Fascinating Facts About Jellyfish, Part I

• Jellyfish don’t have any brain, heart, or bones. Some jellyfish have ways of detecting obstacles that can be compared to sight but they don’t have real eyes. It is a mystery how they can process the information from their “sight” since they doesn’t have any brain. They react directly on food and danger stimuli via nerve impulses without having any brain to process the impulses. Another fact about jellyfish and their bodies is that the body consists of over 95% water.
  
  Yup, the jellyfish is ugly, brainless, and heartless. Ouch!
  
  
• Jellyfish use tentacles with stinger cells to catch their prey, typically plankton and small fish. (The exact prey depends mainly on the size of the jellyfish.) The tentacles transport the prey they killed with their stingers to the mouth and the jellyfish promptly devours the animal. It is the same stinger cells that stings humans that ventures to close.
  
  
• Jellyfish are made up of an epidermis, gastrodermis and mesoglea. Jellyfish do not have a central nervous system,a circulatory system, respiratory system, or a osmoregulatory system. They have an incomplete digestive system and therefore use the same orifice for intake of food and expulsion of waste materials.
  
  So basically, they poop out of their mouths. Ewwww...
  
  
• Jellyfish go through several stages during their lifecycle and the form that you usually associate with jellyfish, medusas, is only one of them. There is for instance a phase called planula, where the jellyfish is in a type of larval stage. The planulae eventually attach themselves to surfaces where they become polyps which later turn into to medusas.
  
  
• Jellyfish swim by contracting and expanding their bodies. They do not have scales or shells. If exposed to the hot sun, they disappear, leaving only a circle of film. Jellyfish have a defense mechanism of oral arms or tentacles which are covered with organelles called nematocysts. These nematocysts are paired with a capsule which contains a coiled filament that stings. The filament unwinds and launches into the target, thereby injecting toxins upon contact by foreign bodies.
  

Stay tuned to Ugly Fish for more fascinating facts about Jellyfish!