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17 Reasons Why Dogs (Suddenly) Act Crazy + Dangers & Tips

Why Is My Dog Acting Crazy

The world’s gone mad.

You’re going insane because your dog’s acting crazy lately.


Looks like someone needs help.

Don’t worry. In this article you’ll discover:

  • When you should visit a vet.
  • 23 scenarios of dogs acting weird.
  • 17 reasons why your pooch acts crazy suddenly.
  • What you should do to stop your dog from acting out.
  • And much much more…

Why is my dog acting crazy (all of a sudden)?

Your dog’s acting crazy because they’re getting stressed by a certain situation or from having physical pains. Therefore to relieve themselves, they’ll do unusual behaviors. This is a normal reaction for dogs whenever they get overwhelmed. 

17 reasons why your dog (suddenly) acts crazy

#1: It’s a ‘normal’ dog breed behavior

Dogs have different personalities. 

There are certain dog breeds that like to do activities normal dogs don’t usually do.

Take a look at the German Shepherds. They’re known as a herding breed. 

So there may be times when they’ll walk in circles around you – like they’re attempting to ‘herd’ you. 

Another example are the Huskies. 

They’re very active pooches who enjoy howling and running as fast as they can. 

These breeds may behave in a certain way according to how they’re raised and their breeding. 

And because of that, we misunderstand them as if they’re ‘acting crazy’. 

#2: Anal problems

Your Dog's Acting Crazy Due To Anal Problems

“My butt’s killing me. Help me, mama!”

You panic as you look at your pooch run like crazy and then scratch their butts on the grass. 

What’s happening?

According to PetMD, your dog is behaving this way because they might be having:

  • Worms.
  • Tumors.
  • Skin allergies.
  • Impacted anal sacs.

Dogs scoot their butts to relieve themselves of itch. But if they do this excessively, you should have your pooch checked.

#3: Food poisoning

When dogs eat human foods they’re not supposed to eat, they’ll act crazy. And in more serious cases, this can even lead to their death.

So what are the foods dogs aren’t allowed to eat? Here are some of them:

  • Avocado.
  • Chocolates.
  • Onion and garlic.
  • Macadamia nuts.
  • Grapes and raisins.
  • Caffeine such as coffee.

“Oh, no! 

What will happen if my dog accidentally eats these things?”

Dogs who have consumed the foods mentioned above may experience food poisoning. You should be on the lookout for the following symptoms such as:

  • Tremors.
  • Diarrhea.
  • Convulsions.
  • Excessive drooling.
  • Difficulty in breathing.

#4: Sudden changes in their environment

Children throw tantrums whenever they’re scared. 

If they change their house or school, they’ll cry or throw a fit because they’re nervous and uncertain.

Your dog’s just like that.

They may also feel uncertain if there’s a recent change in their surroundings. Like a new dog, a member of the family, or a new sleeping arrangement. 

Now, if your dog can’t cope, they’ll become so stressed that they’ll begin to act crazy. 

They’ll do unusual activities for comfort. 

Your pooch may chew on furniture, eat random stuff, and develop weird habits.

#5: Over-arousal

Oh, this doesn’t mean being aroused sexually

Over-arousal pertains to being overly excited or active. 

Aroused dogs have that happy look. Their eyes are bright like a star with their tongues sticking out.

They’ll also jump around, pant, spin in circles, and run back and forth. It’ll be impossible to make them settle down. 

The body of an aroused pooch will also get shaky. And their heart rate will get high.


What’s the cause of this again?”

The answer is too much sugar in their diet. This causes their blood glucose level to increase, making them hyperactive. 

#6: They’re territorial

Whenever you have a visitor, your dog acts crazy. 

They jump on them, chase them around, and bite on their coats. 

And because your guest’s scared out of their wits, they decided to leave your house pronto.

“Now, this is why we don’t get visitors!”, you tell your dog. 

The reason why your dog behaves this way is because they’re being territorial. 

Although this trait is common in dogs, you must still be cautious. 

Correct this behavior asap

Your pooch can become aggressive and dangerous in the long run. Not only to your visitors but to you as well. 

#7: Aggression

Your Dog's Acting Crazy Due To Aggressive Behavior

Your dog snarls, growls, and snaps at you. 


Looks like you’ve got an aggressive dog. 

Be careful with dealing with them, though. As mentioned earlier, they can become dangerous if their behavior isn’t corrected. 

So what causes a dog to become this way? 

There could be certain triggers why your dog will suddenly act crazy aggressive. 

It may be whenever they see strangers or when they cross paths with other dogs.

