Ruminants are herbivores that regurgitate their food to re-chew it. Microorganisms in the animal’s gut break down carbohydrates into simpler molecules.
Ruminants including cattle and deer produce large amounts of methane, a greenhouse gas with an impact on the atmosphere 23 times greater than that of carbon dioxide. The production of methane by this process is called enteric fermentation, and it accounts for more than a quarter of methane emissions in the United States.
Source:LiveScience
Source: http://www.livescience.com/52680-the-role-of-animal-farts-in-global-warming-infographic.html
