BIO 203



So I bet you’re all wondering, “how on earth does an animal the size of my pinkie-finger eat?!” Well, it’s actually a very interesting and surprising process!  

                                                                         Wikimedia Commons: Matt Wilson and Jay Clark

When the Carukia barnesi is in the polyp phase, it gathers nutrition via filter feeding. Then, once in the medusa phase it is able to hunt for its prey using multiple pairs of eyes that can detect light. A young Irukandji jellyfish will hunt for small invertebrates such as zooplankton and small crustaceans (Hays 2009) such as the ones displayed in the photograph to the left. Then, when matured, the Irukandji can consume small vertebrate fish as well (Ruzi and Patel 2012). To capture its food, the jellyfish stings its prey using nematocysts that shoot paralyzing venom into the prey’s blood stream. Then, utilizing the tentacles, the prey is brought up to the mouth. From the mouth, the food enters the gastric cavity, or coelenteron, where it begins to be digested, often alive. Cnidarians use extracellular digestion to break down their food. This means that food is broken down before it is absorbed to be used for nutrition. After this, the broken down prey molecules can be absorbed into the radial canal, which then transports the nutrients throughout the bell. Any waste is then excreted out the anus, which is also the mouth. Below is a diagram showing the process of digestion.  



Diagram made by Kelsey Lyons



On this nutrition page you have learned about what C. barnesi eats and how it digests and receive nutrients from its food, but wait a second. Does this organism go on unchallenged? Or is this predator someone else's prey? Curious? Check out the interactions page to learn more!



                                 Next stop: Reproduction



Last Updated: April 26, 2013

Wikimedia Commons: Peter Southwood     Wikimedia Commons: GondwanaGirl    Wikimedia Commons: Zaneta Nemcokova