Depending on your point of view, jellyfish are either a threat, a thing of beauty or an unimpressive sac of goo. Juli Berwald fills in our otherwise transparent picture of jellyfish and their mysterious ways in her new book, "Spineless: The Science of Jellyfish and the Art of Growing a Backbone." Among jellyfish's notable traits: they can age both forward and backward and they produce some of the world's deadliest toxins. Tell us -- what have you always wanted to know about jellyfish?
Dr. Juli Berwald, author, "Spineless: The Science of Jellyfish and the Art of Growing a Backbone"