10 Reasons For Aggressiveness in Chihuahuas

Everyone remembers the time when the Chihuahua had celebrity status. They made an appearance in cult classics such as Legally Blonde. Madonna and Paris Hilton had pet Chihuahuas, increasing the breed’s popularity across the United States. However, much has changed since then. The breed’s popularity has faded somewhat, and many people claim that Chihuahuas are very aggressive dogs.

Regardless of the truth of that assertion, many factors play a role in creating an aggressive dog. Chihuahuas are aggressive due to poor ownership, lack of training, health issues, and anxiety. We will discuss these reasons in extensive detail and provide tips on how to handle an aggressive Chihuahua.

Brief Chihuahua History

There is no definite answer to the origin of the Chihuahua. Though discovered in Mexico, their origins are still a mystery. Historians believe that the modern-day Chihuahua descended from the Techichi breed. There are various ancient paintings in Mexico that feature dogs resembling Chihuahuas.

Techichi dogs were a popular pet in Aztec civilization. While the Techichi breed was originally much larger than the modern Chihuahua, the Aztecs selectively bred it into a compact, lightweight lapdog. When Spanish conquistadors imposed their rule on the region that is now Mexico, the Techichi breed vanished and was thought extinct.

It wasn’t until the 1800s that people discovered Chihuahuas in the state of Chihuahua. The American Kennel Club (AKC) first registered the breed in 1908. In modern times films like Legally Blonde, television shows like Sex and The City, and even commercials for fast-food giant Taco Bell featured Chihuahuas, causing their popularity to skyrocket. Their popularity grew immensely during the 2000s and then declined slowly. Currently, Chihuahuas are the thirty-fourth most popular dog breed in the United States of America.

Chihuahua Temperament

The term “aggressive” generally describes a Chihuahua’s behavior and temperament. Some people also use the word “mean” to describe Chihuahuas and their personalities. These are generalizations and certainly don’t apply to every Chihuahua. Many pet parents with a Chihuahua would tell you otherwise.

There is no denying that Chihuahuas have an attitude that might not sit well with everyone. They can be bossy and assertive, unusual traits for a dog of their stature. Some Chihuahuas can also be stubborn and difficult to train. However, with firm, gentle training and early socialization, Chihuahuas make loyal and affectionate companions. They are immensely devoted to their owners and will go out of their way to protect them.

Chihuahuas can be aggressive because they are very protective of their space and owners, making them great watchdogs; many people adopt them for this very reason. Most people who adopt Chihuahuas don’t realize that their protective nature is instinctive. Early training and socialization keep the Chihuahuas’ attitude in check. Exercising patience is key since it can take months fr Chihuahuas to warm up to other people.

Additionally, Chihuahuas are highly excitable dogs. They have a lot of energy that needs a release. If neglected and not given enough exercise, they can develop behavior problems. Unfortunately, aggression and destructive chewing are common behavioral issues that neglected Chihuahuas develop.

What Is Aggressive Behavior?

Now that we know about the Chihuahua’s history and temperament, we can dive into why this breed can be aggressive. However, it is important to understand the ways aggression can show. Aggression does not simply mean barking, growling, and biting. Dogs give multiple warning signs when uncomfortable before resorting to aggression. Once you learn to recognize the warning signs, you can manage an aggressive Chihuahua better.

Dogs use body language to communicate their emotional state. Learning to read your dog’s body language is crucial to preventing unwanted behavior. Some of these signs aren’t an indication of aggression alone, but only when combined with other signs. You can judge how angry your dog is feeling by the number of signs he shows. Before a Chihuahua attacks or starts growling, it will generally show the following signs:

Tail Stops Wagging

We often only look at a dog’s tail when we assume they feel happy. The tail can tell us multiple things about how a Chihuahua is feeling. While a wagging tail can indicate happiness, it can also indicate agitation when stiff and wagging rapidly, almost like it’s vibrating. Similarly, a Chihuahua that is feeling threatened will stop wagging its tail. If the tail is still and positioned high, it is a sign that your Chihuahua feels threatened.

Raised Hackles

Hackles are the hairs that grow along the Chihuahua’s back till the tail. Raised hackles can indicate emotions such as excitement, fear, or anger. If you notice raised hackles, watch out for other signs of anger.

Stiff Posture

A stiff posture usually accompanies a raised tail and hackles. An angry Chihuahua may put all its weight on its front legs to look bigger. The posture seems rigid, and the Chihuahua may become completely still.

Eye Contact

Dogs use their eyes to communicate too. They use a “look away” technique to communicate that they are not comfortable with the current situation and want everyone to calm down. However, a dog that locks eyes with other dogs or humans says, “I am ready for a fight.” 

Baring Teeth

Before a Chihuahua growls, it will bare its teeth as a warning sign before they get ready to nip or bite. If a Chihuahua starts showing his teeth, it is best to back away slowly. Reassure your Chihuahua, but avoid touching him as this can agitate him further.


Growling and snarling mean that your Chihuahua is feeling angry. Before they snarl, they will start to growl quietly. When you hear a Chihuahua growling quietly, this is a warning sign. You could be crossing a Chihuahua’s boundaries to elicit this behavior so stop immediately.

