Methane found in cow flatulence has become a major cause for concern as climate change becomes an important issue, but new research suggests kangaroos aren't as gas-free as we thought.
In the past scientists believed kangaroos and wallabies produced much less methane than other ruminants, but new research suggests this is not necessarily true, the Journal of Experimental Biology reported. Kangaroos' lack of gassiness was attributed to the presence of a unique microbe, called Archaea, present in the animal's foregut.
"The idea that kangaroos have unique gut microbes has been floating around for some time and a great deal of research has gone into discovering these apparently unique microbes," said Adam Munn from the University of Wollongong, Australia.
Munn also noted the fact that kangaroo's and wallabies produce very low levels of methane has never been concretely confirmed. To find out once and for all, the researchers carefully measured everything that went into and came out of animals. They reported that kangaroo methane production is on par with other carnivores. The team fed kangaroos alfalfa at quantities of either a restricted diet or all they could eat to find out how it influenced the animals' methane production. The then collected the kangaroos' feces and compared it with the nutrition content of the feed to determine how much food they had digested in relation to the amount of methane they produced.
The results revealed the alfalfa-eating kangaroos produced similar levels of methane to other kangaroos of their size. The team also found the kangaroos' methane production relative to their metabolism was similar to what was seen in horses, which means they are no less gassy than most other herbivores. In the kangaroos' defense, they did produce less methane than cows. The researchers also noted the kangaroos that were able to eat as much as they wanted actually produced less gas than those on a restricted diet.
"Kangaroos are not mysteriously low methane-producing creatures, but herbivores with an active methane-producing microbe community," concluded Marcus Clauss from the University of Zurich, Switzerland.
The study was funded by the Swiss National Science Foundation.
