Do you have a male or female dog, which has not yet been spayed or neutered? In this case, knowing the signs of a dog in heat is very important for both male and female dog parents. This can help you to do the following:

  • be better prepared for the experience
  • prevent unwanted pregnancy/new puppies
  • plan for puppies when you do want them
  • avoid dangerous situations; dogs in heat can be very unpredictable and even run away from home
  • keep track of your dog

So what are the most common symptoms of a dog in heat? What can you expect when your dog is in heat? Here are the answers to the most frequently asked questions on dogs in heat.

What does it mean when a dog is in heat?

A dog in heat refers to the time in a female dog’s life when she’s fertile and ready to breed. It’s the stage in a dog’s reproductive cycle when she’s ovulating, and therefore open to potential mates.

Watch out – during this time your dog may act funny, showcasing the classic symptoms of a dog in heat. And since she’s open to mating, there’s a real possibility that your dog could become pregnant during this time. So you may need to take action in order to prevent an unwanted dog pregnancy.

The dog in heat cycle is also known as the 4-stage estrus cycle in dogs.

Two dogs in heat playing together on a beach

When do dogs go into heat?

Female dogs have their first heat cycle when they reach puberty: the time when they become sexually mature and capable of reproducing. This usually happens around six months old, but the exact age can vary by breed.

Small dogs are known to start their estrus cycle earlier, whereas large or giant breeds may not have their first heat until they are 18 – 24 months1.

Heat and breeding in domesticated dogs can happen any time of year – they’re not associated with any particular season. The only exception is Basenjis and Tibetan Mastiffs, who tend to go into heat in spring.

Two dogs in a lawn fighting over a stuffed toy

How often do dogs go into heat?

On average female dogs go into heat twice a year, or about every six months. But the frequency and interval can vary between dogs and among different dogs breeds. For example, very large breeds may go into heat only one time a year, while small dog breeds may cycle three times per year.

Dogs typically have two heats per year, but each dog differs in length of heat, discharge amount and hormonal changes.

While a dog is still young, their heat cycle may be irregular. It can take up to two years for a dog’s heat cycle to become regular.

Do male dogs go into heat?

No, male dogs don’t go into heat – only a female dog can be in heat. Being ‘in heat’ specifically refers to the estrus stage of a female dog’s reproductive cycle, during which she’s receptive to mating and could therefore get pregnant.

While they don’t have a heat cycle, male dogs can mate all year round after reaching puberty at around 6 months old. If you have an uncastrated dog older than 6 months, you probably know the challenges that come with his sexual maturity. Constantly ready to mate, an unfixed male dog will mount things and run away at every chance he gets – eager to meet and “greet” the neighborhood bitches.

A male dog approaching a female dog in heat
pink triangle graphic with exclamation

Although male dogs don’t go into heat, keep in mind that the female dog in heat cycle can have a major impact on your male dog.

How do male dogs pick up on female dogs being in heat?

Male dogs will pick up the scent of female dogs in heat thanks to a special pheromone known as Methyl p-hydroxybenzoate. This smell can make your male dog crazy – especially if he’s intact, he’ll become sexually aroused and may put his entire focus on pursuing the female dog.

Mating is the ultimate goal of this natural, strong instinct in unneutered dogs. During this time it can be helpful to track your dog with a GPS dog tracker to make sure they stay out of trouble. (I.e., invading your neighbors’ yards to meet and greet their fertile female dogs.)

A big dog chasing a smaller dog outdoors

Your male dog might even neglect opportunities for food or water, since his instinct is very much focused on mating. Get some tips on how to persuade your dog to drink water in order to avoid dehydration.

Common behaviors of a female dog in heat

Not sure if your dog is in heat? Vaginal bleeding may be the first indicator that your dog is coming into heat. Here are a few common behaviors of a female dog in heat to watch out for, along with some other dog in heat symptoms:

1. Excessive licking

It’s normal for dogs to keep themselves clean and tidy by licking themselves. But if you notice your female unspayed dog licking her private parts excessively, it’s a good indication that she may be in heat!

