Regulating greenhouse gas emissions is one of the key tasks for humanity for 21st century. However, some of the sources of these gasses are rather peculiar – cows are accountable for a large portion of methane emissions. Now scientists from the University of Zurich and Australia have found out why kangaroos expel less methane than a cow.
Ruminants, such as cows and sheep, produce 20% of the world’s methane emissions. However, some of them produce much less. Kangaroos also have a foregut, where bacteria break down the plant fibres and produce methane, but produce much less of these gasses than cows. Scientists thought that it is so because of a different intestinal flora composition, but in order to understand the actual causes better, a study was conducted.
At first scientists measured how much methane kangaroos emit per food intake. This is an important ratio, because considering methane emissions per body size, kangaroos produce about as much as horses or ostriches, but when consumed food is added into equation the amount of methane kangaroo produces is closer to the ruminants. This means that the digestion process of a kangaroo is not that different than that of a cow.
Interestingly, scientists found some variations in methane production from day to day. Adam Munn from the University of Wollongong, said: “if the animals eat less, i.e. the food remains in their foregut for longer and the bacteria have more time to digest, they produce more methane per food intake”. Therefore, scientists made conclusion that different methane emissions are not because of the exact type of these bacteria, but because of conditions these bacteria are exposed to.
Normally, kangaroos digest faster than cows, which got scientists thinking if it is possible to bread cows so that food would not stay in the rumen for as long. This would be a way to combat methane emissions, although it is still not known how to achieve that. It is very important to lower methane pollution, because it aggravates the greenhouse effect and aids global warming.