Seeing a starfish, women generally admire it. Many people think that starfish are very beautiful animals, as romantic as a star falling into the sea.

Even if we haven't been to the beach, we have seen the animation of SpongeBob SquarePants. Among them, SpongeBob's good friend is a pink starfish.

Starfish are quirky little creatures that live on the seashore. They like to cling to rocks, and they can stay on the beach when the tide goes out. Starfish are generally only the size of a palm, and most of them have five horns, like the rays of light emitted by stars in the sky.

Starfish is a huge and diverse creature, with 1,600 extant species and 300 fossil species. Starfish are widely distributed in sandy bottoms, soft mud bottoms, coral reefs and oceans of various depths.

Many tiny crystals are growing on the skin of starfish. These crystals act as the starfish's eyes, similar to perspective mirrors, capturing important information about the surrounding environment. These crystals have excellent light-gathering properties and can acquire images from all directions, comparable to lenses made by humans. Therefore, the offensive strategy of attacking from behind is ineffective against starfish.

Starfish usually have 5 arms, a few species have 4 or 6 arms, and some species even have as many as 40 arms. The undersides of these arms are lined with dense tube feet, which not only help the starfish capture prey but also allow the starfish to climb rocks.

Starfish do not have blood, their circulatory system consists mainly of seawater. Seawater is pumped through the sieve plate into the animal's water vasculature. This is a type of trapdoor called a sieve, and can often be seen as a light-coloured spot on top of the starfish.

Sea water enters the starfish's tube feet, causing the arms to extend. The muscles inside the podia are used to control the contraction of the limb.

We usually think of gentle animals as herbivores and ferocious animals as carnivores. Then, this gentle-looking, well-behaved, and relatively easy-to-approach starfish should be more suitable for eating seaweed or plankton!

But the fact is just the opposite. Starfish are not only carnivores but also fierce carnivores. Starfish often bully the weak, shellfish, crabs, sea anemones, etc. are the targets of their bullying.

During the long evolutionary process, starfish have developed a very effective survival strategy, and their vitality is extremely tenacious. Many animals can eat starfish, but the hard, calcium-carbonate-rich shells and scarce meat of starfish deter predators. Starfish also have a strong ability to regenerate; even if it is torn into several pieces, each piece can grow into a new starfish.

Since starfish have such amazing regenerative abilities, the loss of arms and limbs is a trivial matter for them. Scientists are exploring the mystery of starfish regeneration ability, to draw inspiration from it and seek a new medical method for humans.

Starfish are an indispensable link in the marine food chain. Its predation plays a role in keeping the biota in balance. For example, on the west coast of the United States, there is a kind of thorn starfish that often preys on the sea rainbows that are densely attached to the reefs.

In this way, the excessive reproduction of sea rainbows can be prevented, preventing them from invading the territories of other creatures, thus maintaining the balance of biological groups.