A female dog will lick herself in response to the swelling of the vulva and bloody discharge she experiences as a part of her reproductive cycle. Most dogs can keep themselves clean during this time. If your dog’s discharge is making a mess, you may want to consider using heat diaper and/or dog wipes.

2. Change in urination habits

A female dog who is ready to mate often urinates differently, so that’s clue #2 that your dog is in heat. This could mean:

  • urinating more often than usual
  • raising her leg differently while urinating – or when she sees a male dog
  • frequently urinating around male dogs

So if your dog’s peeing habit is suddenly not as predictable as normal, she might be in heat.

two brown and white dogs sniffing each other in the grass

3. Getting more friendly with male dogs

Another big clue that your dog is in heat is when she starts to become more attractive and receptive to male dogs. She will likely be more friendly towards male dogs, while they also show increased interest in her.

For example, during heat she may let male dogs sniff and lick her vulva, when normally she would not tolerate this behavior. Excessive tail wagging is also a sign of openness towards male dogs, signaling that she welcomes physical contact.

4. Change in posture and tail position

When female dogs enter the estrus (second) phase of the dog in heat cycle, they’re ready to mate and they show this with their posture and tail position. Your dog make take a suggestive posture, as an invitation to male dogs. You’ll also see her raise her tail slightly and move it to the side – this position becoming even more pronounced when she’s touched.

5. Mounting and humping

When aroused, female dogs may mount, hump or thrust when they’re ready to mate – it’s not just male dogs. This is one of the most obvious signs of a dog in heat. She’ll mount or hump both male and female dogs, or other things she might mistake for a dog.

A dog may also become hyperactive while in heat. If you find your dog roaming in search of a mating partner – escaping from the backyard or pulling on the leash – a Tractive GPS Dog Tracker can help you track your runaway dog in real-time. (With just a glance at your phone.)

Now if your furry friend runs away, you can use the LIVE Tracking feature of the GPS tracker from the convenience of your smartphone and find your four-legged friend in no time. Which, like for this happy Tractive dog parent, turned out to be a lifesaver:

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Find Your Runaway Dog

6. Anxiety, agitation and nesting

Finally, a female dog in heat may become anxious or even aggressive during the time she’s open for mating. Commonly she’ll also display nesting behaviors, in preparation for pregnancy.

Of course, these are not all the possible signs of a dog in heat. Your dog might also become more affectionate towards you, become lazier or more aroused, show signs of distress or ease, or even run away. How a dog in heat will act depends a lot on the individual dog and their temperament.

pink triangle graphic with exclamation

In case your dog shows any warning signs of illness during her heat cycle, contact your veterinarian.

two dogs outside sniffing each other with leaves on the ground

4 stages of the dog heat cycle

To better understand the signs of a female dog in heat, it’s best to break down the various stages of the dog in heat cycle, also known as the estrus cycle in dogs. Below are the four stages that your unspayed female dog will cycle through:

1. Proestrus stage

The first stage of the dog heat cycle is called proestrus. This stage can last from 3 to 17 days, but many dogs experience about 9 days in proestrus. The first sign of this stage is the swelling of the vulva. This is one of the best ways to spot the beginning of a dog heat cycle. During the proestrus stage, you may notice the following symptoms:

A personality change:
Changes can range from quite mild to more severe. Sometimes a female dog will become more affectionate and clingy with her owner, other times she may seem a bit grumpy.
Appetite changes:
It’s not unusual for a dog to go off her food a bit during this first week, or she may get hungrier. Whatever the change is, taking note of it can be a significant clue that the heat cycle has begun.
Swelling of the vulva:
The amount of vulva swelling varies from dog to dog. Some dogs swell just a bit, while others swell quite a lot. Bleeding also varies, but typically bleeding is light during the first few days and grows a bit heavier mid-week.
Tail tucking:
This is a reaction to guard the vulva, either by tucking the tail between the leg or sitting down whenever another dog approaches.
The 4 stages of the dog in heat cycle - infographic by Tractive

2. Estrus Stage

The estrus stage typically last from 3-21 days and lasts 9 days on average. This is the time your dog is fertile (her actual heat) and where the ovaries begin to release eggs for fertilization. During this stage the female dog will be willing to accept male company. She will switch her tail to the side and she might try to be outside more often than normally. She is following her instinct to breed. During this period, symptoms include:

Lightened discharge:
Previously bright red, the discharge now lightens to be somewhat pink.
Softening of the vulva:
Initial swelling subsides just enough to make the vulva soften enough for penetration.
Whereas she previously tucked her tail to push away male company, she now begins to behave flirtatiously. E.g. inviting the male by turning her rear toward him and holding the tail high and out of the way.