#8: Hyperkinesis

First things first. 

Hyperkinesis isn’t the same as being hyperactive and aroused.

Sure, these conditions make your dog impulsive. 

And they give your pooch high levels of energy that make them act a little bit crazy.

But Hyperkinesis is a more serious condition. This can also cause your dog to:

#9: Pica

Your dog’s been acting crazy. They’re always vomiting too.

One time, you caught them doing something behind your back.

They’re eating dirt and rocks. 

By the look of how fast they’re eating them, it seems like they’re doing it for a long time.


Seems like your dog has Pica, a compulsive eating disorder. 

This makes your dog eat non-edible items. Like rocks, dirt, socks, and even poop (their own and other animal’s stools too).

It’s a medical condition that’s often caused by nutritional deficiency, stress, and internal parasites.

#10: Dog dementia

Your lovable dog has changed. 

They’ve become grumpier. They snap at you, bark at imaginary things, pace in circles, and they poop around the house

Why’s your sweet pooch acting crazy?

Your dog may be having symptoms of Canine Cognitive Dysfunction, a.k.a dog dementia. 

It’s a brain degenerative condition that usually occurs in older dogs. This makes them do unusual things they didn’t do before.

#11: They don’t go out enough

Dogs who have nothing to do lash out by acting crazy. 

That’s because they’re meant to run around and play in wide spaces. 

And when they get cooped up inside the house for a long time, your dog will misbehave

They may get cranky if I must say. 

And because they have all this energy in their body, they try to expel it all out once they’re outdoors. 

This makes dogs difficult to walk. As they’ll pull on their leash to try to get in every direction all at once.

Check out: 7 Reasons Why Your Dog Walks In Front Of You + 5 Tips

#12: To burn off excess energy

You just run around the whole neighborhood with your dog. 

Even climbed half a hill. 

“So why the frig is my dog still acting crazy before sleeping?”

Oh, it looks like your pooch is burning off their excess energy!

Nothing to worry about here, dear. This one’s normal in all dogs.

When they’re too tired, dogs like to burn off every last bit of the remaining energy they have left.

Try to think of it as a kid who cries before they go to sleep. Get what I mean? 🙂

#13: Zoomies

Have you ever seen your dog run like crazy? And sometimes they do it in circles, too?

Look at how these pooches go!

This is called the zoomies. 

It’s the sudden bursts of energy your dog experiences whenever they’re too excited. 

For example, if you let them out of their crate, they’ll get the zoomies because they’re excited to go out. 

It’s like having all this energy pent-up, and your pooch is waiting to unleash it in just one go. 

Read further: 13 Reasons Why Your Dog Walks in Circles Around You + Tips

#14: High-level stress

Your pooch will also act crazy whenever they’re in a very stressful situation.

If they came from a vet, or after you took them for a bath, your dog can also get the zoomies. 

The reason for this is that they get anxious. And the only way to relieve themselves of their stress is by running. 

Well, it’s possible that they do this because they’re trying to escape from you too. 

Just kidding!

#15: Fear of sudden noises

Every New Year’s Eve and July the 4th, you prepare yourself. 

“It’s gonna be a long night!”, you tell your pooch.

These times of the year are when your dog acts like craazzzzyyy.

They tremble, whine, howl, and bark non-stop.

What’s the reason behind this? 

Dogs have sensitive ears. Their hearing capability is so much louder compared to us humans. 

Therefore, the sound of fireworks, vacuum, drilling, thunderstorms, and other loud noises are deafening to them. 

They get scared. And some dogs may even develop phobias from them. 

Read next: 9 Reasons Why Your Dog Climbs On Your Shoulders + 3 Tips

#16: Body pain or injury

Your dog’s limping around and whimpering. And when you try to touch or carry them, they growl and snap at you.

Oh, my!

It looks like your poor pooch’s in pain. 

In this case, you have to take them them checked-up at once. 

#17: Crazy’s funny

Your pup barks at their reflection. They also love to chase their own tail and jump on their shadows at night. 

Watching them do these things can be really entertaining!

Everyone’s laughing. And your dog’s enjoying all the attention.

Your dog’s getting a positive reaction from you and the other members of the family. So in their mind, they think of these crazy behaviors as a fun activity to do. 

What to do about it

There are many reasons why your dog could be suddenly acting crazy. 

To stop this behavior, you must first find out what’s causing them to do it. 

Do they get weird whenever they’re stressed or excited? 

Look out for signs and symptoms, if there are any. 

And if you can, reduce their exposure to what’s triggering them.

