Researchers at NYU's School of Medicine just released a study of a large group of species with whom we are all intimately connected...but of whom we are also mostly unaware. Dr. Martin Blaser and his colleagues have identified about 182 species of bacteria that live on human skin, and estimate that there are probably at least 250:

"In comparison," Blaser added, "a good zoo might have 100 species or 200 species. So we already know that there are as many different species in our skin, just on the forearm, as there are in a good zoo."

"Microbes have been living in animals probably for a billion years. And the microbes that we have in our body are not accidental. They have evolved with us," Blaser said.

Link: Human skin populated by veritable zoo of bacteria (Scientific American)

Previously: The Air That We Breathe

Stuffed bacteria from GIANTmicrobes.com.