Perhaps the most surprising thing to be found in the new book Does It Fart? The Definitive Field Guide to Animal Flatulence is that not all mammals do.
Dogs do—and often get blamed for it when they don't. Gorillas do, anywhere they want. Horses do, including the legendary thoroughbred Hoof Hearted, whose name took on new meaning when the track announcer made his excited call. Hyenas do, and it smells really bad, for reasons you can probably sniff out, after they've eaten camel intestines, according to the book. So I would have bet a box of baked beans that all us members of the class Mammalia shared this fetid feature. But sloths don't. And it's not that they do it so slowly nobody notices.
The gut flora of sloths produce methane from the animals' leafy diets—and lots of it. But as authors Dana Rabaiotti and Nick Caruso note, “it is absorbed through the gut and into the bloodstream before being breathed out.” Yet another good reason why sloths should not light their own cigarettes.
Let's take a wind break to examine how this book bubbled into being. The author bios explain that Rabaiotti “is a zoologist currently studying the impact of climate change on African wild dogs ... at the Zoological Society of London.” (Yes, African wild dogs fart.) She is also affiliated with University College London. Which is ironic, as that institution was home to scientists who discovered five noble gases.
Caruso “is an ecologist ... at the University of Alabama, where he studies the role of climate in population biology of Appalachian salamanders.” We also learn that “while researching the various animals for this book, he has found a new appreciation for farts.” (More research is necessary to determine if salamanders fart, as they “may not possess strong-enough sphincter muscles to create the necessary pressure for a definitive flatus.”)
In the introduction, we read that one day Rabaiotti was asked by a relative if snakes farted. She realized she didn't know. So she contacted David Steen, a snake expert at Auburn University. He tweeted back at her, “<sigh, yes>.” The sigh was because the question was actually quite common—which became obvious as scientists on Twitter revealed that they, too, had been queried as to the flatus status of their study animals.
Quickly awash in information, Caruso created the #DoesIt Fart hashtag, “and, in the true nature of science, this swiftly spawned a spreadsheet.” Caruso and Rabaiotti chose 80 animals, expounded on these organisms and their gaseous habits, threw in some charming drawings by artist Ethan Kocak (whose work has appeared on the Scientific American Web site), and loosed Does It Fart? upon an unsuspecting world.
The answer to the title question for most entries is a resounding “yes.” The very first critters considered, herring, include a couple of species that “have taken the art of farting to new depths.” They gulp air at the water's surface, store it in swim bladders, and expel it from anal ducts in fast repetitive ticks (FRTs)—fart dots and dashes, which they may be using to communicate. Think Samuel Morse after an especially fiber-rich dinner.
A species of insect commonly known as the beaded lacewing produces larvae that stun and kill their termite prey (yes, by the way) by farting a chemical that induces paralysis. The authors don't mention if the fart is silent, but it's definitely deadly.
The entry for whales begins, “As you can imagine,” which I'll let you do. Giraffe farts take place, according to the spreadsheet, “at 'face height' of the average man.” But what merely average man would be right behind a giraffe? Skunks fart because it would be a cruel joke if they didn't.
The book does list a few noes, such as sea anemones, sea cucumbers, Portuguese man-of-wars (or is it men-of-war?), goldfish (unless they are having digestive issues), octopuses, soft-shelled clams and the 10,000 species of birds. Nevertheless, parrot owners have reported what sound like loud expulsions coming from their birds. But keep in mind that parrots are excellent mimics.