When to go to the vet

Self-diagnosing isn’t as accurate as having a professional’s advice. 

If your dog is showing symptoms of a disorder or a medical condition mentioned below, go to the vet.

  • Shaking.
  • Vomiting.
  • Panting heavily.
  • Becoming lethargic.
  • Difficulty in breathing.

25 scenarios of dogs acting crazy

#1: Dog acting crazy at night

Your Dog Is Acting Crazy At Night

After an exhausting day, it’s finally time to sleep. 


But wait, your pooch’s not ready for downtime yet. 

They’re still chasing invisible flies, running amok, digging for gold, and singing the song of their ancestors. 

“For Pete’s sake… 

Go to sleep, doggo.”

Certain factors could make your dog hyper and act crazy at night. Did they just eat before bed?

It’s also possible that there’s too much sugar in their food. 

Or they just exercised and they want to burn off some more energy. 

To make your dog calm down during nighttime, schedule their feeding time hours before they sleep. 

Also, check your dog’s food label. Empty calorie-sugars can make your dog hyperactive at night. 

Don’t hesitate to also check out: 9 Reasons Why Your Dog Is So Restless At Night + 9 Tips

#2: Dog acting crazy after neutering

Contrary to popular belief…

Some male dogs will not get rid of their aggressiveness as soon as they’re neutered.

In fact, one of this treatment’s side effects is reawakening a dog’s aggression. 

Your dog may also experience side effects and other behavioral changes such as:  

  • Hyperarousal.
  • Fearful behavior.
  • Snapping at you when you come close.

These effects will only last a short period. After that, your pooch will go back to their lovely and jolly self. 

To help them heal faster, you must keep their safety cones on. 

And always observe them if they show physical symptoms. 

Check if their incision is inflamed, bleeding, or having any discharges.

#3: Dog acting crazy running around

You get dizzy watching your dog run. 

They’re going back and forth and in circles. With a combination of jumping up and down

Thankfully, this only lasts for some minutes. Then they’ll be back to being calm.

Your dog does this because they’re getting the zoomies or a.k.a the Frenetic Random Activity Periods. 

It’s sudden bursts of energy that can drive your pooch a wee bit crazy at times. 

So what causes this?

  • Over-excitement.
  • Being in a stressful moment.
  • Having been confined in a crate for too long.

To limit your dog’s zoomie episodes, you mustn’t confine them in their crates for too long. 

For puppies, 3 to 4 hours is the longest time they can be inside it. This is because they can’t hold their poop and pee for longer than that. 

To keep your dog calm, make sure they get enough exercise outdoors. 

Therefore they wouldn’t be too excited every time they get the chance to go outside. 

#4: Dog acting crazy after flea treatment

You wonder why your dog’s acting very strange every time they come home from flea treatment. 

“Is this because of stress?”

Not quite. Is your pooch showing other symptoms such as:

  • Muscle tremors. 
  • Drooling and salivation.
  • Excessive scratching and licking.
  • Rolling on the floor and running around.

If they are, your dog may be having skin allergic reactions to the anti-flea treatment. 

Or they don’t want the smell of the product that was used on them.

Now, if your dog is showing serious symptoms, this could be a case of flea product toxicity or poisoning. 

When this happens, you need to take your dog to the nearest vet or poison control center immediately.

#5: Dog acting crazy after grooming

Your Dog Is Acting Crazy After Grooming

Unlike humans, dogs don’t like it much when they’re being groomed. 

Their fur’s removed or cut. Making them uneasy and cold during nighttime. 

Strangers touch and manhandle them. (There are even some groomers who also hurt dogs when they disobey.)

A reason why grooming can be traumatic for them.

No wonder your dog’s acting crazy. The experiences mentioned above can stress anyone out.

But grooming is an important thing for dogs. 

So to help them, don’t leave them alone when they’re being groomed. 

As long as they can see you during the process, they’ll feel secure.

#6: Dog acting crazy and itching

Your dog’s been acting funny. 

They’re scratching their butt and back on the walls, on the grass, and even at you.

“What gives, doggo?”

Some dog products that you might be using may be irritating your dog. 

This makes them itch, and it leaves a burning sensation on their skin. 

In more serious cases, they could also have allergic reactions. Look out for the following symptoms:

  • Itchy eyes. 
  • Constant sneezing. 
  • Difficulty in breathing.
  • Swelling of the parts of the face.

To avoid skin allergies, make sure to use hypoallergenic products when grooming your pooch.

Note: If your dog’s showing the severe allergic reactions mentioned above, take them to the vet at once.

