By John Travis
Smaller than bacteria, some of them look like microscopic spacecraft. You can find them almost anywhere: under a rosebush or miles out to sea. These strange entities are bacteriophages, viruses that prey upon bacteria, and there’s a staggering number of them. A pinch of soil or drop of seawater, for example, contains many millions of bacteriophages.
“They’re nature’s most successful experiment,” says Marisa Pedulla of the University of Pittsburgh. “They outnumber all the bacteria, all the humans, whales, trees, et cetera, put together.”