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Why Do Dogs Like To Sunbathe?

Many dogs love to sunbathe. For example, you might notice your dog sleeping in a patch of indoor sunlight on a winter’s day, or settling down in direct sunlight during the summer months. Why is this?

The simple explanation is that it’s a pleasant feeling! Just like humans, dogs enjoy the warmth and comfort provided by sunbathing. Resting in the sun can also help with temperature regulation, generate vitamin D, and provide mild pain relief for sore joints.

Let’s take a closer look at why dogs like to sunbathe and whether you should be concerned about this behaviour.

Why Do Dogs Lie In The Sun?

why do dogs like to sunbathe

Warmth And Happiness

Laying in sunlight isn’t a behaviour you should be concerned about. Sunbathing is an enjoyable activity for dogs, as the warmth provides a sense of comfort and relaxation.

It’s also thought that sunbathing releases serotonin in a dog’s brain. Serotonin is a neurotransmitter that helps to regulate happiness, which is why it’s sometimes referred to as a “feel good” hormone.

Aside from feeling pleasant, resting in sunlight can also regulate your dog’s body temperature. The sun’s heat keeps the dog warm while conserving their energy.

Vitamin D Production

Unlike humans, dogs should get enough vitamin D from their food. They can still get small amounts of vitamin D from sunlight though, which may be another reason dogs instinctively enjoy sunbathing.

Vitamin D regulates the amount of phosphate and calcium in the body, making it vital for healthy bones and teeth. As calcium is involved in muscle contraction, vitamin D is also essential for muscle health.

In humans, sunlight converts a precursor to vitamin D on the skin into inactive vitamin D. It can then be absorbed into the body, where it makes its way to the kidneys and liver. At this point, it’s converted into vitamin D3, which is the active form.

Dogs have the same precursor on their skin, which is converted into vitamin D by sunlight. However, their fur prevents most of it from being absorbed, so it only enters the dog’s body when they lick their fur.

As you can imagine, licking is much less effective! For this reason, dogs get nearly all their required vitamin D from food (assuming they eat high-quality and nutritionally complete food). The advantage of getting vitamin D through diet is that dogs are unlikely to become deficient in this vitamin through lack of sunlight. 

Still, there might be a leftover instinct for dogs to lay in the sun to ensure they get enough vitamin D.

Blue paw

Vitamin D Poisoning

Vitamin D is essential for maintaining a healthy calcium and phosphorous balance in the body. But excessive vitamin D can be very harmful to dogs, especially if it’s ingested in a large single dose.

Large amounts of vitamin D causes a dog’s body to calcium to be pulled from the bones and absorbed from foods. This leads to high levels of calcium (hypercalcaemia), which can result in symptoms such as twitching, seizures, muscle damage, and kidney damage.

Pain Relief

Another potential reason for a dog lying in the sun is that it can provide pain relief.

Many joint conditions are worse when the muscles and surrounding tissues are cold. By resting in the sun, your dog may gain some relief, particularly when she first gets up.

Potential Risks of a Dog Sunbathing

A spaniel in the sun

Sunbathing isn’t a worrying behaviour for dogs. It’s a naturally pleasant activity that provides warmth and a sense of comfort, so resting in the sun isn’t a sign of illness.

However, sunbathing can be potentially dangerous if your dog lies in the hot sun for too long or the conditions are hot. Let’s go through some of the risks associated with sunbathing and when you need to take action.


Heatstroke is one of the biggest risks of sunbathing. It occurs when the dog’s body temperature exceeds 104°F (40°C), causing a variety of symptoms.

Dogs are more prone to heatstroke than humans, as they can’t sweat through most of their body. Instead, they rely on panting to keep cool, which is much less effective at reducing body temperature.

If a dog lays in the sun for too long on a hot day, there’s a real risk of the dog’s body overheating. This can happen to any dog, but is more likely if the dog is a puppy, elderly, unwell, overweight, or a brachycephalic breed (such as pugs or bulldogs).

The key is to monitor your dog and move them out of the sun before there’s a risk of overheating. Don’t assume your dog will move when they get too hot, as many dogs won’t realise there’s something wrong until it’s too late.

While you should always focus on prevention, it’s also essential to be aware of the signs of heatstroke. Some examples include:

  • Excessive panting and drooling (these symptoms are often the first warning signs)
  • Lethargy
  • Red gums
  • Fast heart rate
  • Vomiting
  • Loss of coordination
  • Loss of balance
  • Diarrhea
  • Shaking
  • Seizures

Heatstroke is a life-threatening condition that requires urgent veterinary care. So, if you notice these symptoms, immediately move your dog to a cool location and take them to the vet. It’s also a good idea to offer your dog a drink, but don’t force them.

