Why do Cats Puff Up and Run Sideways: Mysteries Revealed

Silly, cuddly, and pointy on five ends, cats are mysterious creatures that have lived with humans for centuries. As pets, they can help extend your lifespan. As successful hunters, they keep down the pest population, yet so much of their behavior can confuse us. Whether they get the zoomies and decide they have an appointment in the other room, or make that strange clicking noise at birds outside, cats like to leave us confused. The great news is that it’s not random behavior. As a cat owner, I’ve learned a lot about their behavior from my vets and other resources in the last thirty years. Now, I’m going to share one of the great kitty-secrets with you.

Why do cats puff up and run sideways? Cats puff up and run sideways as a defense. Looking larger gives them an advantage, and moving sideways allows them to remain as big as possible while attacking or escaping. A cat who feels insecure or angry will do this as a way to scare off other animals or people. 

Why Cats Puff Up: Bigger, Better, More

Birds sometimes fluff up when they’re happy. Could your cat be doing the same thing? Actually no. Cats do not puff up to express joy. They use their fur as a signal of their bad mood, or to ward off perceived threats. Even if there’s no real danger, a cat will puff up if they feel threatened.

Like people, cats can have bad dreams or vivid imaginations. However, most of the time, if your furry friend is feeling threatened, there’s some practical reason. They might respond this way to a young child who pulled their fur or ears, or a dog. Cats can also feel threatened by other animals or objects they find strange. Even a mirror can freak them out.

Especially if your cat is new to your home, they might react like you’re the threat. However, it can also be a cry for help if they’re hurt and feeling vulnerable. If lots of kindness and slow gentile interactions aren’t working, you may have a kitty that needs to go to the vet.

Non-Verbal Communication: Puffed Up Cats Are Talking

Even the most vocal and intelligent cats can’t speak with us like an adult human. They communicate their feelings and intentions in other ways, like when your cat puffs up. Listen to what they’re saying.

Body language is a big deal for your cat. When they try to make themselves bigger, they’re telling you to back off. If you approach a puffed-up cat, you’re probably about to be on the wrong side of a slashing. Reaching out might get you bitten or clawed.

Cats are a lot like people in some ways. Rather than backing your fur-buddy into a corner and making things worse, remove the threat. First, step back slowly. Next, if the problem is an object or mirror, remove it. Alternately, when the danger is another animal, it depends on the situation.

Sometimes you only need to close some curtains to get rid of the threat. Other times you’re introducing a new pet to your home, and it’s not that simple. Regardless, keep your own body out of danger.

Raise A Happy Pet

One of the best ways to cope with this odd behavior, other than giving the cat space, is to raise them happy and healthy from the get-go. Like human babies, it’s not always easy to raise a great pet.  I suggest you pick up a RundA Cat Scratching Post from Amazon which gives your puffed up and grumpy, or playful cat a place to scratch, plus interactive toys that interest them. This helps your fur-baby handle their need to hunt and play. You can get one by clicking here

Your Cats’ Basic Needs

If your cat is acting out by puffing up and running sideways, make sure their needs are met first. Pets, like humans, have basic needs. As a pet parent, it’s your job to provide these things just as you would for a human child. The list isn’t in order of importance, because they need all of these things.

  1. Love- Kitties need affection and attention from you. They may get angry or playful and puff up at you.
  2. Food & Water- Indoor kitties need healthy meals and clean water daily.
  3. A Bed- Cats need a comfy place to sleep.
  4. Toys- Cats need to play. It reduces stress and helps them handle instincts like hunting. If your cat is running at you sideways, they may be trying to tell you they need something to play with.
  5. Something to Claw- Cats scratch because it’s how they sharpen their claws.
  6. Someplace to Climb- Climbing in trees is how cats in nature sleep safely and watch for prey.
  7. Shelter- As domestic animals, cats need the same heat, cooling and roof over their heads that people need.

Arched Back: Part of the Puff Up Process

Typically, when your cat does the puffing up and running sideways, they will arch their back as well. Sometimes a cat who is arched and puffy is having a stretch after their nap. Cats have sixty vertebrae in their back, which is almost twice as many as we humans have with our thirty-three. Moreover, cats have about forty more bones than we do overall.

When a cat wakes up, standing up, and arching their back is just a stretch to make them feel good. Sometimes this comes with fluffed out fur. Sleeping on all that fur can cause it to lay wrong. A quick puff up will cause the hair to go back to a more normal position.

Alternately, when they feel threatened, cats also arch their spines. Along with the fur puffing, it gives them more apparent size. By adding height, they can sometimes intimidate whatever or whoever is threatening them.