#7: Dog acting crazy before labor

Based on how your pooch’s nesting, you know that they’ll go into labor anytime soon. 

They’re restless. 

Plus they scramble on their bed, finding ways to make it more comfortable. 

They may also try to move their nest to a different location. If this happens, you mustn’t touch it or try to move it. 

Anytime soon, they’ll also begin to shiver uncontrollably.

While these behaviors are normal, you must still check on them and be on stand-by for signs of labor.

To lessen your dog’s stress during this time, stay as calm as possible. 

#8: Dog acting crazy after vaccines

Side effects are pretty normal after vaccinations. 

According to PetMD, your dog may become lethargic. They could have soreness in their body part where the vaccine was administered.

They may also sneeze and sniffle if they were given nasal sprays. 

Observe your dog now and then for more serious reactions such as:

  • Difficulty in breathing.
  • Vomiting and diarrhea.
  • Loss of balance because of nausea.

If your dog’s reacting to vaccines in every appointment, ask their vet if it’s possible to skip some vaccines. 

#9: Dog acting crazy after eating chocolate

Eating chocolate is bad for dogs. 

The darker the chocolate is, the worse are its effects on your pooch. 

Your dog could experience

  • Vomiting. 
  • Shaking and seizures. 
  • Panting or difficulty in breathing. 
  • A sudden surge in energy that’ll make them pace around. 

So what do you have to do in case your dog consumes chocolate (or any food they’re toxic to)?

Take them to the vet immediately once they show the first signs of food poisoning. 

#10: Dog acting crazy lately

Your Dog Is Acting Crazy Lately

There are several reasons why your dog could be behaving crazy lately. 

It could be stress or they’re feeling some kind of body pain. In this case, you must observe your dog first. 

Know what’s bothering them and what’s triggering them to act crazy. 

Only then will you be able to give them the proper treatment they need. 

#11: Dog acting crazy during heat

During the mating season, dogs are uncontrollable.

They’re sex-crazy. 

They won’t listen to you, escape from your house, and come back when they’re mated. 

Twice a year, female dogs go to the heat cycle (estrous). The scent from their urine attracts male dogs as an invitation to mate. 

During this time, male dogs may get aggressive. They could also get obsessed with looking for the female dog who’s in heat.

To control this behavior, have your dog spayed or neutered. 

Reading tip: Can dogs get sexually attracted to humans? 

#12: Dog acting crazy and throwing up

It’s common for dogs to vomit. They do it whenever they ate too much food or after they munch on some grass.

What’s not common is when your dog’s acting crazy and throwing up at the same time. 

If this happens, they may have ingested something they shouldn’t have. 

Or they may be experiencing an allergic reaction causing them to pace around and paw at their face.

It might also be a symptom of a medical condition. Like gastrointestinal problems or acid reflux. 

Dogs who are not treated straight away may experience the following:

  • Fever.
  • Weight loss.
  • Dehydration.
  • Abdominal pain.
  • Decrease in energy.

If your dog is experiencing any of the symptoms mentioned above, you can try fasting on your dog for 24 hours. 

Don’t offer them any food. They can only drink water.

#13: Dog acting crazy after bath

There’s a long list of all the things your dog hates. And chances are, taking a bath is on top of that.

They look at grooming as a high-level stressful activity. 

After bathing them, your pooch will run around fast, go in circles, and shake their fur. 

They’ll even roll in the grass or the mud just to get rid of the shampoo smell in their body.

Thus making them dirty again. 

“Oh no!”

To control your dog’s zoomies, keep them inside the bathroom and blow-dry their fur. Let them calm down first before you release them.

#14: Dog acting crazy all of a sudden

Getting crazy is a dog’s specialty. 

I mean, they’re typically born with that personality. 

But this behavior can be alerting sometimes. Especially when their crazy actions lead to becoming a dangerous pooch. 

If not corrected, they may develop destructive behaviors such as:

  • Biting.
  • Attacking.
  • Jumping on people.
  • Growling and snarling.

If your dog’s acting crazy, you must first find out what’s causing them to behave this way. 

Is someone being aggressive towards your dog, and they act this way to defend themselves?

Or is it because a person or another dog is in their territory?

When this happens, the first thing you need to do is to calm yourself. This is the key to making your dog calm down too. 

If you can, remove the trigger, or move your dog away from it. 

And to make your pooch calm down, sit beside them and massage their ears in a circling motion. 

#15: Dog going crazy after a walk

You’ve heard that exercising your dog will lessen their chances of acting crazy. 

