World Jellyfish Day

World Jellyfish Day celebrates this invertebrate that populated Earth’s oceans for millions of years.

Interestingly, despite its name, the jellyfish isn’t actually a fish. While a fish’s anatomy centers around its spine, jellyfish don’t even have a spine. In fact, jellyfish don’t have gills, a brain, heart, bones, or blood. Instead, a jellyfish is made up of 95 percent water.   Jellyfish do have skin through which they absorb oxygen and  jellyfish swim by contracting and relaxing the muscles around their body or bell.