Starfish - Sea Star, Armed Sea Critter
The starfish is incorrectly named. The starfish simply isn’t a fish and for centuries marine biologists and scientists have been trying to get it renamed the “sea star” as it is. In fact, the starfish is an echinoderm. The echinoderm group also includes closely related species like the sand dollars, sea urchins and sea cucumber.
There are believed to be over 2000 species of starfish living in our oceans. They can be found in the warmest tropical waters as well as the cold seabed. The most common variety has five arms but amazingly you will find some with in excess of forty arms!
They have bony calcium-rich skin which keeps them protected from many predators. Many also come in a range of striking colors which warn off potential predators.
There are no freshwater starfish as they are all found in salty marine waters.
As well as being known for their characteristic shape, they are known for their ability to regenerate their limbs and some can even regenerate their whole bodies. They manage this by keeping their internal organs in their arms which means many can regenerate a whole new body from just one severed arm, although many species do need the central body to be able to regenerate their limbs.
Another fantastic and intriguing feature about the starfish is its ability to consume its prey from outside its body. Using small suction-cupped feet which cover its entire body, they can force open oysters and clams. Then, their sack-like stomach emerges (similar to a tongue) and spills inside the oyster or clam shell. The stomach then envelopes, absorbs and digests the pray, and then withdraws back inside the body.
Some species are considered edible delicacies whereas other should not be considered as part of anyone’s diet! There are over 2000 species but some of the most common include: the carpet sea star, Japanese sea star, bat sea star and horned sea star.
The star fish is at extreme risk of any water pollution as they have no way of filtering the toxins from the water when it becomes polluted. Oil spills in particular are a great threat to the them.