Fascinating facts about Starfish

Stef Zisovska
A starfish from the Pacific - Author: Stef Zisovska
A starfish from the Pacific - Author: Stef Zisovska

Starfish or sea stars are awe-inspiring sea animals that can be seen on underwater rocks and coral reefs or washed out on the seashores around the world. Starfish come in different colors, sizes, and even shapes, but they still have one thing in common – they are all gorgeous. People like to collect them from the beaches worldwide and bring them home as souvenirs. Every time you see a starfish in the sand, check if it’s still alive and if its tentacles are moving. If so, take it back to the water, if it’s dead, then you can take it as a memory from your vacation.

Here are some fascinating facts about starfish that you will be glad to know.

Starfish are not fish at all

Starfish on the beach
Starfish on the beach

We are used to seeing the sea star around water, although it’s not a fish at all. The starfish don’t have gills, scales, and fins like the real fish do which indicates they don’t belong to any fish species. They even have a different way of moving through the water. The fish move with the help of their tails while the starfish move with the small tube-shaped feet.

Sea Stars Are Echinoderms

Sea star
Sea star

Echinoderms mean that the starfish belongs to the same group of animals as the sand dollar, the sea cucumber, and the sea lillie. The phylum od Echinodermata to whom the sea star belongs has more than 6000 different species. Echinoderms display a radial symmetry which means their body parts are placed around a central core. Most of the starfish have 5-point radial symmetry because they have five body parts. These animals don’t have a right side or left side, but what they have is a bottom or top side.

There are a couple of thousands sea star species in world’s seas

There are more than 2.000 starfish species in the planet’s waters. Some of them live in deep waters and other close to the shore. And if you thought that they can only be found in tropical waters, that’s not true because sea stars also live in cold waters and even can be seen in the polar regions.

Sea stars can regenerate arms

Colorful starfish
Colorful starfish

These wonderful creatures can regenerate their lost arms, though this process may take up to a year. When they get attacked by a predator, they don’t fight. Instead, they take off the arm, escape and grow a new one. Isn’s that amazing? Some sea star species can even regenerate a whole new sea star out of the ripped off arm.

Sea stars don’t have blood

Another fascinating fact about sea stars is that they have a salt water in their system instead of a blood. On the top of every starfish, there is a light-colored spot called madreporite from where all the water enters into the sea star’s water vascular system. From there, the sea water is transported to the tube feet that help the arms to extend.

Starfish eat with their stomach inside-out

A Circeaster pullus starfish everting its stomach to feed on coral – Author: NOAA – CC BY-SA 2.0
A Circeaster pullus starfish everting its stomach to feed on coral – Author: NOAA – CC BY-SA 2.0

Are you ready to read about the most incredible feeding way in the world? Sea stars have a unique way of catching the pray and then eating it. A sea star feed on barnacles, mussels, snails, and small fish. Knowing that its tiny mouth it’s on the underside of the body, this cute animals wraps its arms around the prey and it kind of hugs it. But, the things are not optimistic at all. Then, the starfish pushes its stomach through its mouth, digests the animal and slides its stomach back into its own body. Although this way of alimentation seems like a part of a low-budget horror-Sci-Fi movie, the sea stars are awesome and we love them.

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stef-zisovska

stef-zisovska is one of the authors writing for Outdoor Revival