Home Dog BreedsChihuahua Chihuahua Brain Size: Is It Bigger Than You Think?

Chihuahua Brain Size: Is It Bigger Than You Think?

by Joel
Chihuahua Brain Size: Is It Bigger Than You Think?

If you’ve ever found yourself fortunate enough to share your home with a Chihuahua, you’ve likely been amazed and perhaps a little perplexed by their undeniable character. After all, there seems to be an intriguing contradiction inherent to these little dogs: their bodies may be small, but their personalities are anything but small. Complementing this exceptional character, their brain size also plays a role that might be more significant than what you’ve ever imagined.

With so much personality packed into such a small package, it’s no wonder that Chihuahua owners often ponder the size of the Chihuahua’s brain. Despite their tiny stature, these dogs behave with confidence and sass that many larger breeds lack. But how does a Chihuahua’s cerebral size compare with their body size? And how does this juxtaposition affect their behaviour, learning, and memory?

In this article, we’ll be exploring these captivating questions, delving deep into the curious world of the Chihuahua and the remarkable pint-sized brain that powers their vibrant personalities.

Average Brain Size For a Chihuahua

The average adult Chihuahua weighs between 2 to 6 pounds, making them one of the smallest dog breeds globally. Despite their petite physique, Chihuahuas possess a relatively large brain for their size. Their cranial volume is estimated to range from 36.4 cm³ to 41.3 cm³, positioning them uniquely in terms of the ratio of body size to brain size, commonly called the “encephalization quotient.”

Although a Chihuahua is significantly smaller than, say, a German Shepherd, its brain size relative to its body size is actually larger! This discrepancy is due partly to the fact that a Chihuahua’s skull is dome-shaped, providing extra space to accommodate a larger brain proportionate to their body size.

Like other small breeds, Chihuahuas exhibit higher neuronal density than larger dogs. Increased neuronal density could facilitate enhanced cognitive function and quicker processing time, likely contributing to their dynamic personalities, sharp alertness, and adaptable nature observed by owners.

Chihuahua Brain Development

The development of a Chihuahua’s brain, much like any other dog breed, is a complex and fascinating process. It begins soon after conception and continues well into their adult lives. So, let’s simplify this journey and make it easy for everyone to comprehend the stages of a Chihuahua’s brain development.

Stage 1: In-Utero Development

Brain development in Chihuahuas begins in the mother’s womb. Remarkably, the basic structures of the brain form just a few weeks after conception. During this phase, neurons are growing and making connections, laying the groundwork for all future development.

Stage 2: Puppyhood

When a Chihuahua pup is born, although their brains are not fully developed, they are capable of basic functions like eating and self-regulating their body temperature.

At about three weeks of age, rapid brain growth occurs. This is when pups open their eyes and begin exploring their surroundings. This exploration helps to stimulate and shape their expanding brains by creating new neural pathways.

A Chihuahua pup enters the most crucial socialization period from three to twelve weeks. Exposure to different stimuli, such as sounds, smells, people, and other animals, is vital during this time. These interactions significantly influence the wiring of their brains and play a huge role in their future behavior and reactions to their environment.

Stage 3: Adolescence and Adulthood

As a Chihuahua enters adolescence (around six months) and progresses into adulthood, their brain will already be fully grown. However, the brain’s ‘plasticity’ means it can continue to change and adapt. Therefore, training, experiences, and lifestyle can continually shape their brains.

What Does a Chihuahua Brain Look Like? 

Much like other canines, a Chihuahua’s brain maintains a similar structure. If you imagine your fist, this could roughly represent the overall size of an adult Chihuahua’s brain – not too big, right? Their brain is encapsulated in a characteristically dome-shaped skull, which provides extra housing space for the cerebral hemisphere compared to other breeds.

  • Forebrain: This is the front part and the biggest piece of the brain puzzle, embodying the cerebral cortex and basal ganglia. Picture a large walnut – wrinkly and full of intricate patterns. This area is responsible for everything that makes your Chihuahua such a unique character, like learning, problem-solving, and expressing their emotions.
  • Midbrain: The midbrain acts as a relay station, kind of like the postal service of the brain, transferring messages from one area to another. It plays a significant role in motor movement, particularly movements of the eye, and regulation of auditory and visual processes.
  • Hindbrain: This part of the brain, also known as the “reptile brain,” is responsible for more instinctual behaviors like maintaining balance and motor coordination. Think of it as the autopilot section of your Chihuahua’s brain, taking care of the tasks that your pet doesn’t have to consciously think about.

Can Chihuahuas Have Brain Disease? 

While Chihuahuas are vibrant, entertaining bundles of joy, they, like any other breed, may encounter certain health issues throughout their lives. Among these health concerns, brain diseases deserve special attention due to their potential implications on a dog’s quality of life.


Hydrocephalus often referred to as “water on the brain.” This condition occurs when there’s an excessive accumulation of cerebrospinal fluid (CSF) in the brain. This can put pressure on the brain, leading to various symptoms like a larger-than-normal head size, difficulty in walking, seizures, or vision problems.

Due to their ‘molera’ or soft spot on the skull, Chihuahuas are more prone to this condition than some other breeds. While this ailment can be congenital, meaning your Chihuahua is born with it, it can also develop later in life due to trauma or infections.

Canine Epilepsy

Epilepsy is a neurological disorder that results in recurrent seizures. The symptoms could range from an unusual period of intense staring to full-blown uncontrollable muscle activity. While epilepsy isn’t exclusive to Chihuahuas, it’s one of the more common neurological disorders dogs can experience, and it can occur in any breed.

Canine Cognitive Dysfunction

Often comparably termed as the canine version of Alzheimer’s disease, Canine Cognitive Dysfunction (CCD) is a condition characterized by a decline in cognitive functions. Symptoms range from disorientation, changes in sleep patterns, house soiling, altered interactions, and in some cases, repetitive or unusual activities. Although CCD primarily affects older dogs and isn’t specific to Chihuahuas, it’s a disease that dog owners should be aware of.

Are Chihuahuas intelligent?

Chihuahuas are often recognized for their intelligence, despite their small size. Here are some details on why Chihuahuas are considered smart:

  1. Quick Learners: Chihuahuas are known to be fast learners. They can quickly pick up commands and tricks, making them responsive to training efforts.
  2. Adaptability: Despite their tiny stature, Chihuahuas are adaptable dogs. They can adjust well to different living environments and lifestyles, whether it’s a bustling city apartment or a quiet suburban home.
  3. Alertness: Chihuahuas are inherently alert and make excellent watchdogs. Their keen sense of hearing and sharp eyesight contribute to their ability to detect and alert their owners to potential dangers or strangers.
  4. Problem-Solving Skills: Chihuahuas have a knack for problem-solving. They can figure out how to access treats from puzzle toys or find clever ways to get what they want.
  5. Social Intelligence: Chihuahuas can be socially intelligent. They form strong bonds with their owners and are often loyal companions. While they may be reserved around strangers, their social intelligence allows them to connect well with those they trust.
  6. Independence: Chihuahuas exhibit a degree of independence, often seen as a sign of intelligence. While they may have a mind of their own and can be a bit stubborn, this independence can also be a positive trait.
  7. Adaptive Problem Solvers: Chihuahuas can adapt to various situations and environments. Their ability to navigate different scenarios showcases their cognitive flexibility and problem-solving skills.
  8. Communication Skills: Chihuahuas are good communicators. They use a combination of barks, body language, and facial expressions to convey their needs and feelings. Understanding and responding to their communication is a testament to their intelligence.

Chihuahua Head Shapes

Although the overall breed standard defines certain characteristics, observable differences in head shapes warrant examination. Notably, three primary types of Chihuahua head shapes have been identified:

  1. Apple Head: The “apple head” is a widely recognized and celebrated Chihuahua head shape. This head type is characterized by a rounded and domed cranial structure, which imparts a distinctively apple-like appearance. The skull is proportionate to the breed’s diminutive size, exhibiting a gentle curvature. The apple head is often associated with a shorter muzzle and a well-defined jawline, contributing to a harmonious facial structure.
  2. Deer Head: Unlike the apple head, the “deer head” Chihuahua exhibits a more elongated and slender cranial structure. This head type has a flatter skull and a more extended muzzle. The term “deer head” is derived from the perceived resemblance of the head shape to that of a deer. The eyes are typically wider apart, and the overall expression may differ from the apple head, creating a unique and alternative aesthetic within the breed.
  3. Papple (Pear/Apple) Head: The “papple head” represents a hybrid head shape combining elements of apple and deer head types. This variation is characterized by a rounded skull akin to the apple head, yet it may feature a slightly more extended muzzle, reminiscent of the deer head. The result is a head shape that blends the distinct characteristics associated with the apple and deer head types.


Do Chihuahuas have a good memory?

Yes, Chihuahuas have a good memory! They are smart, energetic and affectionate. They don’t like to be left alone for long periods and will get bored without enough attention.
They crave attention from their owners, which makes them great family pets because they love to play with kids and other pets.

Final Thoughts

A medium-sized brain, weighing in at an average of about 16-18 ounces and roughly two to three times heavier than a cat’s brain, is about the most one would expect from a dog of its size. So, the Chihuahua’s brains are not too small.

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