Why Birds Don't Fart

A duck, a dog, and a human walk into a bar. One of them passes gas. Who's the most likely suspect? According to experts on the matter, at least one of the trio can be eliminated as the likely source of the offending smell. It's the duck.

Answering the question that more than a handful of people have wondered about (judging by the number of google searches, articles, and yes, videos) birds are not known to fart. Veterinarian Mike Murray, who works at the Monterey Bay Aquarium in Monterey, California, told Popular Science that birds could if they wanted to — they're physically and anatomically put together in such a way that allows them to do it — but he says they don't need to. "... if I saw gas in a bird's gastrointestinal tract on an x-ray, I'd suspect that something abnormal was going on in there," he told Popular Science.

To understand why birds don't fart, you have to understand a little about why any creature farts. Technically known as flatulence, farts are simply the expulsion of gas from the digestive system through the southern route, as it were. (Sometimes it's referred to as "a back-door burp.") Gas collects in the body as the result of breaking down food, or swallowing air via eating or drinking, according to Healthline.

Birds have shorter digestive tracts than many mammals, including humans, and that gives them the ability to digest food much faster, according to BirdFact. In fact, they digest food so quickly that some birds poop every 5 to 15 minutes. The speedy process from ingestion to exit essentially prevents the formation of gas. Birds also don't have the same type of bacteria in their digestive systems that humans and other animals do. It's that bacteria that aids in gas formation, according to Popular Science.

Back to the trio in the bar — the dog, the human and the duck. We know dogs and humans fart (humans fart up to 25 times a day, according to MedicalNewsToday). As do almost all other mammals including seals, and orangutans (but not sloths), according to Vox. Snakes and fish also pass gas. Apparently, so many people are fascinated by the subject that there's even a book to answer the question. The 2017 book "Does It Fart?: The Definitive Field Guide to Animal Flatulence" explains which animals fart and even how those farts smell. In case you were wondering: millipedes fart, spiders might, and even dinosaurs did, according to the book.

While birds do not fart, they are capable of burping, according to Popular Science, though there's no documented evidence of a bird doing so. Yet, experts say that birds do excrete a lot of things from their mouths (think regurgitating food for their chicks), so it wouldn't be surprising.