What Does It Mean If My Dog Is in Heat?
When female dogs go into heat, they’re entering estrus, the stage in their reproductive cycle when they can become pregnant. Depending on the size of your dog, heat can begin when they’re anywhere from 6 to 24 months old. In general, the smaller the dog, the sooner they go into heat.
A dog’s first heat cycle normally lasts between 3 and 4 weeks. After a dog has entered heat for the first time, it then occurs every 4 to 8 months, or about twice a year. Some dogs enter heat in a consistent time frame, while others’ cycles may vary; neither is usually a sign of larger health concerns. If your dog starts to show signs of entering heat a month or two after just going through heat, however, it could be a sign of a health issue that your vet should check out.
4 Signs Your Dog Is Going into Heat
The most frequent symptoms before heat include:
1. Swollen Vulva
Located just below the anus, your dog’s vulva will turn redder in color and increase in size — often 2 to 3 times its normal size.
2. Behavior Quirks
A dog entering heat can become more skittish or aggressive around others, including people and animals but especially other dogs.
3. Increased Licking of the Vaginal Area
While almost all dogs occasionally lick themselves in this area, you may see it much more frequently before they go into heat.
4. Vaginal Bleeding
If you notice bloodstains near or around areas where your dog rests, it’s likely your dog is in proestrus and the heat phase is about to begin. Dogs may bleed for up to 10 days during this phase.
4 Signs Your Dog Is in Heat
Once your dog is in heat, you may notice physical and behavioral changes, and changes in how other dogs behave around her. Here are the most frequent signs your dog is in heat.
1. Decrease in Vaginal Bleeding
The amount of blood typically decreases when your dog is in peak heat. Once this occurs, your dog is in the most fertile stage of estrus for about a week to 10 days, until bleeding starts again (although bleeding doesn’t always recur).
2. Mating Behavior
When your dog is around other dogs (both male and female), her behavior will be noticeably different. This may include mounting other dogs or letting herself be mounted. If no other dogs are around, your dog might try to mount your legs.
3. Switched Tail Position
Once she is fully in heat, your dog’s tail will often move or curl to the side. This is known as flagging and lets male dogs know she is ready and available for mating.
4. Male Dogs React Differently
If you have male dogs in your household or come across one on a walk, they’ll react differently to your dog in heat. This could include aggression toward other male dogs or increased barking and whining. They may also show much greater interest in your dog’s genital area.