Reasons For A Chihuahua’s Aggressiveness

Many reasons can trigger aggressive behavior in a Chihuahua. Like other breeds, they have quirks you should know. Many people don’t take a Chihuahua’s anger seriously because they are so small. Ignoring your dog’s warning signs can lead to aggressive behaviors in the long term. The common reasons for Chihuahuas can be aggressive are:

1. Territorial Aggression

Despite their diminutive size, Chihuahuas make great watchdogs because they are protective of their space and humans. They are willing to attack strangers at home or in the dog park. Anyone meeting a Chihuahua for the first time should not expect them to be friendly. It takes them a while to warm up to unfamiliar people.

Understand that these are a Chihuahua’s boundaries. The place where they rest is only accessible to the ones they trust. You should not welcome strangers into a space that your pet has marked as theirs. It takes time and patience to familiarize Chihuahuas with unfamiliar people, even if they are friends and family. When they meet someone multiple times, they warm up to them eventually.

2. Fear

Chihuahuas are tiny dogs, so other people and dogs appear large to them. They tend to be fearful around unfamiliar faces, and aggression is simply a defense mechanism. They are only comfortable around their owners and will react negatively to strangers. Chihuahua puppies need socialization and training to become comfortable around unfamiliar faces. If you don’t train or socialize your pet properly, they will rely on aggression to cope with their fear.

Fear doesn’t need to always lead to aggression. Some Chihuahuas may become withdrawn because they are constantly fearful. Both habits will require a professional behaviorist’s intervention.

3. Poor Training

It can be difficult to say no to your Chihuahua when he is a puppy. They are small and adorable, making it difficult to deny them what they want. However, not teaching your pet boundaries can be detrimental in the long run. Dogs are territorial and believe deeply in the pecking order. Chihuahuas have strong personalities, so they will naturally try to dominate.

In some cases, pet parents might act leniently toward a Chihuahua despite aggressive behaviors. When they let aggressive behaviors slide, pets can develop a pattern of engaging in bad habits. If a Chihuahua learns that there are no consequences to such actions, they will practice them repeatedly. Chihuahuas’ aggressive behavior should be tackled the same way as a larger breed.

You have to deal with this behavior firmly and strictly. Do not give in to a Chihuahua’s aggressive behaviors or whining. Setting clear boundaries requires practice. Setting boundaries does not mean that you should punish your dog; it means consistent training using positive reinforcement. Exercise patience and gently reassure your dog when they start acting this way. Early socialization and obedience training is essential for preventing aggression in adult Chihuahuas.

4. Pain

Chihuahuas are prone to many health issues. These include painful conditions such as hip dysplasia, patellar luxation, cardiac problems, and Legg-Perthes disease. A Chihuahua that appears aggressive could be in a lot of pain. These dogs are very small, so their bones and joints can be quite fragile. A Chihuahua who suddenly becomes aggressive could be suffering from health issues.

If your Chihuahua constantly gets sick, it could be acting aggressive because of painful conditions. Consult your veterinarian about how to cope with this behavior. Your dog will need pain medications to prevent discomfort.

5. Anxiety

Many factors can cause anxiety that leads to aggressive behavior. Separation, past trauma, and major life changes can cause anxiety for your Chihuahua. Like fear, aggression can serve as a way to cope with anxiety. If you are rescuing your Chihuahua from a shelter, learn as much as you can about his previous owners. If the previous family was abusive to your pet, it could lead to aggressive behaviors.

Chihuahuas also enjoy routine and can develop behavioral problems if exposed to unfamiliar situations. Moving houses, the death of a family member, and the death of other pets can cause stress and anxiety for a long time. Consult your veterinarian about the best way to tackle your Chihuahua’s anxiety.

6. Small Dog Syndrome

Small Dog Syndrome is a non-scientific term describing the trait of some small dogs acting overly aggressive to make up for their lack of size. Small Dog Syndrome is not a genetic condition. It develops by not addressing a small dog’s aggressive behaviors through training and socialization.

Undesirable behaviors in small dogs are either ignored or rewarded. Chihuahuas who have Small Dog Syndrome don’t just act aggressive but can also show other behaviors. These include not listening to commands, jumping atop furniture without permission, pulling on or refusing to walk on a leash, and begging for food.

7. Lack of Exercise

Many people think that Chihuahuas don’t need exercise because they are so small, but lack of exercise can cause multiple health and behavioral issues. Chihuahuas are very energetic, and exercise helps them release their energy. If they don’t get enough exercise or mental stimulation, they can grow bored and develop destructive habits. Unfortunately, behavioral problems aren’t all that arise from lack of exercise. Obesity is a common health problem among pets who do not exercise, and it’s especially harmful to small breeds, where excess weight can strain bones and joints.

8. Breeding Issues

Poor breeding can also create dogs with behavioral problems. Many people don’t know that the American Kennel Club (AKC) does not recognize “teacup” Chihuahuas as a breed. However, due to the high demand for these small dogs, many breeders use unethical practices to create them. To create teacup dogs, breeders often pair the smallest or the “runts of the litter.” There are significant health risks for these puppies, and many of them grow up with a host of physical and behavioral issues. As a result, these dogs spend a large portion of their life in pain and can become aggressive.

