Today’s Wonder of the Day was inspired by Tyler. Tyler Wonders, “What is the Tallest Dog in the World” Thanks for WONDERing with us, Tyler!

Have you ever walked down a sidewalk, heard a loud “WOOF! WOOF!” from behind a fence, and wondered just how big the barking dog is? You might imagine that they are as big as you are! But what if the dog is not just bigger than you, but bigger than a grown up? How big can a dog get, anyway?

It all depends on what we mean by “big”! Are we measuring height, weight, or length? The tallest dog ever measured was Zeus, a Great Dane. He was 44 inches tall (or 3 feet, 8 inches) from his shoulder. Dogs, like horses, are measured from the withers—where their shoulder blades meet. Zeus beat the record for the tallest dog in 2011. Sadly, though, Zeus died in 2014. In 2022, there was a new record holder for tallest dog. He is also named Zeus, and he is also a Great Dane! Many previous record holders have been Great Danes as well.

These giants can be over seven feet tall when they stand on their hind legs! But what about the longest dog? Several of the most recent record-holders were Irish wolfhounds. The most recent one was Farrell, an Irish wolfhound who was 7 feet, 9 inches long from nose to tail. The longest dog in history was even longer! He was an Old English mastiff named Zorba, who measured 8 feet, 4 inches. Zorba also likely claims the prize for the heaviest dog, although those records are not generally kept. He weighed an amazing 343 pounds.

These are individual record-breaking dogs, but which breeds are usually the biggest? The overall largest dog breeds are the Saint Bernard and the Old English mastiff. They were bred to be working dogs, and their large size was important for the work they did. Saint Bernard dogs were bred and trained to be rescuers, helping travelers in the Alps. In fact, they are credited with saving over 2,000 lives in their years of work.

Old English mastiffs were bred as guard dogs and as fighters or “war dogs.” The breed is very old—even the ancient Romans used mastiffs as fighting dogs in their arenas. Mastiffs are so large that they would be made to fight against animals like bears, lions, or tigers. Now, Saint Bernards and mastiffs are usually pets. Although mastiffs were bred to fight and guard, they are known for their gentle temperament. Saint Bernards are even known as “nanny dogs” because of their friendly nature.

As you see from the record-holding dogs, one of the tallest dog breeds is the Great Dane. Great Danes are also working dogs. They were bred to hunt boars, a kind of large wild pig. Now, of course, they are mostly pets. Another very tall breed is the Irish wolfhound. Can you guess what this working dog was bred to do? That’s right—wolfhounds were bred to hunt wolves! Like most other large breed dogs, these former working dogs are now mostly pets.

Now that you know about the biggest dogs, do you WONDER about the smallest? You may already know that the chihuahua is the smallest breed. In fact, the shortest dog—a chihuahua—is about 11 times smaller than the tallest Great Dane.

Some of these breed differences come from natural changes that have evolved over many years. It makes sense that dogs from cold climates, like huskies, have a much thicker coat than dogs that come from hot climates, like chihuahuas. Other changes have been helped along by humans. Dog owners and breeders choose certain characteristics they want their dogs to have. These might include the size, appearance, or personality.

Now that you’ve met the biggest dogs and the smallest—what kind of dog would YOU want?

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