Posturing in the Wild

We may think of our fuzzy housepets as entirely domestic, but they’re not. They still have all the instincts of a wild creature, and puffing up is part of that. In nature, animals don’t always fight by hurting each other.

There are no vets in nature. As a result, animals often resort to territorial displays or intimidation tactics. By fighting it out with looks and sounds, animals avoid unnecessary injuries. An infected cut can kill if you have no way to treat it.

Hence, the instinct to respond to fear and threats by getting bigger is just part of who they are. After all, it’s better to be safe than sorry. This is known as agonistic behavior.

Making a display like this is the animal world version of playing chicken. Whoever backs down first is the looser. It keeps both parties from being hurt and establishes dominance. When females are around, it can help them decide who the most worthy male is to mate with as well, though domestic cats aren’t quite as picky as some species.

Why Cats Move Sideways

Strange strafing, or skittery hopping, sometimes this sideways running is called sidewinding. While it may look odd to you, it does serve a purpose. Sidewinding allows the cat to maintain its back-arched, fluffed-up position.

The ability to run at an opponent sideways while staying as large as possible may not seem intimidating to you. However, for most creatures, it’s a startling move. When a cat virtually doubles its size and makes an aggressive move like this, it’s shocking. Just as a human army uses shock and awe, so do cats.

It doesn’t frighten humans because we’re apex predators. If it were a lion instead of a housecat, you’d be afraid. At least, you would if you had any sense.

Apex predators are the top of the heap. Other than humans, most of these predators have no other serious natural enemies. Nothing hunts the apex predator. Large cats are definitely among these predators. However, small housecats are related to these big guys. They have the same instincts and roots genetically.

Cats Vs. Kittens: Breaking Down The Puff Up & Run Sideways Behavior

The same behavior can have very different meanings depending on the age of the animal who’s displaying it. Not all puffing up or running sideways is the same. Just as baby animals play at wrestling, they play at other forms of aggression. This is how they learn to behave like adults.

It’s normal and healthy for cats of any age to puff up and run sideways. However, not all cats will do this. Some are just so comfortable and relaxed that they never have any serious concerns.

Likewise, some babies don’t learn all the adult ‘tricks.’ It’s okay if your cat or cats never behave like this. Similar to people and other mammals, they may not require that skill, though most cats will at least give it a try at some point.

When To Worry

Every pet-parent has to make their own decision about what they find alarming. If you’re looking for a great resource to help you figure out if your cat is misbehaving, I suggest your read Behavior Problems of the Dog and Cat 3rd Edition. I picked up my copy from Amazon, and you can too by clicking here. It’s been incredibly helpful in decoding and dealing with my cat’s behavior. 

Adult Cats Running Sideways

When adult cats get scared or angry, their behavior is aggressive. Puffing up and running at you sideways is an attempt to get you to back down. While it may seem silly and cute to you, the cat is deadly serious.

They may try to harm you if you don’t leave them alone. Usually, for an adult cat who is alarmed, they will accompany this behavior with hissing, growling, or spitting at you.

These verbal cues are a way to show you how serious they are about this fight. They’re showing you, in a different way that they’re mad and they want to fight. If you provoke them, they will probably try and hurt you.

Kittens Puffing Up

When young cats, sometimes as early as just seven or eight weeks old, display the sideways puff up and run, it’s not quite the same. Though they are perfectly capable of doing this out of anger or fear, that’s almost certainly not what’s happening. Unless the kitten is in front of a mirror, strange animal or other threat, they’re playing.

You can usually tell the difference because kittens tend to hop instead of running. It’s very easy to tell a kitten from an adult cat because of size and body proportions. Plus, they almost certainly aren’t going to hiss and spit while playing.

This behavior is an invitation to join them. You can get down on your hands and knees to mommick them. That’s good cat-manners. However, it’s not a great idea to encourage them to bite or scratch at you. Training a young cat to attack humans, even playfully, is going to tell the adult they will become that it’s okay to bite and scratch you.

Adult Cats Play Puff Up Too

Though it’s much less common, some adult cats will play by getting puffy and taking sideways hops or dashes at you. Some cats are naturally more playful and aggressive than others. They may just be goofing around.

If the cat is hopping and not hissing or giving other signs, and when the cat knows and trusts you, they may just be playing. Most adult cats lose this behavior as they age, but not all.

Final Thoughts

Cat care can be tricky at times. When your pet puffs up and starts running sideways, you may not know what to think. Hopefully, I’ve helped to decode the bizarre behavior for you.

It may surprise you to know that cats don’t act without reason. Everything they do has meaning and purpose, even when you ‘don’t get it.’ It matters to your pet.

If the cat is scared, try to remove the problem, even if it’s you. Conversely, if they’re trying to bait you into playing, take a few minutes to goof around with your favorite fuzzy friend.

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