One of these things is not like the others.

When a Great Dane in Colorado gave birth to a litter of pups, her owner couldn’t believe her eyes: Most of the newborn dogs looked normal, but one of the small animals had green fur.

“It was so shocking when she was born," Caddy Williams told KRDO. "Luckily, I had recently read an article about a green dog. So at least I knew what was going on."

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Williams initially thought the puppy had dark, black fur, the New York Post reports. She later realized, however, that the fur was actually green, a highly unusual color for any dog.

“It was dark," Williams said of her initial assumption. "So I finally got out my phone flashlight -- and she was green!"

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While the pup’s unique hue might look adorable, it possibly has a gross cause.

A chemical found in bile, called biliverdin, could be responsible for dying the pup’s fur green, the New York Post reports. Apparently, the chemical can be present in the womb and could alter the coloring of the animal.

Fortunately, the condition isn’t dangerous in any way. It also isn’t permanent and will reportedly fade away over time.

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Regardless of its color, having a dog can actually be good for the owner's health. Certain studies show that canine companions could actually help you live longer — especially if you’re a stroke or heart attack survivor who lives alone.

The research, published in Circulation: Cardiovascular Quality and Outcomes, a journal of the American Heart Association, was based on one study and a separate meta-analysis.

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Using data from the Swedish National Patient Register, the Swedish Kennel Club and the Swedish Board of Agriculture dog registers, researchers studied residents aged 40-85 who experienced a heart attack or stroke from 2001 to 2012. They then compared the “health outcomes” of those who owned a dog and those who did not. (Of the 182,000 heart attack survivors studied, 6 percent owned a dog. Of the 155,000 stroke survivors studied, 5 percent owned a dog.)

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By the end, researchers determined those who suffered a stroke or heart attack and also owned a dog had a significantly lower risk of death from a heart attack or stroke compared to those who did not own a dog.

Fox News' Janine Puhak contributed to this report.