Skipper is an adorable and healthy puppy. But, what makes this Border Collie-Australian shepherd mix dog different is that it has six legs.

Veterinarians at Neel Veterinary Hospital in Oklahoma, where the puppy was born, call Skipper a "miracle."

"She has survived longer than we suspect any other canine has (at just 4 days old - published research does not indicate one has been born alive) with her combination of congenital conditions," the hospital wrote on its Facebook page Sunday.

Skipper was born naturally on Feb. 16 when Oklahoma was hit by a snowstorm. Dr. Tina Neel, the owner of Neel Veterinary Hospital, said it was born along with eight other puppies. The pup was brought to the hospital by its owners after it was rejected by its mom, CNN reported.

"Our doctors knew that we needed further imaging to determine a diagnosis so we donated the service of an abdominal ultrasound," Dr. Neel told CNN.

"The ultrasound, along with radiographs, showed that she had two types of congenital disorders, called monocephalus dipygus and monocephalus rachipagus dibrachius tetrapus, which means she has one head and chest cavity but two pelvic regions, two lower urinary tracts, two reproductive regions, two tails, and six legs, among other things," said Dr. Neel.

The vet thinks this is because Skipper was "going to have a litter mate but they did not separate in utero".

The puppy also shows signs of spina bifida along her spine. "Positively, her organs appear to be in great shape, she is peeing and pooping, and is very strong! She nurses well and is growing appropriately so far. All of her legs move and respond to stimulus just like a normal puppy," the post read.

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Skipper may need physical therapy and assistance with mobility as it gets older.

"We think that she may have some things to overcome, but she is determined right now and thriving. Our veterinarians and her family don't see any reason not to give her the best chance a great life," Dr. Neel said, adding that they "continue to research her conditions, monitor her development during rechecks."

They have also chronicled Skipper's journey on another Facebook page, which already has more than 20,000 followers.

Representational image Getty Images/Koichi Kamoshida