That’s why you took your dog on a long walk. And when you get tired, you let them run beside you while you roller skate.

“Why the heck are you still acting up?”, you ask your dog. 

You sigh in resignation as you look at them running around and tackling every piece of furniture in your house. 

There are possible reasons why your pooch may still behave this way. 

First, they’re annoyed that their playtime with you is over. 

And second, there’s still some energy left in their body that they need to expel before they sleep. 

An effective way to stop your dog from behaving this way is by distracting them. 

You can give them a toy they can play with once they get home. 

Or you can schedule their feeding time after exercise. This will redirect their attention to eating instead. 

#16: Dog going crazy panting

After some exercise, it’s normal for dogs to pant. 

“But Petya, my dog hasn’t exercised for today yet.

Why are they panting like crazy?”


If your dog’s panting heavily, then this may be a serious medical concern. According to WebMD, your dog could be experiencing: 

  • Poisoning.
  • Heatstroke.
  • Respiratory problems. 
  • Chronic illnesses such as heart failure.

When this happens, you need to observe your dog closely. 

Check if their tongue’s color has changed to blue or pale white. This is an indicator that they’re losing oxygen. 

Take them to the vet immediately once their pants become alarming. 

Read also: Why Does My Dog Suddenly Pant? 19 Dangers + 5 Tips

#17: Dog going crazy on the snow

Who doesn’t enjoy the snow?

Kids, as well as adults, love it. So it’s not surprising at all that dogs will go crazy for it. 

It’s soft, fluffy, and cold, making it ideal for a playing area. 

Dog breeds like the Siberian Huskies and Alaskan Malamutes are total suckers for snow. That’s why they’re known for being sled dogs. 

But be careful. 

If your dog isn’t used to playing in the snow, they may have frostbite and hypothermia.

#18: Dog going crazy barking at nothing

Sometimes you wonder if there are ghosts in your house.

Because, well, your dog barks at nothing, especially at nighttime. 

But there’s no one else in the house. Just the two of you. 

The reason behind this isn’t because there are spirits in your home. Maybe, the little culprit here is much smaller than what you have in mind. 

Dogs are natural predators. And at nighttime, they may enjoy playing the hunting game. 

It’s possible that there are insects and vermin in your house.

There could be termites hiding behind your walls that only your dog can hear. Or mice that run around when you get to sleep. 

#19: Dog going crazy licking everything

Dogs may crazy lick on things when they’re feeling nauseous. 

Or it could also be because of the following things:

  • Separation anxiety. 
  • Nutritional deficiency.
  • To relieve mouth pain.
  • Gastrointestinal problems.

To know why your dog does this behavior, you can ask for a vet’s advice here

Read next: 13 Reasons Why Your Dog Licks Your Pillow + 7 Tips

#20: Dog going crazy in crate (kennel)

Housetraining is important for every puppy in a household. 

During this time, dog parents keep their dogs inside their crates. This is to train them not to go potty or urinate inside the house. 

“But what will I do? 

My pup goes crazy when I put them inside the crate? 

They whine and bark non-stop.”

It seems like your dog is scared of being confined. In this case, you have to condition them that being inside it isn’t so bad. 

Make their crates comfortable by leaving their favorite blanket there. You can also leave them with toys and treats they can munch on. 

#21: Dog going crazy on leash

Dogs get uncontrollable on a leash when they’re not exposed to outdoor activities much. 

That’s why they tend to become overwhelmed with everything they see and smell. 

The problem here is when they get so crazy that they’ll attack other dogs they meet on the way. 

They could also jump on joggers and other people on bikes.

So to avoid this problem, you must exercise your dog daily. Take them outdoors as often as you can.

By exposing them to other dogs and people, you’ll develop their social skills too. 

#22: Dog going crazy at 6 months

If you think puppies are crazy, you haven’t seen a dog in their ‘puberty’ stage yet. 

They’ll test your boundaries. 

“How much can I eat?

How much can I destroy before my human gets angry?”

In this life stage of your dog, you must correct and train them properly. Or else they’ll misbehave further once they get to adulthood. 

#23: Dog going crazy with cone

Imagine having a cone around you restricting your movements. 

Not very comfortable, is it?

Your dog thinks the same way. After treatment, your dog wants to be as comfortable as they can be. 

But the cone that’s blocking their way is making them stressed and uneasy. So they do all sorts of things to try to remove it. 

They’ll roll around the floor, paw on it. And even attempt to bite on it. 

Well, the only thing you can do about this is to distract your dog. 

Play with them or give them challenging toys to keep them busy.