When I was a teenager, my female dog, Lizzy, had strange behavior now and again. She would become timid, all the male dogs would pay more attention, and she would bleed from her vulva. I didn’t understand it then, but she was actually going into heat.
On average, a female dog can go into heat at six months of age for the first time. This is the average, though; some dogs can experience their first heat cycle anywhere between 4 months and two years of age.
From then on, if a female dog does not get pregnant, she can go into heat 2-3 times per year. On average, a female dog goes into her heat cycle twice a year, but it may even happen three times yearly for some breeds.
Keep in mind that a dog that has been spayed (fixed) won’t go into her heat cycles anymore. That’s because a spayed dog no longer has ovaries that produce hormones. And if she no longer has hormones prompting her to go into heat, such as estrogen, her cycles will stop.
To summarise: on average, a female dog will go into heat
- At six months of age for the first time, then
- Twice a year after that if she’s not spayed.
What are the Signs Your Dog is Going Into Heat?
If you’re new to this whole dog-in-heat situation, like I was at 13, your dog’s body will give specific signals to tell you she’s in heat. So, you don’t have to be a scientist to figure it out. Your dog’s body and behavior will tell you.
You will know your dog is in heat when some or all of the following happens:
- She has a swollen vulva
- There’s a bloody or light yellow discharge coming from the vulva
- Her appetite changes
- She pays more attention to the male dogs around her
- She tries to hide from male dogs
- Shel licks her genital area a lot
- She seems nervous or agitated
- She is more aggressive than usual
- She urinates more frequently
- Her tail position changes
When you see these signs, don’t worry. It’s a natural experience in all-female dogs that aren’t spayed. These signs should last anywhere from 2-4 weeks but can differ from dog to dog.
Now, you might be asking what all of these signs mean. Let’s take a closer look at each to understand your furry best friend better.
Swollen Vulva
Part of a dog’s heat cycle is that the ovaries produce more estrogen, which causes the vulva to swell. When the dog’s heat cycle is over, the vulva should return to its usual size.
The vulva swells in preparation to mate with a male dog. As the vulva swells, the tissue becomes softer, making mating easier.
What is the vulva? “The outer portion of a female dog’s reproductive tract is called the vulva. It consists of two labia (thick folds of tissue) that are connected at the top and bottom”
PetMD
So, a swollen vulva is how the female dog’s body prepares for mating, making the body more receptive to a male dog.
Discharge from the Vulva
The first time my Lizzy went into heat, I was disgusted by the discharge from her vulva. Again, I didn’t understand the natural changes a female dog’s body would undergo when she enters her heat cycle!
A female dog can bleed or have yellowish discharge coming from the opening of the vulva. The discharge contains pheromones which will arouse the male dogs around her.
What are pheromones? Pheromones are specific scent-chemicals produced by a female dog in heat and are found in the vulva’s discharge. This scent is so strong that male dogs can smell it three miles away.
Pawsperspective
The bleeding or discharge happens at the beginning of the heat cycle. The female dog will start attracting male dogs through feromones, but she won’t allow them to mate with her. Her body will let her know when to allow a male to mount her.
Change in Appetite
Dogs in heat usually eat less than usual or seem disinterested in food. This behavior usually concerns dog owners, but you don’t have to worry.
If your female dog in heat is not eating, it is because of the hormone changes in her body. Because of all the hormone changes, a dog in heat can experience a change in appetite. She can eat more than or doesn’t want to eat as much as usual.
As a dog goes into a heat cycle, her body produces an influx of hormones like estrogen, progesterone, estradiol, luteinizing hormone, and follicle-stimulating hormone. These hormones combined can affect her appetite, mood, and behavior.
This hormone influx also takes the dog’s primary focus away from everyday priorities like eating and sleeping and focuses more on the mating season she’s in.
Pay More Attention to Male Dogs
If you’ve ever experienced a dog in heat, you might have noticed that male dogs suddenly pay more attention to her. These male dogs might even change their own behavior in response.
A male dog pays more attention to a female dog in heat because of the pheromones she produces and can smell pheromones from up to 3 miles away.
In response to these potent pheromones, a male dog not only pays more attention to the female dog in heat, but his behavior can also change in the following ways:
- Become obsessed with the female dog in heat
- Eat less or stop eating at all
- Start to mark their territory more than usual
- Become more aggressive than usual
- Become restless
These behaviors are nature’s way of preparing a male and female dog to mate. However, if you don’t want your female dog to have puppies, keep her away from males that have not been neutered.
Hide from Male Dogs
Some female dogs in heat would try to hide from male dogs. Her hormonal changes can make her more clingy or have the opposite effect.
Some female dogs in heat would try to hide from all the excitement. It’s a tiring experience, and hiding might be the only way she can get some rest.
Licking the Genital Area Excessively
Most dog owners with unspayed female dogs know that the dogs lick their genital area more excessively and frequently. It’s an unmissable habit that almost seems unsanitary to most people. However, it’s a beautiful natural behavior of a dog in heat.
Dogs in heat will lick their genital area excessively as a hygiene practice. Whether male or female, all dogs have a natural cleanliness level. So. because they have discharge or blood coming from the vulva, they want to keep themselves clean.
Agitated or Nervous
Most dogs in heat may appear anxious or nervous during this time. Remember that being in heat is essentially the dog’s period and comes with loads of hormonal changes. These hormones can mess with the poor dog’s head.
A dog in heat may appear anxious or nervous because she doesn’t know what’s happening inside her body. These sudden changes can leave her body and mind feeling different, prompting a behavior change.
Think about it. Human teenage girls get their period, and they’re practically anxious, nervous, complex little creatures (I know because I was one of them). We didn’t know what to do with all these hormones swimming around in our bodies.
The same goes for female dogs in heat.
Aggressive Behavior
Again, the hormonal changes in a female dog’s body when in heat are a shock to the poor dog’s system. She is experiencing nervousness, but she can be irritable as well. Some dogs in heat can become aggressive, even if they weren’t aggressive ever before.
A dog in heat is prone to be more aggressive because of hormonal changes’ confusion, nervousness, and irritability.
It’s not the first mood change, though. These dogs are usually first nervous or anxious. Then they become irritable, then the aggression steps in if something pushes them past their tolerance levels.
Urinating More Frequently
Female dogs in heat might urinate more than they usually do. Not even that, but they do it everywhere they’re not supposed to. It’s as if they leave their house training manners at the door and follow a different set of rules: Mother Nature’s.
Dogs in heat urinate more frequently because they want to lure male dogs with pheromones. Like the discharge from the vulva, the urine also contains many pheromones. It’s an instinctual behavior, and the female dog doesn’t necessarily have that much control over it.
Tail Position Changes
Some might not notice that a female dog’s tail position changes during her heat cycle. Others might see their dog’s tail moving to one side, exposing her vulva.
A female dog might shift her tail toward the side to show male dogs she’s open to mating. This shift in tail position is called flagging. It’s the female’s way of showing male dogs she’s in the correct cycle time window to be receptive to males.
How Many Times a Year is a Dog in Heat?
After experiencing Lizzy’s first heat cycle, my teenage brain thought, “how often are we supposed to deal with this?” Surprisingly, it wasn’t as often as I was afraid to. It’s a lot of work for a teenage girl to manage school and these behavioral changes, you know?
An unspayed female dog will go into heat twice a year (every six months). But this number can vary depending on the dog’s size.
| Dog Breed Type | Number of Heat Cycles Per Year |
| Smaller breed dogs | 2-3 times per year (every 4-6 months) |
| Medium and large breed dogs | Twice a year (every six months) |
| Giant breed dogs | Once a year (every 12 months) |
So, don’t worry if your chihuahua goes into heat more than the average twice a year (as I’ve mentioned early in the article); it’s not uncommon for smaller dogs. On the other hand, don’t be surprised if your giant Great Dane only goes into heat once a year.
These are just guidelines; your dog’s heat cycle can vary even from other dogs her size or breed. Also, keep in mind that each dog’s body is different. Some might not have a reproductive system that fits the norm. So, slight variations from averages can be expected.
How Long Does a Dog in Heat Bleed?
As a dog parent with an unspayed female dog, you might get tired of the pesky bloodstains all over the house when she goes into heat. Although she tries to clean herself, it’s often not enough to prevent stains on your carpet, couch, bed sheets, or clothing. So, it’s good to know how long this bleeding will continue so you can be better prepared, right?
A female dog in heat can bleed for 7-10 days. It happens in the beginning stage of her heat cycle and luckily doesn’t last the whole duration.
The Paws Perspective
If you’re reading this article, you probably have a female dog or know of one in her heat cycle. I’ve been there, and it can be a nightmare. But, I would like to encourage you to still handle your furry best friend with all the love and patience in your heart.
Remember, she probably has no clue what’s happening with her or how to cope with these instinctual behavioral changes. So, please, be patient and supportive while she goes through this.
I’m not trying to be insensitive here, but if you’re thinking of breeding with your dog (if you’re not a registered breeder), please reconsider! Having puppies is a fantastic experience filled with cuteness, but sadly, many dogs in rescue shelters need forever homes.
It’s a common misconception that a female dog should have puppies at least once! All it does is create more dogs than the world’s society can give homes for, leaving more in shelters
Juan’ri from paws perspective