Starfish or sea stars are star-shaped echinoderms that belong to the class Asteroidea. Common usage regularly finds these names being applied to ophiuroids that are properly referred to as brittle stars or ‘basket stars.’ Almost 1,500 species of starfish are found on the seabed in all the oceans of the world, from tropics to the frigid polar waters. They can survive in the intertidal zone down to abyssal depths, 6,000 meters (20,000 ft.) below the surface.
The fossil record for the starfish is ancient, dating back to the Ordovician about 450 million years ago, but it’s rather poor, as starfish seem to disintegrate after death. Only the spines and ossicles of the animal are certainly to be preserved, making the remains difficult to locate. With their attractive symmetrical shape, starfish have played a role in legend, literature, design and famous culture. They are at times collected as curios, used as logos or in design, and in some cultures, regardless of possible toxicity, they are eaten.
This marine creature has always generated high interest owing to its radial symmetry with five or more arms. Starfish belongs to a vast group of marine animals known as echinoderms. They can be found in almost all oceans of the world. Significant populations of starfish usually live in the Pacific and Indian oceans. Starfish (also referred to as sea stars) are mostly found in common swallow waters. There are more than 2000 species of starfish, and not even a single one can survive in freshwater.
Familiar yet undeniably alien, the starfish are bizarre creatures which inhabit a broad range of ocean environments. Their appearance regularly matches the common depiction of their celestial namesake, though those freaky bodies hold adequate of surprises. So, what creature could have no brain but have eyes on its feet, or lacks blood but can digest outside of its body? Get ready to learn more about creatures which usually seem to disobey the laws of animal biology.
Mind-Bending Facts about Starfish:
- They have no blood, and no brain-starfish only use filtered sea water (not fresh) to pump nutrients through their nervous system.
- They have several birthdays! It has an average lifespan of 35 years.
- They can be very heavy- at least for something concerning their small size, starfish can weigh up to eleven pounds.
- A starfish is not a fish- they are related to sea urchins and sand dollars.
- There are about 2,000 species of starfish-they live in both cold and warm climates around the world.
- They often have 5 arms-There is a group of less common species which have more than five!
- They can’t survive in freshwater- salty water all the time!
- They eat inside out –when they capture their prey, they have small suction cups to hold their food. Therefore, their stomach exits their mouth to digest only the food and reenters the body when they finish eating. Sounds like a horror series/movie right? Close, but they seem more majestic than creepy.
- Starfish aren’t hermaphrodites (animals that have characteristics of both genders), but they can change their gender whenever they like during their lifetime.
- Starfish mouth is situated on the lower side of its body. The anus is situated on the upper side of the body.