Science doi:10.1126/science.1155725 (2008)

How particular to humans are the microbes that eek out a living in our intestines? To find out, Jeffrey Gordon of Washington University School of Medicine in St Louis, Missouri, and his colleagues compared particular genetic sequences from gut microbes found in the faeces of 106 mammals, some wild and others from American zoos.

Among the 60 species represented in this sample, carnivores tend to have a less diverse internal flora than omnivores, and omnivores less than hervibores. Modern humans support similar gut microbes to those of other omnivores — a surprise, maybe, given the importance of agriculture and cookery in human ecological history.