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."
Note: To comment, Science News subscribing members must now establish a separate login relationship with Disqus. Click the Disqus icon below, enter your e-mail and click “forgot password” to reset your password. You may also log into Disqus using Facebook, Twitter or Google.