To prevent heatstroke due to sunbathing, always monitor your dog when they are in the sun and don’t let them outdoors when it’s hot. Avoid exercising your dog during hot weather and always provide access to a cool, shaded location. You may also want to read our guide to keeping dogs cool.


Dehydration is another risk for dogs who sunbathe for extended periods in hot weather.

Dogs pant to cool down, as the water evaporation helps regulate their body temperature. However, this can cause dehydration if the water isn’t replaced.

Symptoms of dehydration include:

  • Excessive panting
  • Thick saliva
  • Dry nose
  • Sunken eyes
  • Lethargy
  • Dry gums

Just like heatstroke, you should always contact a vet immediately if you notice signs of dehydration. This is a life-threatening situation that could require medical care. Once dehydration begins, a dog may need intravenous fluids to recover.


All dogs can suffer from sunburn – especially if they enjoy sunbathing outdoors.

Dogs with white fur, short coats, or hairless breeds are most at risk. Dogs who sunbathe on their backs are also more likely to get sunburned, as the stomach skin is less protected by fur.

The best way to avoid sunburn is to limit your dog’s time in direct sunlight. This also reduces the risk of heatstroke and dehydration.

You may also want to consider applying a dog-safe sunscreen. Look for an unscented and waterproof sunscreen, as dogs usually don’t like scented products.

Here are some tips for applying sunscreen to your dog:

  • Test a small amount of sunscreen on a patch of skin. Check that it doesn’t trigger an allergic reaction before applying it elsewhere on the body.
  • Be careful to avoid the eyes when applying sunscreen.
  • Make sure to cover the regions most prone to sunburn. Examples include the ear tips, groin, inner thighs, stomach, and nose bridge. 
  • You may need to distract your dog while the sunscreen is being absorbed, otherwise he might lick it off. This typically takes around 15 minutes, but check your sunscreen instructions.
  • Re-apply the sunscreen every four hours. You may also need to reapply it if your dog goes swimming.

Note: Don’t use human suncream, as it may contain para-aminobenzoic acid or zinc oxide. Both are toxic to dogs if licked off the skin.

Skin Cancer

Repeated sun exposure can increase the risk of skin cancer in dogs. So, it’s important to limit how long dogs lay in direct sunlight.

There are a variety of types of skin cancer that can affect dogs, including mast cell tumours, malignant melanomas, and squamous cell carcinoma.

A common symptom of skin cancer is new lumps appearing on the dog’s body. Other symptoms depend on the type of cancer, with examples including sores, raised and hard blemishes, and limping.

How Long Should You Let a Dog Lie In The Sun?

There’s no set duration for how long dogs should be in the sun. A safe sunbathing time varies a lot depending on the temperature and weather, along with the dog’s age and health.

For example, there’s nothing wrong with a dog resting in a patch of indoor winter sun for as long as she wants. In contrast, even a short time spent sunbathing during intense summer heat could be dangerous.

As a general rule, avoid letting your dog lay in direct sunlight during the hottest hours of the day. Monitor them closely for signs that they are getting too hot, and always provide plenty of shade and water. 

In particular, pay close attention to the early signs of heatstroke or dehydration. Excessive drooling or panting are both signs that your pet is overheating. You should contact your vet immediately if you notice any signs of these conditions.

Frequently Asked Questions

Is Sunlight Good For Dogs?

Sunlight provides a range of benefits for dogs. Aside from keeping a dog warm and comfortable, it regulates serotonin levels and provides a small amount of vitamin D.

Sunlight in the early hours can also maintain a consistent circadian rhythm. The sunlight signals to the brain that it’s morning, which delays melatonin production until later in the day.

Too much sun exposure can be a bad thing though. Sunburn, heatstroke, and skin cancer are all potential risks due to a dog laying in a sunny spot for too long.

Can Dogs Get A Tan?

Dogs can get a tan, although their fur usually covers it up. However, getting a tan is not beneficial for a dog, and regular exposure to direct sunlight can increase the risk of skin cancer.


Sunbathing is relaxing for dogs. Laying in the sun can even cause the release of serotonin, which is a neurotransmitter involved with happiness.

Too much sun can be dangerous though – particularly on hot days. Resting in the sun can potentially cause heatstroke, dehydration, sunburn and increase the risk of skin cancer, so it’s important to limit your dog’s time in direct sunlight.

Do you have any questions about why dogs like to sunbathe? Please use the comments form below to get in touch.


Richard Cross

Richard is a journalist who specialises in dog behavior. He's written hundreds of articles and books related to dogs, including for the Continental Kennel Club, Dog Fest (the UK's biggest dog festival) and various veterinary surgeries. When he's not spending time with Jess and Rudy (his beloved Labrador and Golden Retrievers), he enjoys reading, hiking and watching sports.
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