Common Behaviors of a Female Dog in Heat

Alianna Munakata

Published by Alianna Munakata

Reviewed by Diana Wells

Updated on

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When your dog is acting weird, she might be experiencing common behaviors of a female dog in heat.

If this is the first time you have a dog or have not yet sterilized your pet, we will tell you everything you need to know about heat in dogs, what it is, and the proper care to prevent her from getting pregnant.

What Does A Dog In Heat Mean? 

Estrus in female dogs is the period of fertility in which she will try to find a male dog to mate. Many of the factors of estrus, such as frequency, duration, and severity, depend on the age and breed of the female.

During this period, the female dog goes through hormonal changes. These will cause both physical and behavioral changes. And it can be very stressful, as an owner, not knowing and recognizing the signs of female dogs in heat.

When Do Dogs Get Their Period for The First Time?

Puberty is the time when female dogs become sexually mature and able to reproduce. In general, this usually occurs around six months of age, but the reality is that the exact age can vary by breed. Or rather, depending on the size of the dog.

Small-sized dogs (Chihuahuas, Toy breeds, etc.) may start their cycle at around five months. Large or giant breeds (Old English Sheepdogs, Great Danes, etc.) may not have their first heat until 18 to 24 months.

The reality is that each body is different, and the onset of the cycle can be quite variable between individuals. Many times, the first heat is “silent,” meaning that there are no outward manifestations of heat. The owner will not realize until the next heat that the puppy has reached puberty.

How Often Do Female Dogs Go Into Heat?

The frequency of estrus depends on the dog’s size, breed, and age. Unspayed females come into heat twice a year, approximately every six months.

Smaller breeds may have three cycles yearly, while giant breeds may have one every 12 months. 

As the dog ages, the estrus cycle frequency may decrease. Yet, it will continue to go into heat throughout its life and may still become pregnant. Female dogs do not go through menopause. 

How Long Does A Dog Stay In Heat?

The average length of a female dog’s estrus cycle is about 18 days but can vary depending on the individual.

The Dog Heat Cycle Explained

To understand why the common behaviors of a female dog in heat occur, let’s first explain the reproductive cycle. It is the hormonal changes that happen in this cycle that dictate the physical and behavioral changes we will discuss later. 

What is the Dog’s Heat Cycle?

The female canine has two repeated phases: “Hormonal activity” and “non-hormonal.” The dog heat cycle consists of four stages

  1. Proestrus
  2. Estrus
  3. Diestrus, and
  4. Anestrus

The hormonal activity phase includes the Proestrus, Estrus, and Diestrous stages. The hormonal inactivity phase refers to the Anestrus stage.

infographic of the stages of a female dog's heat cycle


The first stage of the female reproductive cycle usually lasts seven to 10 days. Estrogens dominate Proestrus. Thus, the dog’s body begins to prepare for copulation. At this stage, the female attracts the male but generally does not allow mating.


This period lasts approximately nine days. Ovulation of several follicles occurs. So, it is the most fertile period of the reproductive cycle. 

The female allows the mating of several males in the same cycle and can have puppies from different dogs.

A prolonged estrus, ovulation of multiple follicles, and copulation with several dogs ensure the preservation of the species.


If fertilization of one or more eggs has occurred, the female will be pregnant for an average of 60 to 65 days. If gestation did not happen, the name of this stage is Diestrus. It is a stage dominated by progesterone, which lasts two to three months. There is no longer acceptance of the male.

It is at this stage where the so-called false pregnancy, psychological pregnancy, or pseudo-pregnancy occurs. It is a normal physiological hormonal condition that every female dog that has not become pregnant goes through—characterized by the appearance of physical and behavioral changes in the female canine. 

Females believe they will have puppies even though they are not pregnant. During the false pregnancy, they can produce milk, eat more, be aggressive, and make a “nest” for their supposed puppies. 

In some dogs, pseudo-pregnancy goes unnoticed, but in others, it is very noticeable and can be a reason for consultation. In general, this stage lasts two to three weeks. A female who manifests these signs once has a high chance of repeating them with every heat.


This stage lasts the longest (about four to five months). The anestrus period is also known as the resting stage, characterized by no signs of hormone-induced behavior or physiological changes during this phase. The dog’s heat cycle starts again after this stage.

