In 2017, zoologist Dani Rabaiotti’s teenage brother asked her a most-teenage question: Do snakes fart? Stumped, Rabaiotti turned to Twitter and of course, the Internet did not disappoint. Her innocent question spawned the hashtag #doesitfart and it spread like a noxious gas through the vibrant Science Twitter community. Thanks to Rabaiotti’s curious brother and the power of Twitter comes the New York Times bestseller DOES IT FART? The Definitive Field Guide to Animal Flatulence by Dani Rabaiotti, a zoologist at the Zoological Society of London, and American ecologist Nick Caruso. Illustrated by Ethan Kocak, DOES IT FART? is the ultimate guide to animal flatulence: the perfect gift, hilarious and, yes, scientifically rigorous.
Scientific Name (Species): Capra aegagrus hircus
DOES IT FART? Yes
Goats belong to the family Bovidae, which includes cows (page 102), meaning they have four stomachs packed full of methane-producing bacteria which help them digest plant material, and so give off a lot of gas in the process. Although this process produces far more burps than farts, goats do fart, and this combination makes them particularly gassy animals. In 2015, a plane full of over 2,000 goats on its way to Kuala Lumpur was forced to land unexpectedly after the fire alarm was set off by the copious amounts of gas produced by the goats on board.
Domestic goats, and their farts, have lived alongside humans for over 10,000 years, thanks to the goat’s hardy nature and milk production. One of the oldest surviving secular songs in the English language—“Sumer is icumen in,” which is about the sights and sounds of summer—includes the line “Bulluc sterteþ, bucke uerteþ,” which is thought to mean “Bullock leaps, billy-goat farts.” So it isn’t just goats that are culturally important, but their farts too.
Scientific Name (Class): Diplopoda
DOES IT FART? Yes
Millipedes get their scientific name Diplopoda from the fact that, unlike other arthropods, they have two pairs of legs on each segment of their body. Also unlike many other arthropod groups, millipedes have a very simple digestive system which lacks a pouch in their hind-gut for food storage. This means food passes through millipedes quickly and so must be broken down as fast as possible. To help, millipede intestines contain a type of organism called methanogenic archaea—single-celled microbes which assist in breaking down their food (mostly rotting wood and leaf litter), producing methane in the process.
Different species of millipede have different types of archaea in their gut, and methane production is positively correlated with body mass—that is, the bigger the millipede, the bigger the farts. As with many other groups of insects, millipedes living in the tropics are bigger than those living in temperate climates, therefore tropical species tend to produce more gas. The biggest species of millipede—the Giant African millipede, Archispiros- treptus gigas—can grow up to 38 centimeters long, with about 256 legs, and lives (and, we assume, farts) mainly in the lowland forests of East Africa.
Scientific Name (Order): Psittaciformes
DOES IT FART? No
Here’s where the science starts to get less clear-cut than you might like. As you will learn on page 57, birds do not fart. When collecting the data that went into this publication, however, there were numerous reports of farting parrots, and numerous examples of this activity can be found on the internet. So what is going on? Well, parrots are exceptionally good at mimicking sounds made by humans, as well as other animals, and even noises such as the television. One African gray parrot (Psittacus erithacus), Alex, learned over 100 words and was thought to be able to identify objects and colors. Prosecutors in Michigan in 2016 were even considering using a parrot as evidence in a murder trial when he started repeating the words “don’t shoot” after his owner was shot and killed. So the reported cases of parrot farts are more than likely “hot air”; instead, parrots are mimicking the sound of humans farting—meaning any farts you hear from a parrot are coming from their mouth, not their cloaca!
Scientific Name (Mythical): Monocerus
DOES IT FART? Yes
It would seem sensible to assume that since horses (page 10) fart, unicorns, often described as horses with a single horn emerging from the center of their head, must also fart.
The origins of the unicorn date back not to Greek mythology but actually to Greek natural history, where scholars described them as living in the forests of India. Today, it seems likely that these reports were in fact based on sightings of the Arabian oryx, Oryx leucoryx; potentially of individuals that had lost one of their horns while fighting. Oryx are part of the family Bovidae (the same family as cows, page 102), and do fart, so again it is likely that the same would apply to unicorns. On the other hand, the unicorn myth may have emerged from descriptions passed down through generations of a large ice-age rhino species, Elasmoth- erium, which had a single, large horn in the center of its head. As extant rhinos (page 24) fart copiously, we can assume that this extinct species did too. Unicorns may not exist, but if they did they would definitely fart. Scientists are still debating whether those farts would be made up of rainbows and glitter.
Scientific Name (Order): Araneae
DOES IT FART? Nobody Knows
Spider flatulence is an oddly understudied topic in scientific literature, but we can look to their digestive system for some clues. Spiders do the vast majority of digestion outside their body, injecting their prey with venom from their fangs before ejecting sputum, full of digestive enzymes, from their mouths, through the fang holes and into the body of their prey. They then wait while the digestive juices break down tissues inside the exoskeleton or, in some cases, skin of their prey. Spiders will then suck up the liquidy goodness into their mouths and stomachs, then they regurgitate it and eat it again. This happens a number of times, as spider digestive systems can only handle liquids—which means no lumps! It would seem likely that spiders ingest air during this process—one of the key elements needed for a fart.
Once they have extracted all the nutrients, in an organ called the ceaca, the food passes to the stercoral sac, where the moisture is extracted before anything left over is excreted through the anus as waste. Since the stercoral sac contains bacteria, which helps break down the spider’s food, it seems likely that gas is produced during this process, and therefore there is certainly the possibility that spiders do fart. No work has been done to verify this to date, however, so the truth remains a mystery until urgently needed research funding is allocated.