According to the London Guardian, Scientists in New Zealand have determined that each of the nation's 3.7 million sheep emit almost 5 gallons of methane a day, which some scientists claim contributes to global warming. They determined this in two ways. First, a team of scientists built a tower downwind from a herd of sheep, which they equipped with sensors to measure wind, temperature, and methane emissions. Second, scientists outfitted individual sheep with sensors that fit over their snouts, from which the sheep release 98 percent of the methane they emit. There were no plans to affix sensors to the other end of the animals, from which the remaining 2 percent of gas is passed.

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