9. Neglect of Warning Signs

Some people assume that because Chihuahuas are small and harmless, there are no consequences to crossing their boundaries. Imagine a larger dog baring its teeth and growling. Anyone would stop bothering such a dog immediately. However, many people ignore a Chihuahua’s warning signs or encourage them because they think it’s cute.

A small dog’s boundaries should be respected as if it were a big dog. If your Chihuahua shows any of the warning signs mentioned above, back away slowly and do not try to pick up your dog or dismiss the signs.

10. Heat

It is common for behavioral changes to occur when your dog is in heat. Male and female Chihuahuas can both become aggressive when in heat. Spaying/neutering your pet can prevent aggression and improve their temperament. Chihuahuas also struggle to deliver puppies, so it is best to spay your pet. Spay/neuter surgery also has various benefits, such as preventing uterine and breast tumors.

How To Handle Chihuahua Aggressiveness

Dogs love routine, and your Chihuahua is no exemption. Being unaware of what is happening around you or losing control of a space you felt secure in can elicit feelings of self-doubt and frustration. Your pet is not exempt from feeling that way about their surroundings. Being able to care for your dog requires thoughtful investigation into what they want and how they interact with their environment.

It is your duty as a pet owner to be aware of what your dog needs and how to provide it to them. An aggressive Chihuahua may be lashing out at others due to difficulties they experience.

Train/Socialize Your Chihuahua

Like many other breeds that show territorial aggression, Chihuahuas need to be trained and socialized early. Have your puppy interact with other people and pets under your supervision. Take them to dog daycare centers where they can socialize with other animals. Early intervention is the best way to prevent aggressiveness in adult Chihuahuas. If you have an adult Chihuahua with aggression issues, training can take a while to show effect.


Observe your dog’s social cues and see what struggles they face during real-life interactions. Please provide them with attention at the appropriate time, so they know they can trust and rely on you. Your Chihuahua is small, fragile, and has its quirks. Observe your dog when interacting with others to learn about their issues. If your Chihuahua is being aggressive, there is probably a trigger you can uncover through observing them. It can be helpful to know why your dog does something to prevent it in the future.

No Assumptions

Many people assume that breeds like the Pitbull, Rottweiler, and Chihuahua are naturally aggressive. It is unfair to assume that your dog’s breed is the problem. Aggression occurs due to changes in your dog’s environment that they have difficulty handling. When adopting a Chihuahua, you should know their needs and temperament.

Avoid Punishment

Avoid punishing your Chihuahua for aggressive behavior at all costs. They are small and sensitive to training collars. In most cases, an aggressive dog only behaves so due to external reasons. If you try to punish your pet, they can become more aggressive or fearful/withdrawn. It can be difficult not to reprimand your Chihuahua for this behavior, but there are other ways to handle it. If your Chihuahua behaves very aggressively, isolating her can help her calm down. The key is to wait for your dog to calm down before you try to intervene.


Sometimes words aren’t enough. Getting through to your Chihuahua will require positive reinforcement strategies. Establishing a reward system for your Chihuahua’s good behavior will help encourage and maintain it. You can give your dog a treat when they follow your commands, cuddle, and pat them. Tell them they’re a good dog when they do something you like. At times, positive reinforcement may not be enough for a stubborn Chihuahua. In this case, consulting a professional is necessary. If aggression issues are difficult for you to handle, a professional’s help can make things less stressful.

Talk To Your Veterinarian

Painful health issues can cause your Chihuahua to become aggresive suddenly. Dogs cannot communicate the way humans can, so it is important to rule out any medical conditions.

The ASPCA defines this as “pain-elicited aggression,” which is common among dogs suffering from painful health conditions. Senior Chihuahuas who suffer from arthritis can also behave aggressively.


Ensure your Chihuahua is getting enough exercise. Exercising is a great way for you and your pet to bond and constructively release energy. All dogs have certain exercise needs, which can create issues when unmet. Chihuahuas who do not get enough exercise and mental stimulation can grow bored and frustrated, leading to aggressive and destructive behaviors down the line. Chihuahuas are quite small, so they don’t need much space to exercise. Ensure your pet gets at least an hour of exercise a day.


It is common for dogs to behave aggressively when in heat. Whether your Chihuahua is male or female, they can show aggression during their heat cycles. Female Chihuahuas can have an irritable mood, while male Chihuahuas will show aggression towards other male dogs. It is important you spay/neuter your pet to prevent sex-related aggression. In addition to preventing aggression, it can also reduce the risk of certain illnesses. Spayed/neutered animals live longer and are at low risk for health conditions that affect the reproductive system. Repeating heat cycles can also cause health issues such as Pyometra and false pregnancies.


Are you willing to take the time and pay the price to solve your Chihuahua’s aggression issues? Aggression resolves with proper training in most cases, but it takes time, effort, and patience. If you feel it’s not safe for your family members to be around your Chihuahua, discuss these issues with your veterinarian. You should make the best choice for yourself, your pet, and the ones you love.

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