There are about two thousands kinds of sea stars living in oceans world wide, from tropical seas to very cold sea floors.
The kind we see most often is the five armed type, however there are some that will have as many as forty arms.
What we call a star fish, isn’t actually a fish at all and because of this
“Marine scientists have undertaken the difficult task of replacing the beloved starfish’s common name with sea star because, well, the starfish is not a fish. It’s an echinoderm, closely related to sea urchins and sand dollars.”
The picture above could be one of many different things depending on what you believe. Is it a reticulated sea star, a reticulated starfish, a cushion star or even a Bahama starfish? You decide.
Sea stars have bony skin, that keeps them safe from most of the predators who might eat them and many of them wear bright or bold colors that will scare away attackers.
They are only marine sea stars, with no freshwater ones anywhere in the world.
Sea stars are very famous for being able to regenerate their arms, and in some cases their entire bodies can be regenerated from just a bit of an arm left.
This can happen because they have most of their vital organs only in their arms.
Some require the middle body to be in place to regenerate, but a few species can grow an entirely new sea star just from a portion of a severed limb.
Most sea stars also have the incredible means to eat outside their own bodies. They do this by putting their stomach outside the body.
Using tiny, suction-cupped tube feet, they pry open clams or oysters, and their stomach emerges from their mouth and oozes inside the shell. The stomach then envelops the prey to digest it, and finally withdraws back into the body of the sea star.
Starfishes (Sea Stars) - Asteroidea - Seesterne
The sea star is really a kind of animal known as an “echinoderm.” An echinoderm essentially means that this kind of sea animal has spiny skin.
Starfish can’t swim at all, but they do crawl and climb.
Most are about 8 inches or so across their middle but some are as large as a small automobile in size.
Their arms bend every way, and have tiny little spines on them that help the starfish stick to rocks as it crawls in search of prey.
Starfish are fairly strong animals and are hardy against most enemies. They have a spiny skin that isn’t very appealing to other fish and generally they aren’t eaten.
They mate by standing upright on the sea floor, the males release their sperm, while the female releases eggs into the ocean.
Very often you will see them climb up to the top of a tall rock to be able to get the highest and release theirs. They are fertilized and begin to grow outside of both mother and father.
Starfish breathe through their feet and have little tiny breathing tubes all over their bodies. They also have no eyes, but have instead a small eyespot on the end of their arms, so they can tell if it is light or dark, but generally they can’t see shapes it is believed.