3. Diestrus Stage

As diestrus takes over, the fertile part of the heat cycle comes to an end. This stage can last from 60-90 days and, at this point, the dog is no longer fertile. If the dog has been impregnated, the diestrus stage lasts from the end of the estrus until the birth of the puppies (around 60 days). Signs of the diestrus stage include:

Gradual disappearance of vulva swelling:
Most of the swelling is gone within one week’s time, but the vulva may remain slightly enlarged.
Less flirting:
Whether pregnant or not, the dog now lacks the conditions to mate and is no longer interested in flirting.

4. Anestrus Stage

Anestrus is the final stage of the dog heat cycle, also known as the resting stage. This is the longest phase of a dog’s heat cycle, from 100-150 days, at the end of which the entire heat cycle starts again.

How long does a dog stay in heat?

Female dogs in heat in the estrus phase of the heat cycle usually display the signs of heat for 3 – 21 days or 9 days on average. For more information see the detailed explanation above. Dogs will typically have two heats per year, but each dog differs in length of heat, discharge amount and hormonal changes.

young woman kneeled down petting a brown dog which is laying on the grass outside in a park

Do dogs have periods?

You might wonder: do female dogs have periods? Female dogs do bleed as a part of their reproductive cycle. But unlike human women who bleed about once a month, un-neutered female dogs bleed during the estrus phase of their cycle.

Dogs in heat will have a blood-tinted discharge along with a swollen vulva. The heat can last up to three weeks. The bloody discharge usually starts out dark in color, and gradually lightens over time.

Female dog diapers: Where they help, and where they do not

Female dogs are, similar to humans, usually very neat during their heat period. But this behavior varies from dog to dog. Some dogs will clean themselves meticulously, while others can be very neglectful. In the same way, the intensity of their bleeding can vary.

In case you’re having trouble with your dog’s spotting, you can consider using a dog diaper for the duration of your female dog’s heat. There are:

  • Reusable dog diapers: an eco-friendly and cost saving option, if you’re okay with washing your dog’s diapers
  • Disposable dog diapers: best for dog parents looking for a quick, convenient solution
  • Full body dog diapers: a good choice for dogs who have trouble keeping their diapers on

Of course, you need to give your dog time to get used to this first. You could start preparing your dog for the new clothing item, before the period kicks in.

Keep in mind: Dog diapers will not protect your female dog from the mating act! Uncastrated male dogs are usually very determined – and may succeed in mating with a female dog in heat even if she’s wearing a diaper.

How to handle a female dog in heat

1. Never let your dog out in the yard alone

Protect your dog from male dogs and unwanted pregnancy. Go out into the yard with your dog when she’s in heat. You might even consider using a leash.

2. Keep your dog on a leash during walks

Even if you consider your dog extremely well trained, walking off-leash is a “no-no” when your dog is in heat. No obedience training is as strong as natural instincts.

3. Balance between exercise and rest

Different dogs react differently to heat. Some may feel tired all day, while others may become restless. Observing your dog’s behavior and choosing the right amount of rest and exercise is important to keep your dog comfortable.

4. Consult a vet

Even though being in heat is not an illness, having a chat with your veterinarian about things to take care of during heat may help you if unexpected trouble occurs.

5. A scent-masking substance on the tip of her tail

When walking outdoors, applying a scent-masking substance (like a pet-safe cologne or deodorizer) can help hide the scent. It may become handy if a male dog suddenly appears nearby, so he does not detect your female in heat.

6. Use a GPS dog tracker

If a dog in heat suddenly runs away in search of a mate, a GPS dog tracker like Tractive will show you exactly where your dog is headed. That way you will quickly and easily find your female friend again and protect her from unwanted pregnancy.

