If you do decide to allow your cavy out in the sun, you must be vigilant at all times; the chief reason being is that they are prone to heatstroke.

Guinea pigs don’t have sweat glands, their bodies regulate by constricting their blood vessels when it’s cold, the blood rushes to the torso to warm up internal organs.

When they get too hot, blood vessels dilate so heat can be sent out of the body and into the atmosphere.

A guinea pig will try to keep cool by staying in the shade.

So, you must be sure to provide shade at all times during any time of sun exposure.

This will help them to naturally regulate their body temperature and signal to you that they have had enough.

f the temperature of their environment gets to about 86 degrees F, as low as that appears to be, they can develop heatstroke within minutes, and die.

If you wish for your guinea pig to experience the sun, you’ll therefore need to be careful and vigilant around how you approach it.

Here are some suggestions:

  • Never place their cage in direct sunlight. Especially through windows, as this can exacerbate and amplify the heat
  • The best time to take your cavy out in the sun for some exercise is mornings and evenings when it’s cooler.
  • Make sure you have fresh water available and that they can consume to cool down.
  • Make sure their enclosure is in the shade, as heat can build up inside, this is especially dangerous if it’s made from plastic.

Do Guinea Pigs Need To Be Outside?

Indoor guinea pigs do require some (limited) time outside. While they are happy indoors as well as outdoors (as long as they have enough space to exercise), some time to run around outside is actually good for them.

Guinea pigs also need time outside of their cages, as they are naturally curious and playful.

When you do allow your guinea pigs time outdoors, make sure that you don’t let them out in bad weather, and don’t let them out for too long in the sun.

It’s a good idea to invest in a secure and durable playpen.

This way you can let them freely roam without running away or potentially hurting themselves or anything around that poses a threat.

There are specific brands, like the You&Me below, that provide a cover that can be used as a floor mat or as a way to shield your guinea pig from the shade.

You & Me Run & Play Space Small Animal Playpen, Medium
  • Fully assembled and ready to use
  • Heavy-duty mat included
  • Durable steel panels
  • Allows your pet to exercise and play while staying secure

Guinea pigs can live outdoors, but you must make sure that their living conditions are safe, comfortable, and protected from the elements.

You must keep them safe from predators, as dogs, cats, and foxes can get into their living quarters and do serious harm.

You must not let your guinea pig come to any harm, bring them indoors if there are animals on the loose in your area.

Aside from predators, electrical cables, poisonous plants, and pesticides, could seriously compromise your guinea pig’s life.

Do Guinea Pigs Need Vitamin D?

It is established that time outside and in the sunshine comes with some risks for your guinea pig, but that shouldn’t deter you from taking them outside and getting some natural sunlight.

While they only need limited amounts, they do need some to thrive.

This is because, like all plants and animals, guinea pigs need vitamin D.

Vitamin D facilitates the absorption of calcium from the intestine which is eliminated by the kidneys.

This action prevents kidney and bladder stones from forming, which are, health complications that guinea pigs are more naturally prone to.

A deficiency of vitamin D can equally cause the kidneys to store more calcium.

While only making up around 5-10% of the diet, you must buy good quality pellets.

Poor quality brands typically have an excess of vitamin D which is equally as bad as not enough.

This again makes it hard for the kidneys to undertake their role and eliminate calcium.

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Now, you may think that putting your guinea pig by a window will be enough for a guinea pig to obtain their Vitamin D requirements.

However, unfortunately, this will not work.

Glass absorbs UVB which is needed for the development of vitamin D3 – the more active and preferential form of the vitamin.

So, ultimately, your guinea pig will need some time outdoors in direct sunlight.

If however, you are nervous about letting your guinea pig outside in the sun, you can purchase a UVB lamp which is commonly used for pet reptiles.

This lamp can get very hot, but the good news is that it doesn’t need to be on for very long.

An hour in the morning and the evening will be more than enough for your guinea pig to acquire the light it needs.

UVB lamps can safely double a guinea pig’s vitamin D3 value within a couple of weeks.

This is because the bulbs emit the same rays as the sun.

However, bulbs should be changed every six months to a year to ensure potency and/or according to the manufacturer’s instructions.

Another option that some guinea pig owners report is using vitamin D drops.

However, these should only be used temporarily, and with caution, as overdosing can so easily happen.

An overdose of vitamin D can come with severe health consequences.

A lot of the Vitamin D drops on the market are aimed at humans and establishing an effective and healthy dose for your guinea pig is difficult and problematic.

It is advised if that you are interested in this route that you speak to your vet or a specialist.


It’s good to allow your guinea pig time outside and they do need sunlight.

However, you must be very vigilant, as too much sun or too high heat can pose significant health risks like heat stroke.

When taking them outside, you also need to consider that they are very vulnerable to the elements and to other predators.

You’ll need to be close by at all times, and be sure to provide plenty of shade and water at all times.

It’s also a good idea to opt for the early mornings or late afternoons – this will ensure you are not taking your guinea pig out in the heat of the day.

As their owner, it is your responsibility to provide everything that they need, like sunlight.

However, you must also play the role of protector, and ensure that they come to no harm in the process.

And if you are looking to learn even more about guinea pigs, and their behaviors traits, and tendencies, my following guides may be of interest to you: