4 Ways to Tell if Your Dog Is in Heat

If your usually chill pup is suddenly peeing every five minutes, flirting with every male dog in a one-mile radius, and obsessively grooming her back end, you might be wondering: “Is my dog in heat, or is she just being dramatic?” Good news: there are clear ways to tell, and once you understand your dog’s heat cycle, the whole thing feels a lot less mysterious (and a lot less stressful for both of you).

This guide breaks down four practical ways to tell if your dog is in heat, what’s normal, what’s not, and how to keep her safe and comfortable through it all.

First, a Quick Look at the Dog Heat Cycle

Female dogs don’t have monthly periods the way humans do. Instead, they go through an estrous cycle (commonly called “heat”) typically about twice a year, though the timing varies by dog and breed. Many females have their first heat between 6 and 24 months old: smaller breeds tend to start earlier, while giant breeds may not cycle until they’re closer to two years.

The cycle has four stages:

• Proestrus: The “getting ready” stage, usually about a week or so. You’ll see vulvar swelling and a bloody discharge, but the dog isn’t usually receptive to mating yet.
• Estrus: This is the true “in heat” phase. Discharge lightens in color, and the dog becomes receptive to males.
• Diestrus: The post-heat stage, whether she got pregnant or not. Hormones shift, and the vulva and behavior gradually return to normal.
• Anestrus: The quiet resting phase between cycles when nothing much appears to be happening on the outside.

For most dogs, a full heat lasts about two to four weeks from the first spotting until everything settles back down.

Way 1: Spot the Physical Changes

The easiest way to tell if your dog is in heat is to pay attention to her body. A few physical changes are classic signs of a dog entering or actively in heat.

1. Swollen vulva

One of the very first signs is a swollen, puffy vulva. The area becomes larger and more prominent than usual, often with a slightly shiny appearance. This swelling can begin a few days before you notice any discharge.

2. Bloody or pink discharge

Next comes the discharge. At the start of heat (proestrus), it’s usually bright red and blood-tinged. As your dog enters the fertile estrus phase, it often becomes lighter, turning pinkish or a straw color. Many dogs are very clean and will lick away much of the discharge, so you might only notice faint spots on bedding, the floor, or her fur.

3. Increased licking and grooming

Most females will lick their vulva more often during heat to keep themselves clean. Occasional licking is normal; constant, frantic lickingespecially paired with foul-smelling discharge or obvious paindeserves a vet visit.

4. More frequent urination

When a female dog is in heat, her urine carries a chemical “announcement” to male dogs that she’s in season. She may start urinating more frequently or leaving small “messages” on walks, fence posts, and even inside the house. This isn’t bad mannersit’s biology.

If you’re seeing a combination of swelling, discharge, and extra pee breaks, you’re very likely looking at a dog in heat rather than a random bladder issue. Still, if your dog strains to urinate, seems painful, or passes only a few drops at a time, call your vet to rule out a urinary infection.

Way 2: Watch for Behavioral Changes

Heat doesn’t just show up on the outside. Hormones are busy behind the scenes, and they can shift your dog’s mood and behavior in surprising ways.

1. Clingy, restless, or moody behavior

Some dogs become extra affectionate and clingy, following you from room to room and insisting on cuddles. Others get restless and pace, whine, or seem distracted. You might notice your calm couch potato suddenly has nervous energy, or your independent girl transforms into a Velcro dog.

2. Flirting and “flagging” the tail

During estrus, many females start to “flirt” with males. They may:

• Turn their rear toward male dogs
• Hold the tail to one side (called flagging)
• Arch their back if you pet near the tail

These behaviors are your dog’s way of saying, “Yes, I’m available,” even if you are absolutely not on board with that plan.

3. Mounting, humping, and new social drama

Mounting isn’t just a male habit. A female in heat may mount other dogs, toys, or even pillows. Some dogs also get a little snappy with other females or feel more easily annoyed by housemates.

Individually, any of these behaviors could have other causes, but when they show up alongside the physical signs, they strongly point toward a heat cycle.

Way 3: Notice How Other Dogs React

Sometimes the first clue that your dog is in heat is the behavior of other dogsespecially males in the neighborhood.

• Male dogs become obsessed. They may whine at your fence, pace outside your house, try to follow you on walks, or suddenly “forget” every command they’ve ever learned.
• Dogs at the park pay extra attention. Off-leash males might swarm around your female, sniff intensely, or attempt to mount her, even if she normally isn’t the star of the show.
• Male dogs travel impressive distances. Some can smell a female in heat from far away and will do everything in their power to get to her.

If male dogs are acting like your girl is a celebrity, chances are she’s giving off heat-related pheromones, even if her own signs look mild.

Way 4: Track Timing and Patterns

A huge part of recognizing heat is knowing your dog’s normal schedule. Once your dog has had one or two cycles, you can usually predict when the next one might show up.

1. Keep a simple heat diary

On your phone or in a notebook, jot down:

• The first day you notice swelling or discharge
• Any big behavior changes
• The day her vulva and behavior seem back to normal

Over time, you’ll see a pattern: many females cycle roughly every five to seven months, though some breeds and individuals are less predictable.

2. Watch for “silent” or subtle heats

Not all dogs show dramatic signs. A “silent heat” is when outward signs are mildvery little discharge, minimal swellingbut the dog is still fertile. This is another reason tracking timing matters. If your dog’s behavior and cycles line up with heat, assume she could be fertile, even if you don’t see textbook symptoms.

3. When timing seems off

Contact your vet if:

• Your dog hasn’t had a first heat by about two years of age
• She suddenly stops cycling for more than a year
• Her heats are extremely frequent or unusually prolonged

Irregular cycles can sometimes be normal, especially early on, but they can also point to underlying health or hormonal issues that deserve a professional look.

Is It Heator Something More Serious?

Heat is normal. But certain symptoms that look a bit like heat can signal medical problems instead.

Call your veterinarian right away if you notice:

• Very foul-smelling or thick, pus-like discharge
• Severe lethargy, vomiting, or loss of appetite
• Extreme thirst and frequent urination not explained by heat alone
• Straining to urinate, crying when urinating, or blood in urine only

These can be signs of infections such as pyometra (a dangerous uterine infection) or urinary tract issues, which require prompt treatment. When in doubt, it’s always safer to have your vet take a look.

How to Care for a Dog in Heat

Once you’ve confirmed your dog is in heat, your job is part bodyguard, part housekeeper, and part emotional support human.

1. Prevent surprise puppies

• Keep your dog indoors or in a secure, fenced yardno unsupervised outdoor time.
• Avoid dog parks and off-leash play with intact males.
• Check your fence and gates for escape routes. A determined male (or female!) is shockingly motivated.

2. Manage messes comfortably

You can use dog diapers or washable heat pants to catch discharge inside the house. Make sure they fit well and change them frequently so your dog stays clean and comfortable. Provide washable blankets or throws on her favorite furniture for easy cleanup.

3. Support her emotionally and physically

• Offer a quiet safe spot where she can rest away from other pets.
• Stick to calm walks on leash instead of high-energy dog social events.
• Use puzzle toys or gentle training sessions to help channel extra nervous energy.

Most dogs feel a bit “off,” but not miserable, during heat. If your dog seems very distressed, painful, or completely unlike herself, schedule a vet visit.

4. Talk to your vet about spaying

If you’re not planning to breed your dog responsibly, spaying is usually the healthiest long-term choice. It prevents future heats, eliminates the risk of pyometra, and greatly reduces the risk of certain reproductive cancers later in life. Your vet can recommend the best timing based on your dog’s age, breed, and overall health.

Common Myths About Dogs in Heat

Myth 1: “Male dogs go into heat too.”

Only female dogs go into heat. Male dogs reach sexual maturity around six months and can mate year-round; they don’t cycle the way females do.

Myth 2: “Every female dog should have one litter.”

There’s no medical benefit to letting a dog have a litter “for her health.” In fact, avoiding pregnancy and spaying at an appropriate time generally lowers health risks over her life.

Myth 3: “If there’s no discharge, she can’t be in heat.”

Remember those “silent” heats. Some dogs keep themselves so clean that you rarely see spotting. Timing, behavior, and the reactions of other dogs matter just as much as visible blood.

Real-Life Experiences: What Heat Looks Like in Everyday Homes

Heat cycles don’t just happen in textbooks; they happen in real kitchens, living rooms, and backyardsusually when you just bought a new white rug. Here are some experience-based insights that many dog owners discover the hard way (so you don’t have to).

Molly the Golden Retriever: The Surprise First Heat

Molly’s family thought they had at least a few more months before her first heat. One morning they woke up to tiny red spots on the tile floor and assumed she’d cut her paw. Only after checking her feet, bedding, and the rest of the house did they notice her vulva was enlarged and she was licking herself more than usual. Their takeaway? Do a quick body check whenever something seems “off.” A fast once-over made it clear nothing was injuredshe was simply starting proestrus.

They immediately started a “heat calendar” on their phones, blocked the backyard fence where a friendly neighborhood male had been visiting, and picked up a couple of washable diapers. By her second heat, they felt much more prepared and far less stressed.

Luna the Husky: The Escape Artist

Luna was usually trustworthy off-leash in her fenced yard. During heat, though, she became laser-focused on finding male dogs. On one memorable afternoon, she climbed a four-foot fencewith zero practicebecause a male dog was pacing on the other side.

Her owner’s new rule: never underestimate a dog in heat. A dog who has never dug, climbed, or squeezed through a barrier before may suddenly get very creative. Now, during Luna’s cycles, she only goes outside on a leash or in a securely supervised area. The family also added taller fencing and checked for gaps along the bottom of the fence line.

Hazel the Rescue Mix: The Silent Heat Detective Story

Hazel’s signs were subtle. No obvious spotting, minimal swelling, and only a slight change in appetite. What gave her away was the behavior of a usually calm male dog next door. He began whining at the fence, pacing, and trying to dig underneath it. Hazel also started pausing on walks, holding her tail slightly to the side when other dogs approached.

Her family learned that other dogs can be your early-warning system. If intact males suddenly act like your dog is the hottest celebrity in town, assume she may be in heateven if you don’t see much discharge. From then on, they scheduled vet checkups to discuss spaying and used that timing information to predict future cycles.

Juggling Daily Life During Heat

Many owners also find that planning ahead makes each heat smoother:

• Adjust your cleaning routine. Keep pet-safe wipes handy, use washable throws on furniture, and choose darker bedding during heat cycles.
• Plan walks strategically. Early morning or late-night walks tend to be quieter, with fewer off-leash dogs around.
• Communicate with neighbors. Let neighbors with intact male dogs know your female is in heat so they can secure their dogs too.

Over time, most owners go from feeling blindsided by the first cycle to treating heat like any other routine part of dog carelike nail trimming or flea prevention. The more you observe your dog and note her patterns, the more confident you’ll feel.

When in Doubt, Call Your Vet

Heat is a normal, healthy process for intact female dogs, but it can definitely feel overwhelming the first few times. By watching for physical changes, behavior shifts, the reactions of other dogs, and the timing of her cycles, you can confidently tell when your dog is in heat and keep her safe through it.

If something doesn’t look rightdischarge seems unusual, your dog appears sick, or her cycles are very irregularyour veterinarian is your best ally. A quick call or exam can distinguish normal heat from problems that need treatment and help you decide whether and when spaying is right for your dog.