The "Why Are Starfish Shaped Like Stars?" Story

It was an ordinary day.  Cleaning the glass top of my coffee table in the living room of our beach house.  Years ago I tried to explain that we don't live at the beach, but that our home looks very similar to houses found along a coastal area with a modern flair to it and a wooden walkway, much like a boardwalk, around the house.  Anyway, the coffee table was smudged from our cats walking on it all the time so I thought I would clean it.  I built the coffee table over 20 years ago when we moved into the house and made it so we could display the many sea shells and beach items we have collected over our lifetime during trips to the Jersey Shore and Caribbean islands.  As I was wiping the glass on the coffee table, I looked at the large array of starfish that we have found and placed in our collection.  All of them have five arms except for one that has 23 arms.  Made me wonder why they are called a fish in the first place.  So, I checked out one of my Smithsonian magazines and found a story titled "Why are starfish shaped like stars?"  Seems that scientists can't pinpoint exactly why starfish evolved to have radial symmetry, with arms-usually five, but as many as 40 in some species-growing from a central axis.  There are about 1,500 species of starfish that live in the seabeds around the world.  They are found from the intertidal zone, where the ocean meets land, down to abyssal depths of 20,000 feet below the surface.  Starfish are marine invertebrates which mean they do not possess nor develop a backbone or spine.  And, since they don't possess a backbone, they are not technically fish.  But, they certainly are pretty neat.  At the tip of each arm is an eye that can detect changes in light intensity, and on the bottom are tube feet that enable it to move in any direction.  Several species can regenerate an arm lost to a predator or an accident, and a few can even regenerate a new central disc from a severed arm, as long as a fragment of the disc remains with the arm.

The Royal Starfish

 During a vacation years ago to Sanibel, Florida, I purchased a booklet on collectible Florida shells and found starfish listed in it.  It showed the varieties I should probably find around Sanibel as well as showing one named the Sunburst Starfish which is found in Mexico.  It also points out a starfish that is called the Thin Starfish that is also known as a nine-arm starfish and is famous for its ability to drop and later regenerate an arm.  

The Necklace Starfish

It grows to be between 3 to 12 inches.  I did find several very unusual starfish with names such as the Royal Starfish that is purple and orange in color and is found on the east coast of North America, the Bat Sea Star that is found along the west coast of North America and is orange and red in color, the Crown-of-Thorns starfish that has venomous spines and is found in the Pacific Ocean as well as the Red Sea and Indian Ocean and the Necklace starfish that is jewel-like and found in the Indian Ocean.  All these make my collection seem tame.  Check out some of the starfish that I have been able to find over the years during our travels.  It was another extraordinary day in the life of an ordinary guy.

 A variety of starfish my wife and I have collected from our travels.

A few more starfish from our collection.

The 23 arm starfish.