For example, you could set up a “safe zone” (around your house or backyard) to monitor your dog’s movements while they’re still in it. Now the minute your dog tries to sneak out, you get an instant escape alert on your phone. (So you can intervene and prevent them from wandering.)

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Track Your Dog With Tractive

The dog mating process explained

This following infographic illustrates the act of sex or mating between two dogs.  The different stages and duration of the dog mating process are as follows:

  1. First Stage Coitus (approximately 2 minutes)
  2. The Turn (approx. 5 seconds)
  3. Second Stage Coitus (5-45 minutes)

First, the male dog will sit on the female dog (first state coitus). Should they keep this initial position, they would suffer from severe cramps. For this reason, they will change positions (the turn), and the dogs will continue mating (second stage coitus) as illustrated in the infographic below. The uterus, vagina, bulb, vulva and penis are all involved in the sexual act between dogs.

dog in heat mating process explained

One of the main takeaways from the infographic is the fact that it is forbidden to separate dogs during the mating act, since this can lead to serious consequences.

The mating act: Am I allowed to separate dogs while mating?

There is a clear answer to this: NO, under no circumstances! You can easily harm both dogs. (Since the limb of your dog is swelling, while the muscles of your female dog are contracted.)

The mating act should not be mistaken as a light encounter. This process can last up to 30 minutes and might often look embarrassing for humans.

Top tips for handling a dog in heat

Dogs and menopause: Is this a real topic?

Your female dog is fertile until the end. A missed heat period can be a sign of illness in dogs. Should you notice this happening, make sure to pay your vet a visit.

Undesired dog pregnancy? Your available options

Despite all tips and measures, your furry friend could become pregnant. Here are your options, in case of an unplanned dog pregnancy:

  • Abortion shot: This option is not without risks and should be only used in extreme emergency cases.
  • Hormonal suppression: With this treatment, one can provoke various uterus illnesses to the female dog. Should this option be the only way, your vet is only allowed to give the shot during the hormonal pause period. (In order not to harm your dog’s uterus.)
  • Spaying the female before the puppies come to full-term.

And finally…

If you think your dog may be going into heat soon, tracking them in real-time can be a lifesaver. A particularly motivated dog can travel several miles away from home in search of the perfect mate. And there’s always the risk they might be hit by a car, attacked by another pet or person, eat something that’s off-limits for them…the list goes on.

So invest in a dedicated pet GPS tracker for your dog in heat – and never worry about losing them ever again.

packaging of the Tractive GPS DOG tracker

Always know where your dog is

Follow every step in real-time with unlimited range. Get alerts if they wander too far. Keep them happy & healthy with Wellness Monitoring. And let others – like walkers or sitters – keep an eye on your dog too.

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For more insights on female dogs in heat, check out the video below:

And if you’ve found this post helpful, then share it with a fellow dog parent – and let’s help build a safer world for our furry friends, together.

Your furry friend’s health and wellbeing means as much as to us as it does to you. So we’ve made it a priority to only share medically-relevant content on our blog.

This post was checked, double-checked, and medically verified by Georgia-based vet, Dr. Dwight Alleyne.

Dr. Dwight Alleyne, DVM

Dwight Alleyne was born and raised in Long Island, New York where his love of animals began. His career for animals began working for a well-known no-kill animal shelter on Long Island.

Dr. Dwight Alleyne, DVM

He worked his way up the career ladder working as a kennel technician, veterinary assistant, and then becoming a licensed veterinary technician at the shelter.

His passion for veterinary medicine led to him applying to and being accepted at Cornell University Veterinary where he graduated from in 2006. After completing a small animal rotating internship at Purdue University, he eventually made his way to Georgia where he has been practicing ever since.

Dr. Alleyne has practiced at several small animal clinics throughout Georgia. He has a keen interest in soft tissue surgery and has extensive experience in performing ultrasounds including echocardiograms.

When he is not practicing medicine, Dr. Alleyne enjoys writing and editing pet health articles and providing pet advice through telehealth.

Dr. Alleyne also has his own blog called “The Animal Doctor Blog.” Check it out on: