How Big Is A Dog’s Brain?

The brain size of a dog varies based on the breed and size of the dog. Generally, a dog’s brain is around 2.5% of their total body weight.

For instance, a small breed like a Chihuahua will have a brain weighing around 40 grams.

Whereas, larger breeds like German Shepherds can have brains that weigh upwards of 72 grams. But it’s important to remember that brain size doesn’t necessarily determine a dog’s intelligence.

Last Updated on September 20, 2023

Have you ever wondered how big your dog’s brain is and how they work? I have. And apparently, I’m not the only one who’s wondering either. Countless studies have been carried out to try and answer what exactly goes on in their minds. Let’s see what these studies have to say, shall we?

Terrier mix dog

Human brain vs. Dogs brain

Many of us have seen a human brain in pictures and in Science books. But only a number of us have seen a dog’s (or you can just search it on Google images). But exactly how big is a human brain compared to a dog? Put your two clenched fists together. That is roughly the size of a human brain. The human brain weighs on average around 3 pounds with a length of around 15 cm. long. It has the same structure as other mammals but is larger in body size ratio than other brains. And dog brains? 

According to an article published by National Geographic, a dog’s brain is at most the size of a tangerine. Maybe even smaller for smaller breeds. As for their weight, dogs’ brains only weigh 1/10 of a human brain. Pretty small, eh? This, however, doesn’t mean their brains are very much different from ours.

While the obvious difference is by their size, the brains of dogs do have the same structure as well. The brain regions such as the cerebral cortex, cerebellum, brain stem, amygdala, and hippocampus are still present and are functioning the same. Additionally, because dogs primarily rely on their sense of smell, their olfactory system makes up about 2% of their total brain weight. This part of the brain responsible for their sense of smell is called the olfactory bulb

Fun fact: Based on the brain to body ratio, Chihuahuas have the biggest brain out of all the dog breeds in the world.

Larger brains equal a more intelligent dog. 

Is a Great Dane smarter than a Chihuahua? Not at all! In fact, the size of the brain has nothing to do with intelligence in any form. Research conducted by the University of Arizona concluded that brain size did not predict a dog’s performance on social intelligence nor their physical and inferential reasoning ability. Like what previous scientists have concluded, brain size is only associated with cognitive performance. In an experiment using dog treats, larger dogs showed to have better short-term memory and self-control than small breeds.

Labrador Retriever

What does this mean for our pets?

Experts are still having discussions and discovering about the canine brain. But one thing for sure is that dogs can think and feel the things we do. Dogs have a hippocampus because they have to remember things and an amygdala that associates these memories to feelings of fear, excitement, and even aggression. It is because of this association of scent with memories do you find dogs sniffing out bombs and drugs. 

According to Psychology Today, our dogs have the same emotions as a two-year-old human. This means they can feel both negative and positive emotions. Furthermore, there is also evidence that dogs also experience PTSD from traumatic events. Making things more interesting, dogs also showed improvement when given human medications to treat depression and anxiety. Prozac is just one of the prescriptions used in veterinary behavioral medication. 

How about guilt? 

Many pet owners claim that their dogs show guilt when they come home to a destroyed couch. But according to an article published by Psychology Today in “Which Emotions Do Dogs Actually Experience?”, dogs cannot feel complex emotions such as guilt, pride, and shame. The guilty look most often seen in dogs is actually their fear of punishment.

Bonus question: Are dogs smarter than cats?

Sorry cat owners- it may turn out that dogs are smarter than felines. Despite the difference in the size of the brains of different breeds, dogs have 500 million neurons compared to cats that only have half the number.


A dog’s brain is roughly the size of an orange. Although there is a size difference, the brain structure of humans and dogs are the same. The same brain regions are present and function identically. Dogs process emotions and information like we do. 


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