Dog Brain Size: How Big Is a Small Dog’s Brain?

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Whether your pup is highly intelligent or a bit of a slow learner, you may have wondered about your dog’s brain size. After all, their brains are quite different from those of humans, but canines are still clever. So, how big is a small dog’s brain? The beagle, a small hound, has a brain that weighs about 2.54 ounces, or 72 grams, on average.

So, how big is a medium-sized dog’s brain? Or a large-sized dog’s brain? While brain size differs from breed to breed, dogs usually have a brain-to-body mass ratio of 1:125. On average, for every 125 ounces, a breed gains an ounce of brain mass, so smaller breeds naturally have smaller brains.

However, it is important to note that brain size does not increase linearly with body size. Because of this, the 1:125 ratio does not hold true for breeds that are extremely large or extremely small. Smaller dogs have slightly larger brains than expected in proportion to their bodies, while larger breeds have larger brains that are slightly smaller than expected based on body weight.

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