The world's biggest puppy - who weighs a whopping 12 stone and stands at a staggering six-foot-tall - has been bred to replicate an extinct ancient dog .

At nine-months-old, enormous Euphrates eats an impressive eight cups of a dog food a day and plays with a piece of fence post.

She is a new breed called the American Molossus, from the first litter of selective breeding to be the closest genetic descendant of the 5,000 BC Mesopotamian Molossus .

The ancient animal was massive and fierce in appearance and they were used in war.

But the only remnants of their legend was left in museums.

She is a whopping 12 stone and on her hindlegs can reach six foot (
Image:
Caters News Agency)

After calling hundreds of breeders and Guinness World Records, owner Jared Howser, of Salt Lake City, Utah, believes he owns the largest puppy in the world.

In public people often gasp upon seeing the colossal canine and can't believe how big she is for her age, often confusing her for a fully-grown adult.

The 41-year-old carpenter who makes kennels for XL dogs , said: "It's unreal and unheard of, at nine months her size and strength is far beyond what I thought it would be.

"When she stands on her hind legs she is six-foot-tall, that's only at nine months too, on all fours to the withers, the tops of her shoulders she is 31.5 inches.

Euphrates shortly after she arrived with the family (
Image:
Caters News Agency)

"If she was to stand she is big enough to look out of the peephole on our door."

Jared says he is 260lb and is 6ft 3in tall but said if the puppy runs he could not hold on to her leash saying "she could drag me down the road with ease".

He added: "Just from wagging her tail if she catches your knees, she can take down a grown man down no problem.

"We have a pitbull who she plays tug of war with, they are known for the ability to pull more than their own weight, but Euphrates she just sits holding the other end in her mouth unaffected and not budging at all.

"When people look at her, they are surprised and asked how I've been able to keep her under control, joking that I must be a lion tamer.

Euphrates at six months old, when she was tall enough to reach the kitchen counters (
Image:
Caters News Agency)

"Most people think she is a fully-grown dog when we take her out in public, when we tell them she is a nine-month-old puppy their jaws hit the floor.

"They natural reaction is 'holy cow' or 'this is the biggest dog I've ever seen', then they want to pet her and she's very affectionate.

"At nine months there simply isn't another dog 180lbs and 31.5 inches to withers anywhere else in the world, she is an anomaly.

"We've looked up online and called the Guinness World Records, reached out to hundreds of breeders to see if any dog comes closer to her size for this age and there's nothing."

Euphrates and teen son Shakespeare (
Image:
Caters News Agency)

Euphrates cost $5,000 (£3,600) and was the largest of the litter.

So far she has had two growth spurts that took place over a couple of weeks each time.

Jared says that her vast alteration in size over a short period of time left her clumsy as she was having to readjust to her size on a daily basis.

He said: "She had two growth spurts, in that time period she was so clumsy because she was getting vastly bigger every day.

"I never expected that she would be this big when we first brought her home, at four and a half months old she was already 10 stone.

"By six months old she was tall enough to reach the kitchen counter while sitting down."

Jared started looking for a larger dog after witnessing a home invasion, where traumatically he watched as a burglar throw a 9st 4lb Cane Corso dog out of a window to its death.

Zorba the mastiff, who is a huge dog, looks ting compared to Euphrates (
Image:
Caters News Agency)

After consulting with a breeder, he was told about the American Molossus breeding programme and would go onto become one of the first to adopt one.

Jared said: "The Molossus of ancient Mesopotamia was a magnificent animal. With a black brindle coat as dark as the night and a massive build, they were fierce in appearance.

"These dogs made men tremble at their sight. With a profound sense of loyalty, these giants would defend against any man or beast that threatened the safety of their masters.

"The only two direct lines coming from that ancient dog are the English and Neapolitan Mastiff.

"Through selective cross-breeding those two breeds it's given us the closest living relative to the ancient breed that we now know as the American Molossus, a bona fide relic from the ancient past."

She plays with her block of wood as twigs are too small (
Image:
Caters News Agency)

Since bringing Euphrates home, he claims that every other car apart from his own, in the neighbourhood has been broken into.

Despite being a natural protector and an intimidatingly sized pup, in public the mountainous Molossus is very friendly, gentle and caring,

Jared said: "The hope is to avoid any violence, she is a big scary dog, I live in a good area but we are the only house on our block not to have had our car broken into since having Euphrates.

"She is gentle but her guardian nature is very good too, we've made little tests by making sounds at night and she investigates every single one.

"She is very affectionate with us, when we take her out in public she is very affection with children and women especially.

"If anyone reaches out a hand to stroke her, her tail will start wagging, if you don't look her in the eyes she will be friendly but will posture against you."