Starfish is an iconic sea animal, that is very popular for its star – shape, which kinda gave it its name.
Let’s find out more about it!
- Starfish is also named as a sea star.
- Starfish is not… fish!
- Starfish are star-shaped echinoderms.
- They belong to the class Asteroidea.
- Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars.
- Starfish are also known as Asteroids due to being in the class Asteroidea.
- About 1,500 species of starfish occur on the seabed in all the world’s oceans.
- You can find them from the tropics to frigid polar waters. T
- hey are found from the intertidal zone down to abyssal depths, 6,000 m (20,000 ft) below the surface.
- Starfish are marine invertebrates.
- They typically have a central disc and usually five arms, though some species have a larger number of arms.
- Many species are brightly coloured in various shades of red or orange, while others are blue, grey or brown.
- Starfish have tube feet operated by a hydraulic system and a mouth at the centre of the oral or lower surface.
- They are opportunistic feeders, and something you don’t usually expect of them is that they are mostly predators on benthic invertebrates.
- Several species have specialized feeding behaviours including eversion of their stomachs and suspension feeding.
- They have complex life cycles and can reproduce both sexually and asexually.
- Most can regenerate damaged parts or lost arms and they can shed arms as a means of defense.
- Starfish have become widely known as examples of the keystone species concept in ecology.
- The tropical crown-of-thorns starfish (Acanthaster planci) is a voracious predator of coral throughout the Indo-Pacific region, and the northern Pacific sea star is considered to be one of the world’s 100 worst invasive species.
- The fossil record for starfish is ancient, dating back to the Ordovician around 450 million years ago.
- Only the ossicles and spines of the animal are likely to be preserved, making remains hard to locate.
- With their appealing symmetrical shape, starfish have played a part in literature, legend, design and popular culture. They are sometimes collected as curios, used in design or as logos,
- In some cultures, despite possible toxicity, they are eaten.
- They have no brain.
- They do have eyes though.
- Sea stars have an eye spot at the end of each arm. This means that a five-armed sea star has five eyes, while the 40-armed sun star has 40 eyes.
- Each sea star eye is very simple and looks like a red spot. It doesn’t see much detail but it can sense light and dark, which is just enough for the environments the animals live in.
- Also, they have no blood. Instead of blood, sea stars have a circulatory system made up primarily of seawater.
- Starfish use filtered sea water to pump nutrients through their nervous system.
- They can live up to 35 years.
- They are unable to survive in fresh water.
- They can have up to 40 arms!
- Sea stars have a tough covering on their upper side, which is made up of plates of calcium carbonate with tiny spines on their surface.
- A sea star’s spines are used for protection from predators.
- Their predators can be birds, fish, and sea otters.
- At least for something of their small size, sea stars can weigh up to 11 pounds.
- Starfish are equipped with hundreds of tiny little feet at the end of each arm.
- The Cushion Starfish has a round blob-like shape, while having all the genetic qualities needed to be a starfish.
- This starfish is actually much gentler than other starfish, feeding on detritus and plants. Other starfish will tend to feed on clams or oysters.
- The scientific name Asteroidea was given to starfish by the French zoologist de Blainville in 1830, and it has a Greek origin.
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