When walking around outside, as a general rule, you should probably watch where you step. You don't want to trip on a cracked sidewalk or into someone's discarded chewing gum. And you definitely don't want to step into dog poop. While most dog owners are conscientious and will pick up after their pup, not all do. And some owners let their pets run off leash around their yards or even their neighborhoods; in those cases, the dogs will go where they want and the owner isn't always the wiser. So if you're in an area with a lot of dogs, be on the lookout for leave-behinds. It's just the smart thing to do.

You probably knew that already, though -- and as a result, you've probably noticed your fair share of dog droppings in your day. And you may also have noticed the color of the dog doo: it's usually a rather unsurprising brown. That's the color poop is -- sure, it can come in varied shades of brown, but it's almost always brown. And even if you didn't notice that, you probably know enough about the stuff that you know it isn't white. (Bird poop actually isn't an exception to this; check out today's From the Archives link to learn why.) 

But for many years, that wasn't the case, at least when it came to dogs. It was very common for dog poop to be chalky and ashen white, as seen at the top. (Sorry, but the story really does need a picture of dog doo to work.) If you're of a certain age, you probably knew that already. But if you're younger, you've probably never even heard of such a thing. As Good News explains, "back in the 1970s and 1980s, it was common to see chalky, white dog poop littering yards and sidewalks." And "while dogs didn’t go anywhere, their distinct white feces started to disappear in the 1990s. Today, it’s basically nonexistent."

Clearly, something changed -- and no, it wasn't the dogs themselves. Where'd it all go?

The dog equivalent of the Tooth Fairy is to blame. This mythical creature goes around the Earth,  picking up after dogs, but only collecting the white stuff. Then, the White Doo Fairy uses all the -- no, wait, that's not right. There's nothing supernatural about this odd-colored poop, nor its disappearance. It's all about diet, and, specifically, the quality of the dog food Fido was eating.

Dogs don't usually get to choose what they eat; whatever their owners put in their bowls is dinner, and there's little use in objecting. And while we think of our dogs as family members, we probably aren't quite as concerned with what they're eating as we would be, say, for a small child. (It's close, though.) For most of the history of dog food, cheap fillers were an easy way for manufacturers to keep prices down, which most dog owners appreciated. One of the most common fillers was born meal -- basically, ground-up animal bones that would otherwise have been discarded at the slaughterhouse -- and bone meal contains a high amount of calcium. And the dogs couldn't digest all that calcium. As Mental Floss explains, "whatever the dog couldn't process ended up in its feces, and as the wet matter dried out in the sun, the hard calcium stuck around. This led to crumbly, mummified turds littering our sidewalks and green spaces." 

Unfortunately for the dogs, while white poops were harmless, the bones they came from weren't. Bone meal could contain some sharp edges and, per Reader's Digest, "dog food companies began to realize that cooked bones could splinter and damage a dog’s digestive system." No one wants to do that to their pup, so in the late 1980s and 1990s, dog food companies began using other fillers -- typically plant-based ones that are high in fiber and have virtually no calcium at all. And just like that, the white dog doo disappeared from our sidewalks.

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