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.
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“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.”