Do animals fart? © Ethan Kocak

Do animals fart?

We are all prone to passing a little gas, but there is more than a delicate whiff of flatulence facts floating around some of our stinky friends in the animal kingdom.

Do ferrets fart? Can a python pass gas? Is it more than just rainbows that emanate from a unicorn’s derriere? Such questions have been troubling flatulence fans for generations, and are now definitively answered (for the most part) in the new, imaginatively-titled book by Nick Caruso and Dani Rabaiotti, Does it Fart?. Here’s a few fart facts from a book that definitely doesn’t hit a bum note from start to finish:


Do rabbits fart?

YES – Rabbits are described as non-ruminant herbivores, which means that while their diet consists of plant matter such as grass, flowers, as well as twigs, they do not have a specialised stomach to digest plant material. Instead, they rely on microorganisms (bacteria and protists) within their caecum (a pouch in their large intestine: you have one too) to extract nutrients from their cellulose-based diet. Since their food is initially digested in their large intestine, in order to get the most nutrition out of their food rabbits also reingest their cecotropes, which are soft faeces consisting of the fermented plant material.

Unsurprisingly, both the rabbit’s slightly disgusting diet and their digestive system provide the perfect recipe for farts. Rabbits not only can and do fart, but they need to fart. Stress, dehydration and a diet that is low in fibre but high in carbohydrates and sugar can lead to a build-up of gas within their intestines, which is known as intestinal stasis. While farts are often humorous, this is no laughing matter for rabbits, as this gas build-up is extremely painful and can become fatal very quickly unless properly released, sometimes requiring medical intervention.

Do birds fart?

NO – The class Aves contains nearly 10,000 species of birds, which can be found on all seven continents and range in size from the ostrich (2.8 metres) to the bee hummingbird (5 centimetres), but none of them fart! Birds don’t have the same gas-producing bacteria in their gut that are found in mammals and other farting animals, and food passes quickly through a bird’s digestive system, which leaves no time for the build-up of toots. All the necessary anatomy is in place, though, so it is likely they could if they ‘needed to’.

Although some people claim to have heard or maybe even have seen a bird fart, there are good alternative explanations for these phenomena. So far the only scientifically documented record of a potential bird flatus comes from the thesis of a Cornell graduate student, Alan Richard Weisbrod, who, in much detail, recorded the behaviour of the blue jay (Cyanocitta cristata). He noted that on a cold day in December 1963, one of his study birds’ defecation was accompanied by a ‘small puff of whitish gas’ which wafted ‘below and parallel to the slightly raised tail’ and then quickly dissipated; he also noted a second possible bird fart several days after his initial sighting. Unfortunately, this was likely just warmer water vapour from faeces meeting the cooler air and producing the visible gas.

Do spiders 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 whilst 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.

Does it Fart? by Nick Caruso and Dani Rabaiotti is out now (Quercus, £9.99)
Does it Fart? by Nick Caruso and Dani Rabaiotti is out now (Quercus, £9.99)