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Kangaroo farts won't save the world

Their gut microbes really aren't that special

Photo by Paul Kane/Getty Images

Scientists locked kangaroos in a room to measure their farts. In theory, this was to see if their guts contained bacteria that might reduce methane emissions if placed in other animals’ guts; in reality, this was done because there isn’t much else going on in Australia.

For decades, scientists thought that kangaroos produced very little methane — a greenhouse gas — when they farted. Because cows and pigs are responsible for a large portion of global greenhouse gas emissions, researchers figured that this might be able to harness the power of kangaroo fart production for the greater good. To do that, researchers suggested that kangaroos might have low-methane-emitting bacteria in their guts — bacteria that might be better for the environment than the super gassy bacteria that you find in cow guts. If that were the case, then scientists might be able to transplant those microbes in livestock to make them fart less. That, in turn, would help cows and pigs produce less methane, thus slowing climate change. The plot was both clever and ridiculous, and now it's been blown to bits.

This week a study of kangaroos passing gas revealed that kangaroos emit about the same amount of methane as other animals their size. That means that kangaroo guts probably don't contain special planet-saving gut microbes. And somewhere, an Australian researcher is weeping.

Kangaroo farts won't save us from ourselves

It's sad news, but that shouldn't stop anyone from basking in the weirdness of this study, published in the Journal of Experimental Biology. Just think: to arrive at this conclusions, scientists had to put kangaroos — 10 in total — in sealed rooms. Then, the scientists fed them different amounts of food, and measured the gases that they emitted in the air. The researchers also collected kangaroo poop to figure out how many nutrients were left behind (gut bacteria strip food of their nutrients when they break it down into methane).

The researchers discovered that kangaroos really do produce less methane than cows. But when the researchers looked at the amount of methane that kangaroos emit in relation to the amount of food that they eat, they found that kangaroos and other herbivores aren't all the different. So, kangaroo gut microbes probably aren't more environmentally friendly than those you'd find in a cow or a pig. Sorry, Skippy.

That wasn't all the researchers found, however. As it turns out, kangaroos emit more methane when their food takes longer to digest. So, it's possible that cows might produce less methane if they digested food as quickly as kangaroos tend to. If that turns out to be correct, then breeding cows with fast digestive systems might be the planet-saving plan we've all been hoping for.

Or, you know, we could just regulate oil and gas emissions more strongly. Whatever works.