The Sea Slug - Strange but Real

by Wayne Spencer


    The pictures above are one particular variety of sea slug.  These pictures were adapted from the August 1989 issue of Smithsonian magazine.  This is one of my favorite examples of intelligent design among ocean creatures.  Sea slugs are considered to be mollusks; they live in essentially all the world’s oceans, from polar regions to tropical areas.  The best-known type of sea slugs are known as the nudibranchs.  They get oxygen using something similar to gills except its like their gills are sort of “inside-out,” since the branchial structures that absorb oxygen are outside its body instead of inside like in a fish.  Sea slugs are somewhat like a snail except that they do not have a shell, except for a short time as larvae.  

    Sea slug larvae metamorphose from something similar to a snail to a non-shelled form.  Sea slugs are also hermaphrodites, which means each of them have both male and female sex organs.  Sea slugs are generally very colorful.  They may be white, yellow, purple, or red.  Their color is often determined by what they eat.  They have tentacle or finger like structures (called cerata) that can practically cover their whole body.  The cerata can regenerate if a fish or something bites one off.  At the end of the cerata are special stingers called nematocysts.  So if you ever see one, you don’t want to grab it.  Many Sea slugs also secrete some sort of acid or other toxic chemicals that drives off many fish.  Sea slugs look very strange as they undulate through the water.  For some of them it is hard to tell which end is the head.  Some of them have excellent camouflage and can hide on coral for instance.  They cover a wide range of sizes also.  The smallest can move between grains of sand and the largest, called the black sea hare, is over three feet long.   

    One group of sea slugs have an amazing means of protection.  The aeolid nudibranch sea slugs eat sea anemones.  Sea Anemones live on the bottom and have tentacles with stingers on them and the anemone can catch and kill fish that swim by.  When an aeolid sea slug eats a sea anemone, its digestive system neutralizes the mature functioning stingers so it isn’t hurt.  But the immature stingers that do not yet function in the anemone are eaten and then moved out to the ends of the cerata in the body of the sea slug.  Then the stingers from the anemone actually function in the sea slug!  How amazing, that the sea slug can use the nematocysts from another organism!

    These creatures highlight God’s creativity.  From the point of view of evolutionists, they are accidents of evolution.  But God creates everything with a purpose.  Some sea slugs have been very useful in neurological research because they have very large nerve cells that are easy to study.  They also are important in marine ecosystems.  When God made sea slugs, he was thinking way “outside the box,” or maybe I should say “outside the shell.”