Armpits Are "Rain Forests" for Bacteria, Skin Map Shows

Long considered a source of odor and embarrassment, the humble armpit may be coming up in the world.

On the microbial level, a person's underarms are akin to lush rain forests brimming with diversity—and that's a good thing—according to a new "topographic map" of human skin.

Most of our skin is like an arid desert, said study co-author Julia Segre, of the National Human Genome Research Institute in Bethesda, Maryland.