Bulletin Buff Fan

Jellyfish and the Art of Growing a Backbone Tuesday, we're talking about jellyfish. Chances are you've never given them a second thought. The science writer Juli Berwald gets it, but she loves them.…

About 1,800 species of jellyfish live in the seas and oceans of the world. They are common both in shallow water and at great depths, in the tropics and in the ice of the Arctic. The smallest of them are smaller than a grain of sand, have a dome with a diameter of half a millimeter; the largest are giant numbers.