At first glance, jellyfish may be so alien-looking to the human eye that it is hard for us to even think of them as animals. Jellies are an exceptionally old species. Fossils discovered in Utah in 2007 now indicate that jellyfish may have undulated their way across ancient seas over 500 million years ago. Surprisingly, they have changed relatively little in all that time. The Moon Jelly is one of ten nearly identical jellies in the genus Aurelia. In fact, the Moon Jelly and its relatives are so similar that you cannot tell them apart without taking a sample of their DNA. All of these jellies measure approximately 10 to 16 inches (25-40 cm) in diameter with thin tentacles that hang from below their nearly translucent bodies.
Like other jellies, these have the ability to deliver a sting through these tentacles, a feature which allows it to immobilize its prey such as plankton and mollusks. The sting causes little discomfort to humans, however, aside from producing a slight rash that will disappear after a few hours. If you wander the Oregon beaches after a storm, you will often find Moon Jellies washed up on shore.
Found throughout most of the world’s oceans. They prefer the waters just offshore, staying close to the sunlit surface.