Why Is My Pet Rat Suddenly Aggressive?

Pet Care


September 28, 2020

Domesticated rats are underrated, fascinating animals that make fabulous pets. They have many things in common with other companion animals. They groom themselves several times a day as cats do, and they’re affectionate like dogs are. They even have a lot in common with us humans: one-fourth of the human genome is shared with rats!

Extraordinarily social and endearing animals, pet rats bond with their owners, learn their names and even respond to them. They seek attention, like to play, and enjoy affection. They’re also surprisingly intelligent animals: these clever rodents can learn many neat tricks, like clapping or shaking hands. They also have the impressive capacity to recreate social hierarchies between each other.

Aggression in Rats: How to Identify It and How to Deal With It

If you’re considering adopting a pet rat, you may be wondering if rats are aggressive. The short answer is no. Domesticated rats are bred to be gentle. Generally speaking, a pet rat should not pose harm to you if you are gentle and caring. 

However, certain underlying issues can cause a rat to be aggressive.

You may already have an aggressive pet rat, and you may be trying to figure out why it’s behaving this way and how to tame it. We’ll cover all you need to know about rat aggression so that your furry companion is as docile as can be!

Follow our tips, and your pet will be asking for belly rubs and licking you to show affection in no time.

Signs of Aggression in Rats

Even though every rat is unique, with their own personality and needs, they generally tend to be personable animals that crave attention, interaction, and affection. Friendly behavior is normal rat behavior. You should be expecting your pet to roll over, asking for belly rubs, to lick you, to enjoy having its shoulders scratched, and to like playing!

It’s important to analyze your pet’s behavior to know if they’re happy, healthy, or have an underlying problem causing aggression. There are many signs to look out for.

  • Fleeing or hiding

This behavior on its own does not indicate that a rat is aggressive. However, if the following signs accompany it, you’re likely dealing with an aggressive animal.

  • Hissing or exposing teeth

Making a hissing sound is an audible indicator you may witness when you try to touch an aggressive rat. It’s a way for them to show that they feel threatened by trying to seem menacing to you.

A rat also shows dominance by exposing their teeth while tilting the head. This usually happens when trying to touch or pick up an aggressive rat, similar to how a dog would growl.

  • Posturing

Another physical demonstration of aggression your pet rat may exhibit is becoming rigid to fluff up its fur and appear larger. In this case, your pet rat rocks from side to side, standing on their toes sideways to the person or animal that they feel threatened by.

  • Lunging

It can occur among rats as a threat or intent to attack, followed by biting. Aggressive rats may lunge at your hands or face whenever you get close to the cage.

  • Starting fights frequently with other rats

Some fighting is natural and normal among rats. Still, if it occurs too often (several times a day) and the fighting causes injuries, it’s a red flag. Especially if the violent conflict is occurring all of a sudden between long-time cage mates. 

  • Aggressive biting 

Not all biting should be considered hostile or malicious. It’s crucial to take into account that rats have poor eyesight and might misinterpret certain situations. Distinguishing playful biting with harmful, more aggressive biting is essential. Rats will often bite as a sign of affection or playfulness.

You can determine if it’s malicious or not by analyzing the situation where it occurs and how hard or painful the bite is.

On the one hand, rats may nibble and bite you when they think you have a treat for them. Your furry companion may bite you unintentionally while playing with you, or wrestling with your fingers, for example.

Pet rats may even bite your finger to pull it into the cage as a way of indicating that they would like you to play with them!

If the rat bites your finger thinking it’s a treat, it will let go and may even apologize by licking your finger. On the other hand, if the bite isn’t painless, occurs more than once, or draws blood, it’s a clear sign of aggression.

Again, it is not common to see pet rats biting people aggressively. People that sleep with food residue on their hands or faces, like homeless people, are more likely to be bitten by rats. However, this has more to do with feeding than actual aggression.

Causes for Aggressive Behavior

Knowing how to recognize signs of aggression is crucial, but understanding the causes is just as essential to determining if you can solve the issue at hand. Aggression can often be alleviated or solved.

However, if aggressive behavior is a result of improper breeding, a significant improvement is unlikely. To avoid this, try to meet the parents of the rat you’d like to adopt.

  • Provocation

Taunting will make rats more prone to aggression, as they may try to fight their way out of confrontation, just like many other animals will. Purposely hurting a rat can make them suddenly aggressive. Abusive behavior (by you or someone around the pet) can cause aggression, and this should be a no-brainer.

Examples of behaviors that can hurt your furry friend are pulling or picking them up by their tail, harsh poking, flicking, pinching, throwing, spraying, grabbing too tight, etc. Providing inadequate living conditions can also be a precursor for distrust and aggression.

  • Illness or pain

If your furry companion has never shown signs of aggression before and is all of a sudden displaying hostile behavior, it may be a sign that they’re sick or in pain, and it may be wise to visit a vet.

  • Maternal aggression

It is not uncommon for some rats to be very protective of their babies. You should always handle a new rat mom very cautiously so that you or the babies aren’t harmed. To do this, try to coax her with food or with a treat. This aggressive protection becomes less pronounced as the babies get older.

  • Stress

Rats show stress in various ways. These include bruxing or teeth grinding, and secreting porphyrin through the eyes, ears, and nose. Another indicator of stress, anxiety, and fear is the exhibition of aggressive behaviors. It’s important to examine what could be causing your furry friend to be stressed.

  • Trauma or abuse

Rats that have suffered abuse or poor treatment may display aggressive behavior due to fear caused by humans. Depending on the trauma’s severity, you may experience extremely aggressive behavior.

Tips and Pointers to Keep a Pet Rat Docile

You should always try to deal with the root causes behind the violent behavior and do your part to make sure your pet rat feels safe and calm.

However, it’s worth noting that some rats will not budge. It’s best not to carry on trying to tame a rat that relentlessly and viciously attacks the people around them. A severe rat bite can cause serious medical injuries.

Testing your rat’s temperament towards people may be a good starting point on your journey to help your rat become calmer. Putting them around people and seeing their reaction will show you if they’re aggressive.

If your rat is displaying violent behavior towards other pet rats, it’s crucial to act quickly. In this case, don’t hesitate to separate your pets into different enclosures! Otherwise, one of the rats or both could be facing an existential risk. They should remain separated until, through a step by step process, you reintroduce them.

If your furry friend is displaying violent behavior towards people through biting, for example, it may be a matter of the severity. If the bites don’t cause bleeding, there’s hope you can tame your pet rat with some patience and time.

When it comes to feeding time, make sure you don’t feed them through the cage’s bars. This will help your pet avoid mistaking your fingers for food.

It’s essential to keep in mind that hostile pet rat behaviors likely stem from fear. If that’s the case, focusing on gaining or regaining the rat’s trust is crucial. If you want to approach your pet, do so slowly. Be gentle and patient, do what you can to ensure that you won’t be triggering fear.

A method you can try if you want your pet to trust you is to approach them slowly, waiting until you can notice calm behavior. Once you do, reward your pet by moving away. This will ensure the rat that having you around isn’t so bad.

If repeated, this exercise can help your rat manage their emotional state and see you in a more positive light by realizing that you’re not a threat.


Rats are often misunderstood. Their endearing yet quirky nature captivates anyone who dares to spend enough time getting to know them. Although having a rat as a pet can be a blast, it can also be challenging. While they’re gentle most of the time, they’re sensitive animals that can get aggressive.

With the right knowledge, though, you should be able to pinpoint why they are aggressive and how to solve it!