Hoo, doggies! Why does cat poop smell so bad?

Well, the easy answer is, because it’s poop.

And for years, people have explained it away with the same possible causes: diet, digestive disorders, or the presence of parasites.

But what about those times when the smell is really bad?

Japanese researchers discovered the answer in a new study published this month in the Journal of Chemical Ecology.

That horrible smell comes from sulfur compounds. Which should come as no big surprise to anyone who has ever had the bad luck of smelling a rotten egg.

Masao Miyazaki, PhD, DVM, an associate professor of biochemistry at Iwate University in Japan and lead author of the study, said the specific source of the smell is an organic sulfur compound that’s similar to a pungent ingredient in white wine.

It’s worth noting here that the smell of white wine is often compared to the smell of cat urine. (although for what it’s worth, many wine enthusiasts believe the aroma of cat pee can help identify a high-quality Sauvignon Blanc.)

It took some sorting on the part of the researchers.

A variety of stinky components are present in cat poop, but the researchers were able to eliminate fatty acids and other unpleasant-smelling substances that are also contained in the excrement of animals other than cats to single out the malodorous material that is specific to the feces of felines.

His team successfully identified that material’s chemical structure as 3-mercapto-3-methyl-1-butanol (MMB), which is a derivative of felinine, a sulfur-containing amino acid found in cat urine. It’s found in especially high concentrations in the urine of intact male cats, has been linked to pheromones, and is thought to play a role in marking territory.

MMB emission levels in feces differed between males and females, with higher levels found in male droppings than in female.

Lead author Miyazaki concluded that their breakthrough findings could lead to the further development of technologies designed to reduce feline poop odor. Although Miyazaki said a lot more research is needed before products based on their research could be brought to market, he did have a down and dirty short-term tip: Cat feces can be partially deodorized by soaking them in water that contains ions of metal, such as copper.

Interestingly, the researchers also found that the same sulfur compounds found in cat feces were noticeably absent from dog feces.

Which is not to say that dog poop smells good, but it would explain why it generally smells better than cat poop.

Although, to be fair to cats, no one ever compared the nose of a really good Pinot noir to the smell of dog pee.

Photo credit: © iStock/kMickey

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