Rat Terrier Chihuahua Mix (Rat-Cha) Dog Breed Facts

The Rat-Cha is one of the most popular designer breeds. Made up of two lovable breeds, it’s sure to warm your heart. Find out more here!

The Rat Terrier Chihuahua Mix, also known as the Rat-Cha, is a cross between a Chihuahua and a Rat Terrier. It’s a small breed known for its high energy and affectionate personality. Rat-Chas are known to be protective of their families and enjoy spending their time playing with their families.

As you read further, you’ll learn everything there is to know about the Rat Terrier Chihuahua Mix. First, you’ll find out about the history of the breed and how it was developed. Next, I’ll discuss the Rat-Cha’s personality and appearance. You’ll also learn about how to take care of a Rat-Cha and its different needs. Finally, I’ll discuss the common health problems that Rat-Chas face.

The History of the Rat Terrier Chihuahua Mix

Since the Rat Terrier Chihuahua Mix is a designer breed, not much is known about its development. The breed first appeared in the 1990s and has quickly rose to popularity ever since. Rat-Cha breeders claim that this breed is the best designer dog. To have a better understanding of the Rat Terrier Chihuahua’s history, I’ll quickly go over the histories of its parent breeds.

The Rat Terrier was developed by 19th century American farmers. They needed a small breed that could easily hunt rats that often disturbed and ruined their crops. To do this, they bred multiple types of Terriers with Whippets, Greyhounds, and Beagles to eventually create the Rat Terrier. Former president Theodore Roosevelt was even fond of this breed and had his own Rat Terriers. These Rat Terriers were known as “Teddy’s Terriers.”

Chihuahuas are the smallest dogs in the world. They originate from Chihuahua, a state in Mexico, which is also what the breed was named after. Chihuahuas date as far back as 100 AD, earning them a solid place in Mexican history. It’s believed that Chihuahuas are descended from an ancient breed called the Techichi, which was a dog that was used for sacrificial ceremonies in Aztec culture. Today, Chihuahuas are one of the most popular dogs in the world, especially among celebrities and influencers.

The Personality of the Rat Terrier Chihuahua Mix

The Rat Terrier Chihuahua Mix is an active dog that is highly affectionate. It typically bonds with one person in each family. You’re sure to find that your Rat-Cha will have a favorite in your household! These little dogs tend to be aggressive towards other dogs and small children so it’s important that you socialize your Rat-Cha as early as possible.

Rat-Chas are also known to have separation anxiety. It’s best not to leave your Rat Terrier Chihuahua Mix alone for too long because they can exhibit negative behaviors such as chewing on things at home and destroying furniture. Although they love to play, you can’t force a Rat Terrier Chihuahua Mix to play whenever you want. These dogs dictate when they want to play and they will let you know. When they aren’t playing, Rat-Chas love to snuggle with their owner and act like the perfect lapdog. The ideal home for a Rat-Cha is a home that has a warm or controlled climate, has no other dogs, and has no small children.

Aside from being playful and high-energy, Rat-Chas are also highly intelligent dogs. They’re easy to house train and enjoy learning tricks. Thanks to its intelligence, you will find that your Rat Terrier Chihuahua Mix will always find new ways to please you.

What Does the Rat Terrier Chihuahua Mix Look Like?

Since it is a designer breed, the Rat Terrier Chihuahua Mix can have various looks. The variation in appearance is because both the Rat Terrier and Chihuahua can have plenty of variations in their looks as well. The definite traits that you can expect in your Rat Terrier Chihuahua Mix are a small build and a soft and sleek coat.


Rat-Chas normally have small and round heads with triangular ears that point upward. They have round eyes that are prominent but don’t bulge out as much as the Chihuahua. This breed has a small mouth and tends to have an underbite.

Rat-Chas also have long bodies with thin legs and a tail that can be short to medium in length. Some Rat Terrier Chihuahua Mixes tend to have the tri-color pattern appear only in their heads while their bodies are completely white, making them look like they’re wearing a mask.


