Curious Facts: Do Starfish Have Eyes? Here's How Sea Star Detect Light! | Kidadl


Curious Facts: Do Starfish Have Eyes? Here's How Sea Star Detect Light!

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Starfish are beautiful sea creatures and are popularly known as sea stars.

These aquatic animals have more than 2000 varied species that come in different shapes, sizes, and colors. This sea star with five arms doesn't really show any visible body parts, including eyes.

The starfish has regenerative powers that come in handy in many circumstances. When the sea star loses one of its arms due to an encounter with a predator or during an escape, the regenerative cells in them ensure that they regrow this arm.

Starfish have leather-like, rough, and tough skin. While nobody can see them at first glance, starfish actually have hundreds of very tiny feet that help them move about under the water. A fascinating and unique feature of starfish is also their ability to eat as well as digest food outside their bodies.

Due to the high number of different species of starfish available, it will be wrong to assume they all look the same. Although still called 'star' fish, not all of the species and subspecies of starfish are actually shaped like stars. Like what you have read so far? Keep going for more!

If you really like this article, you might also enjoy our other articles such as starfish facts and do stick bugs bite here on Kidadl!

How do starfish see?

A starfish has neither a brain nor blood in its body. They don't even have a central nervous system.

However, they do have a stomach, mouth, and eyespots. These eyespots act as eyes and are made up of several light-detecting cells. These cells aren't covered with a lens like those that cover human or other animal eyes. This limits what and how a starfish sees the world around it.

While humans and most animals can see the world around them in vivid colors and defined tones, starfish do not have this privilege. Starfish eyes can be known as compound eyes that can only see in terms of light and dark.

Recently, scientists have found out that the eyespots of sea stars can also notice large structures around them. However, they cannot catch on to an object that moves too fast as the cells work slow.

How many eyes do starfish have?

An interesting fact about sea stars is that these animals' eyes or eyespots aren't situated in the center. Many cartoons portray a starfish with a mouth and eyes in the center of its body. However, this is not true.

The eyespots on a starfish are located on each of its arms. Each eyespot of a starfish is a bundle of light collecting units situated in one of the hundreds of tiny tube-like feet on each arm. A tube foot is how the sea star is able to move and swim in the ocean. There are hundreds of these in each arm of the starfish. When water is filled up in the starfish's arms with the help of these tube-like feet, the arms act as legs and the fish moves.

People can see the eyespot when they hold a starfish in their hands. At the little upturned corner of each arm, there is a red dot. This red dot is the eyespot. A five-arm starfish will have five eyespots, and the more arms a starfish has, the more eyespots it will have too.

Due to the high number of different species of starfish available

How do starfish detect light changes?

The eyespots of starfish are photosensitive, which helps them to detect things around them. The compound eye of a sea star has multiple lenses, which are known as ommatidia. These lenses make a single pixel of the complete picture that an animal sees.

Some scientists have found that the deep-sea starfish, a species of sea star that stays so deep in the water where even the sunlight can't penetrate, can still see despite the extreme darkness around it. It is considered by some that these starfish can see clearer than tropical starfish that live in shallower waters.

Some further studies show a few of these species are also bioluminescent. This means that they create short light flashes that make their skin glow. It not only helps these deep-sea creatures to see clearly but these flashes are also considered to be glowing signals for potential mates to approach.

Starfish vision is different from human vision. They do not see colors as humans do. The eyes of a starfish work in a very basic manner, where they can just sense enough to distinguish between light and dark. Their eyes cannot catch fast-moving objects as they are not developed in the same manner as that of humans. Due to the unique placement of their eyespots, starfish have almost a 360° vision field. This is possible when none of its eyespots is blocked.

The eyespots of this species help them to navigate the ocean and see coral reef and other objects around them. The sight of this organism might not be as developed as that of humans, but it does assist them to see somewhat in the dark ocean and survive.

Do starfish have eyes on their legs?

Even though starfish may seem immobile and stationary in nature, they do move about in the ocean in pursuit of food and to escape other predators. The arms of a starfish also act as legs to keep them mobile.

The body of a starfish is made in a unique way. It is an organism that has no brain or blood but can still live and eat and perform other bodily functions such as digesting. The skin on the underside of each arm has thousands of tiny tube feet, which, when filled with ocean water, make the arm move.

These feet also produce a glue-like substance that is secreted when they want to stay put at a place such as a coral reef. The eyespots of a starfish are situated at one of these tube feet under the skin. They are located at the edge of each arm and appear as a blackish or reddish dot that is visible when looked upon closely.

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for Curious facts: do starfish have eyes? Here's how sea stars detect light then why not take a look at Do fish have lungs? Complete respiration in fish explained or Narcissus flower meaning and symbol facts explained!

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