Ocean Life: Starfish (Sea star)
Starfish (asteroidea), which are now named sea stars, are closely related to sea urchins and sand dollars. There are about 2,000 living species worldwide. Their bony, calcified skin protects them from most predators and their striking bright colors camouflage them and warn off potential predators as well. According to National Geographic, sea stars can weigh up to 11 pounds and live a life span of up to 35 years.
Where They Live:
Starfish live in all of the world’s oceans, including tropical habitats and the cold seafloor. They are purely marine animals; none can be found in freshwater.
Sea stars are carnivores; they use their tubed, suction-cupped arms to pry open clams and oysters. Their sack-like stomach emerges from their mouth and slides into the shell to surround the prey and digest it.
How They Mate:
They can reproduce sexually, by spawning, or asexually. Asexual reproduction does not allow genetic diversity as it is usually the result of dismemberment, which then results in two starfish with the same DNA. When they reproduce sexually by spawning, the sex cells are released into the water and become fertilized. They then become eggs.
Did you know that starfish actually use filtered sea water instead of blood to pump nutrients through their bodies?!
What Do You Think?
How many arms can a sea star have?
Answer: With about 2,000 living species, you can imagine the large variety there is of sea stars. With that in mind, even though the five-arm varieties are the most common, sea stars can be found with up to 20, even 40 arms!
To learn more about ocean life, click on the links below!