Guinea pigs are such funny, furry pets. So how many guinea pigs are there in the world? There were 1,362,000 pet guinea pigs in America in 2007 (that's more than a million), and another 1 million in England in 2012. There were also 30 million "small mammal pets" in all of Europe in 2010, which included mice, hamsters, and gerbils...if 1/10 of those were guinea pigs, that's another 3 million. That gives us at least 5 million guinea pigs. But they often live in pairs, so how many homes have one?