The Rat Terrier Chihuahua Mix falls in the toy or small category of dog sizes. This dog is perfectly lapdog-sized and will easily fit in a small carrier.

Male Rat Terrier Chihuahua Mixes grow up to be 10 to 16 inches tall and weigh about 10 to 15 lbs when fully grown. On the other hand, Female Rat Terrier Chihuahua Mixes are a bit smaller, growing up to just 10 to 12 inches in height and weighing about 10 to 15 lbs when fully grown.

Since both of this breed’s parents are small dogs, it doesn’t have that much variation in size. It’s rare that the Rat Terrier Chihuahua Mix is larger or smaller than the average size. If it falls outside of the average size, it’s because that its parents might be larger or smaller than the typical sizes of a Rat Terrier and Chihuahua.

F1 Rat Terrier Chihuahua Mixes, or those that are born from a Rat Terrier and Chihuahua might have more variation in size, especially if its parents are differently sized from each other. However, F2 Rat Terrier Chihuahua Mixes, or those that are born from two Rat-Chas, will definitely fall within the average size of the breed.

Take Care of a Rat Terrier Chihuahua Mix

The great thing about Rat Terrier Chihuahua Mixes is that they’re easy to take care of. Thanks to their short coats and small builds, grooming them is a piece of cake. They also don’t need much food to eat so you won’t have to worry too much about the costs of feeding your pet.

However, they are prone to several dental problems due to their parent breeds’ genes. In the following sections, you’ll learn everything you need to know to take care of a Rat Terrier Chihuahua Mix.


Rat-Chas have very little grooming needs. It’s more than enough to brush them once a week to remove any dead fur or dander. Although this breed isn’t hypoallergenic, regular brushing will help lessen the allergens that it produces. It’s best to use a gentle pin brush when grooming your dog because it will prevent any nicks or scratches.

Although the Rat-Cha isn’t prone to any ear infections, it’s still a good idea to regularly clean its ears. You should use a pet-friendly ear wipes. Simply grab one and wipe the inside of your pet’s ears once a week.

Your Rat Terrier Chihuahua Mix won’t need to be bathed very often. These dogs like to spend most of their time indoors so it’s unlikely that your pet will get into any messy accidents. It’s enough to bathe your Rat Terrier Chihuahua Mix once every few months to get rid of any unwanted odors. When bathing your dog, be sure to use a gentle pet shampoo to avoid irritating its skin.


Since the Rat Terrier Chihuahua Mix is a small dog, it doesn’t need to eat much every day. A Rat Terrier Chihuahua puppy will need about 0.16 lbs of dog food a day. An adult Rat Terrier Chihuahua Mix will need about 0.33 lbs of dog food a day. While your Rat Terrier Chihuahua Mix is still a puppy, you should divide its food into 3 to 4 meals a day. Once it reaches adulthood, you should bring it down to 2 meals a day.

Below is a table comparing different brands of dog food to feed your Rat Terrier Chihuahua puppy:

Puppy Food BrandQuantity per bagBags per yearUnit pricePrice per year
Royal Canin2.5 lbs23$21.38$492
Orijen25 lbs2$93.99$188
Hill’s Science15.5 lbs4$32.99$132
Wellness12 lbs5$42.99$215
Blue Buffalo15 lbs4$23.98$96

Below is a table comparing different brands of dog food to feed your adult Rat Terrier Chihuahua Mix:

Dog Food BrandQuantity per bagBags per yearUnit pricePrice per year
Royal Canin10 lbs12$61.78$742
Orijen25 lbs5$90.00$450
Hill’s Science15.5 lbs8$32.99$264
Wellness12 lbs10$42.99$430
Blue Buffalo15 lbs8$29.98$240

Remember that your dog’s dietary needs will depend on how you take care of it. Rat Terrier Chihuahua mixes that lead more active lifestyles may need more food than what’s recommended in the tables above. On the other hand, more relaxed Rat-Chas will probably need less. It’s best to consult with your veterinarian to figure out the best amount of food to feed your pet.

Dental Care

Both the Rat Terrier and Chihuahua are prone to various dental problems because of their small mouths. This means that the Rat Terrier Chihuahua Mix is prone to the same problems as its parent breeds. Out of all your pet’s care needs, you will need to pay most attention to dental care.

A good first step is to make sure that you regularly brush your dog’s teeth. It’s best to use a small toothbrush for your Rat-Cha because bigger toothbrushes might be able to get into the nooks and crannies of its teeth. When brushing your dog’s teeth, be sure an enzymatic toothpaste. Enzymatic toothpaste is normally flavored to taste like treats to motivate your dog to have its teeth brushed. It also easily breaks down the plaque that can cause tooth and gums problems.

If your dog is resistant to having its teeth brushed, you can instead try using a teeth cleaning chew toy. Simply fill it up with your dog’s enzymatic toothpaste and let your dog chew on it to its heart’s content. Ideally, your dog’s teeth should be brushed once a day to make sure that its teeth stay strong and healthy.

You can also supplement brushing your Rat Terrier Chihuahua Mix’s teeth by providing it with water additives. A Water additive is a solution that gets rid of puppy breath and helps your dog fight off tartar and plaque in its teeth and gums. Simply pour a capful of the solution in your dog’s water bowl every day.

Health Issues in Rat Terrier Chihuahua Mixes

Like most designer breeds, the Rat Terrier Chihuahua can be prone to any of the health issues that its parent breeds face. You will want to consult with your breeder to rule out all the possible health issues that your dog might have. The following sections will discuss some of the most common health issues that Rat Terrier Chihuahua Mixes face, how you can identify them, and what you an do to treat them.

Below are some of the health issues commonly found in Rat Terrier Chihuahua Mixes:

  1. Hip dysplasia
  2. Patellar luxation
  3. Dental disease
  4. Elbow dysplasia
  5. Alopecia

1. Hip Dysplasia

Hip dysplasia is a health issue that is common in both Rat Terriers and Chihuahuas so it is likely that your Rat Terrier Chihuahua Mix will develop it as well. If your Rat Terrier Chihuahua Mix’s parents both carry the gene for hip dysplasia, your dog will likely develop it over time.

Hip dysplasia is a condition wherein your dog’s ball and socket joint doesn’t fit correctly. This disease is most commonly caused by genes but can also be the result of poor nutrition or injury.

The symptoms of hip dysplasia include an unstable rear, sudden decreased energy or activity, decreased range of movement, a dropped back, and limping. The only way to diagnose hip dysplasia is through having your dog undergo an x-ray of its hip.

It’s important to be aware of the symptoms of hip dysplasia because the earlier that you catch it, the better the chances are for treatment. Mild cases of hip dysplasia can be treated with maintenance medication and physical therapy. Severe cases that are discovered too late will require corrective surgery to repair your dog’s damaged joints.

2. Patellar Luxation

Patellar luxation is a disease that is highly common in Chihuahuas. This makes Rat Terrier Chihuahua Mixes prone to the same disease too. Having Rat Terrier genes can help lessen the chances of your dog having this problem but if it takes after its Chihuahua parent more, it can also inherit this disease.

Patellar luxation is a health condition wherein the patella, or more commonly known as the knee cap, slips outside of the femoral grove. This condition is common among small breeds and since the Rat Terrier Chihuahua Mix is a small breed, it can easily develop this condition.

It is sometimes caused by trauma or injury to the knee but it can also be inherited through the dog’s genes. It can happen if your dog falls from a tall height or lands in an uncomfortable way when falling. According to studies done on small breed dogs, patellar luxation normally occurs along with other bone problems.

The symptoms of patellar luxation are limping, shaking the affected leg, and bow-leggedness. This disease is normally diagnosed through a physical exam or x-ray conducted on your dog’s limbs. It’s important that you get your dog checked right away if you think it has patellar luxation because it will determine what type of treatment it will need.

Patellar luxation is put on a scale of 4 grades that describe the severity of the condition. Grade 1 patellar luxation can be treated with physical therapy and maintenance medicine. Dogs with grade 2 to 4 patellar luxation will need to undergo surgery to repair their knee cap.

3. Dental Disease

As mentioned earlier, the Rat Terrier Chihuahua Mix is prone to dental diseases because of its small mouth. Dental disease is caused by plaque and bacteria buildup in your dog’s teeth and gums. Most dogs over the age of 3 years old experience some form of dental diseases in their life.

The symptoms of dental disease include yellowing in the teeth, bad breath, and swollen gums. You can also tell that your Rat Terrier Chihuahua Mix has a dental disease if it seems to be in pain while it eats. There are a variety of dental diseases that your Rat Terrier Chihuahua Mix can have, depending on its diet and genetics.

The good news is you can easily prevent dental disease by regularly brushing your dog’s teeth. You can also use enzymatic toothpastes and water additives. However, even with these preventive measures, it’s still a good idea to take your dog to the vet for a dental exam at least twice a year.

If your dog has plaque buildup, your veterinarian can take care of it by conducting a dental cleaning. When a dog must undergo dental cleaning, it will need to be put under anesthesia for the procedure. Make sure to get your Rat Terrier Chihuahua’s blood tested to ensure that it is suitable for anesthesia and to know what dose is right for your dog.

4. Alopecia

Alopecia is a condition wherein your dog lacks fur in areas where they are normally present. If your dog experiences excessive loss of fur or has multiple bald spots, it might have alopecia. Alopecia is normally a symptom of an underlying problem in your dog’s skin that needs to be treated.

Alopecia can be congenital, meaning that your dog can be born with it, or it can be acquired. Congenital alopecia may or may not be inherited from the dog’s genes. It is normally caused by a lack of normal development in your dog’s hair follicles.

If the alopecia is acquired or developed, you will need to find out what’s causing your dog’s alopecia. For these cases, it can be problems like allergies, stress, anxiety, or poisoning. Alopecia can sometimes be inflammatory and cause irritation in your dog’s skin.

The symptoms of alopecia include bald spots, sudden fur loss, excessive itching, and redness in the skin. To properly diagnose the alopecia, your dog will need to undergo a physical exam to rule out causes of fur loss. Your vet will look for other signs of skin infections such as fleas, mites, and lice.

It the physical exam is unable to diagnose the cause, your dog will then have to undergo some lab tests. These lab tests will determine if the alopecia is caused by bacteria, fungi, or yeast infections. If the lab tests are still inconclusive, your dog will need to get a blood test.

Once your veterinarian determines the cause of your dog’s alopecia, they will be able to prescribe the appropriate treatment. Treatment will depend on what is causing your dog’s fur loss. For example, bacterial or parasite causes can be treated with medicine, changes in diet, or changes in shampoo. It’s important to know that alopecia cannot be treated overnight and that you must be responsible and patient with treating your dog.

Final Thoughts

The Rat Terrier Chihuahua Mix is an adorable little dog. Despite their small statures, these dogs have large personalities. I think it just goes to show that even the smallest dogs can have the biggest hearts. The most interesting thing about the Rat Terrier Chihuahua Mix is its tendency to form a strong bond with a specific person from its family.

As someone who’s always lived with more than one dog, I know what it’s like to be a certain dog’s favorite. It can be such a great mood booster to know that your dog loves you a little more than it loves anyone else. If you’re looking to have a dog that makes you feel special, then the Rat Terrier Chihuahua Mix is perfect for you.

However, even though it is a designer breed, it’s important to know the different kinds of health problems that the Rat Terrier Chihuahua Mix has. Most of the problems it faces are conditions that can’t be treated easily. These dogs will need owners that have the time, effort, and resources to provide it with its needs. Most owners tend to be overwhelmed with the challenges of having a dog that’s prone to a lot of health problems, but even dogs that have illnesses deserve to be loved and cared for.