11 Common Behaviors of a Female Dog In Heat

The more information you have about your female dog’s reproductive cycle, the more prepared you will be for the physical and behavioral changes that may occur. During each phase of the heat cycle, the canine will exhibit specific behaviors and physical signs.

Let’s look at the common behaviors of a female dog in heat:

Common Behaviors of a Female Dog in Heat 1 1 I Love Veterinary - Blog for Veterinarians, Vet Techs, Students

1. Bloody Discharge and Inflammation of the Vulva 

These are the two most noticeable signs of a dog in heat. Both are effects of estrogens during the proestrus phase and last approximately two weeks. The purpose is to attract the attention of males. 

The blood contains a substance called dog pheromones, which is irresistible to males. And the large size of the vulva has a visual effect on suitors. Once estrus begins, the bloody discharge becomes transparent and less thick until it disappears. 

Also, the swelling of the vulva decreases, thus allowing copulation.

2. Excessive Licking

The above changes make the female uncomfortable. Dogs don’t like to soil their territory. The dog constantly licking during the proestrus stage is to “clean” the blood they eliminate through the vulva. Besides, it is also a way to give themselves pleasure.

3. Change in Urination Habits 

A female dog in heat urinates more often than usual, lifts the leg, and only urinates a few droplets. In reality, females mark territory and ” call” the males with the pheromones eliminated in these tiny droplets deposited in as many places as possible.

These different urination habits occur during estrus when the unspayed dog is ready to copulate.

4. Getting Friendlier With Other Dogs

During estrus, the female allows male dogs to approach. She is attracted and receptive to “flirting”. When a male approaches, she wags her tail or holds it erect upwards as a sign of acceptance. The male may sniff and even lick the female’s vulva. This behavior is typical of courtship before copulation. 

During proestrus and diestrus, female dogs in heat don’t accept the male; in fact, they may become aggressive when approached by him.

5. Change in Posture and Tail Position

During proestrus, females don’t accept males and will tuck their tails between their legs if one approaches. When female dogs enter the estrus phase, they are ready to mate and show this by their posture and tail position. 

The unspayed dog will adopt a suggestive posture of invitation to male dogs. An immobilization reflex manifests; they raise their tail and move it to one side, exposing their genital area and presenting vulvar contractions. This reflex also appears when petting the dog in heat near the genital region.

6. Mounting and Humping

What does it mean when a female dog mounts a male? It is one of the most apparent signs of a female in heat. So, female dogs in heat mount, too. They may mount other females, males, objects, and even your leg as a sign that they are ready to mate.

7. Anxiety, Agitation, and Nesting

Female dogs can become hyperactive in heat. They try to escape from home to search for males. The urge to mate is powerful, and they may do incredible things like jump off a balcony, go through a fence, or scratch on a door until they get exhausted. 

They can be anxious and agitated if they do not manage to escape. After the end of the estrus and the beginning of the diestrus, they can prepare a nest to receive their babies. They usually adopt a quiet, dark area, such as under the bed or in a closet. 

8. Seeking out Male Dogs

As mentioned above, mating is an instinctive dog behavior. They will go to great lengths to achieve it. They will spend a great deal of energy and effort. And they can even be very skillful in doing so.

Some dogs achieve mating through a fence. Or petite males (Chihuahuas, for example) manage to mate with larger females (Cocker Spaniels, for example).

9. Reluctant Eating

A female dog in heat is not thinking about eating. All the energy goes into mating. At the end of the female’s hormonal cycle, she usually loses weight due to the energy expended in producing hormones. Searching for males means little interest in food during this period.

10. Mood Swings

The behavior of a female in heat depends a lot on each dog and its temperament. She can change her behavior in the different phases of the reproductive cycle. She can be aggressive, affectionate, lazy, or crazy.

11. Being More Vocal

As a consequence of hormones, Females in heat tend to be noisier. They cry most of the day in repeated attempts to call the males.

How Do You Take Care of A Dog in Heat?

Preventing your female dog in heat from getting pregnant is not as easy as it sounds. Do not underestimate your female dog’s determination to reproduce. It is necessary to be vigilant.


Sterilizing female dogs, which involves the removal of the ovaries and uterus, is the most common and effective method of preventing unwanted pregnancies and reducing overpopulation. Spaying is a permanent procedure.

Consider spaying your dog after her heat cycle (and not during) if you have no plans to breed your dog.


