It stays right there! If you suppress a fart, it actually just seeps out more quietly, or you might be able to hang on until the next time you are on the toilet. But sooner or later, that fart is coming out! – Luis Villazon

What foods make you fart?

Beans, beans, they’re good for your heart. The more you eat, the more you fart… or so the poem says. But why do beans make you fart, exactly?

Beans, like many other foods, contain plenty of soluble fibre. While this is great for your health, it can also make you fart – soluble fibres are fermented in the colon, rather than being digested in the intestines. This produces gas, which becomes a fart.

Other fart-inducing foods include pulses, such as lentils and peas, brassicas including cabbages and broccoli, onions, prunes and apples.

Do animals fart?

So, all humans fart – but does that mean all animals do, too? Read on to find out which are flatulent fiends and which are silent but deadly.

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. – Dani Rabaiotti

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. – Dani Rabaiotti

Do birds fart?

Birds have an anus, and so technically could fart, but to date there’s been no official evidence that they do. One theory is that they don’t need to fart like humans and other mammals because they have a faster rate of digestion – their food simply doesn’t spend long enough in their short gastrointestinal tracts to ferment and form gas.

Another theory is that birds’ guts don’t contain the same gas-forming bacteria as mammals. It’s also possible that ornithologists have missed bird farts because they leak out passively rather than in one eruption, or birds could be burping to release unwanted gas instead. – Charlotte Corney

Did dinosaurs fart?

Yes! Just like dogs, some insects, and even millipedes, dinosaurs undoubtedly would have passed gas.

Not only did Brontosaurus and Triceratops make wind, but they would have made a lot of it. So much, in fact, that it affected the entire Earth and its climate. One study found that dinosaurs’ ‘emissions’ were an important factor in keeping the planet warm and moist during the Mesozoic Era (250 to 65 million years ago).

Similarly, farts and burps shape our modern climate: emissions from livestock account for more than 10 per cent of all anthropogenic greenhouse gas emissions today. – Dr Stephen Brusatte

Read more about how the body works:

• What happens in my body when I burp?
• Why do kids throw up so much?
• What happens in my body when I vomit?