Cows give off massive amounts of methane as a by-product of their grassy diet. Kangaroos do not, despite having the same diet. Scientists are looking at that difference and hoping to find a way to combine a cool earth with hamburgers.

It's no secret that cows are destroying the world. They give people heart attacks, they graze on delicate ecosystems, and they are the second largest source of methane from human activities in the world. But they are so darn tasty. They may still stop our hearts and eat our grass in the future, but their methane emissions could go way down. And all it could take is a little messing with microbes and DNA. What harm did that ever cause?

While there are many grazers roaming the planes of the world, not all of them give off the huge amounts of methane that cows do. Some have different digestive systems entirely, while some, like the Tammar Wallaby, are just far more efficient with far less waste. Kangaroos and wallabies process food in multiple stomach pouches, the way cows do. Like cows, they let the microbes in one pouch do most of the work. Part of that microbial work is fermentation of the food, which produces a large amount of methane gas. This methane isn't just bad for the planet, it's bad for the animal. The part of the plant that gets pushed out as methane isn't digested as food. It's wasted energy.


Recently scientists isolated a type of bacteria, WG-1, that grows in the gut of Tammar Wallabies. When they analyzed the way it broke down plant matter they found succinate, a substance that isn't found in high-methane-producing ruminant guts. Researchers think that this bacteria could be the key to why the wallabies manage to be so, ah, clean-burning. They give off one fifth the methane that cows do from the same amount of plant matter.

Unfortunately, WG-1 can't be just shoved down a cow's throat and expected to make its way in that particular world. Gut bacteria are part of complex ecosystems which depend on what kind of material the animal takes in, what other kinds of bacteria are in there, the animal itself, and a host of other biological factors. In order to make cows as efficient as wallabies, scientists essentially have to find a way to create a wallaby's stomach ecosystem inside a cow. Still, in a world that faces warming skies and a possible food shortage, taking methane production by farm animals down 80 percent while increasing the amount of nutrition a cow gets from each bite might be worth a little hassle.

Read the full scientific paper via Science


Images: Dr. Franz Fischerleitner and Worth1000