  • Always walk your dog on a leash while she is in heat. Even if she is a very obedient and well-trained animal, the power of hormones can be stronger. 
  • Do not frequent dog parks or other dog-populated areas while your dog is in heat. 
  • Ensure your dog has a current ID tag and a microchip with current data, or use a GPS dog tracker.
  • You can place some substance (such as a dog cologne or deodorant) on the tip of your dog’s tail to mask the smell of pheromones. It will decrease the possibility of the males detecting the scent of your in-heat dog.

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  • Never let your dog go out alone in the yard. Remember that dogs will make even the most unusual choices to mate.
  • You can create a limited space inside the house where the dog can roam and avoid staining all your furniture. Usually, this means restricting it to areas that are easy to clean, without carpets or high-end furniture.
  • Creating a nest for your dog to nap in with towels to catch the blood will help prevent accidents.
  • Use doggie diapers to prevent soiling: The first thing to clarify is that dog diapers will not protect your dog from the act of mating. Unneutered males are usually very determined and can manage to mate with a female in heat, even if she is wearing a diaper.

There are different dog diapers on the market: 

  1. Reusable diapers: An ecological and economical option.
  2. Disposable diapers: A quick and convenient solution.
  3. Full-body dog diapers: A good option for dogs with difficulty keeping their diapers on.

They are available in various sizes, from x-small to x-large. Proper sizing is essential to avoid leaks. If you decide to use a dog diaper, remember it should be waterproof, absorbent, and comfortable.

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  • IMPORTANT FUNCTION: For untrained pups or elderly dogs, it can be used to prevent urinary incontinence. For female dogs to use in menstrual periods, and for male dogs in heat. HEYWEAN doggie diapers provide a good solution for all above situations, prevent uncontrollable incontinence accidents or protect sexual harassment from male dogs.

Our Bonus Tips

  • Play more than usual with your dog to distract and tire her.
  • Give her dog treats that will serve as mental stimulation and games such as food dispensers that will keep her distracted for a long time.
  • Be patient; remember that hormones dominate her temperament these days.
  • If she is very anxious, you can create a calm environment inside the house, such as lowering the TV volume, using environmental pheromones (Adaptil), and playing relaxing music or TV for dogs.
  • Creating a healthy balance between exercise and rest is the key.
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Consult a Veterinarian

If you have doubts or feel something is wrong, do not hesitate to consult your veterinarian.

The Final Say

Understanding the typical behaviors exhibited by a female dog in heat equips you with the knowledge to recognize when your cherished companion is experiencing this natural phase, thereby enabling you to take preventive measures against unintended pregnancies. 

Additionally, it’s essential to bear in mind that opting for spaying is a responsible choice if breeding is not part of your plans. 

By taking proactive steps to care for your pet’s well-being, you contribute to creating a safer and healthier environment for both your beloved furry friend and the community at large.


Do Female Dogs Have Periods?

Female dogs do not experience menstruation like humans do. Instead, they go through estrus, characterized by bleeding from the vulva due to increased blood flow.

This bleeding occurs before, during, and shortly after ovulation, marking the end of the fertile period. It’s essential to understand this distinction and not refer to it as a “dog period.”

Do Dogs Get Period Cramps?

No, female dogs in heat do not suffer from colic or other pains because the bleeding comes from the vulva, not from the uterus, as in women.

Do Male Dogs Go Into Heat?

No, the estrus cycle is specific to females. Males do not have this reproductive cycle.

How Do Male Dogs Know Females Are in Heat?

Dogs have a developed sense of smell. The unsterilized male smells the pheromones eliminated in the vaginal secretions and urine of the unsterilized female.

At What Age Should I Spay My Female Dog?

Veterinarians advise spaying female dogs before their first heat, usually around six months old, to reduce the risk of mammary cancer to 0.5%. However, spaying before this age isn’t recommended as sex hormones affect growth.

Although early spaying can lead to increased urinary incontinence, the notion that female dogs need a litter before spaying is a myth.

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Alianna Munakata


Alianna has built a strong educational foundation to complement her extensive hands-on experience in the field of veterinary medicine. She holds a New Zealand National Certificate in Veterinary Nursing, which she earned from Otago Polytechnic in 2012. Furthermore, she graduated with a Bachelor of Veterinary Technology from Massey University, New Zealand, in 2015. Her commitment to expanding her knowledge is evident through her advanced qualifications in veterinary nursing, with a specific focus on reptiles and amphibians, small mammals, and the handling of venomous snakes.


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