What You Didn't Know About Starfish

Starfish, also commonly known as sea stars, are among the most visibly recognized sea creatures, but did you know that a starfish is not actually a fish? Here are more interesting facts about starfish.

  • There are more than 2,000 different species of starfish.
  • Starfish lack some of the main defining features that fish possess such as gills, fins, and scales. Starfish are most closely related to sand dollars, sea cucumbers, and sea urchins, which are all part of the Phylum Echinoderm.
  • Because starfish do not have fins, they move themselves through the water by utilizing theirtube feet, which are located on the underside of the starfish. These tube feet also help starfish to hold onto their prey once it has been caught.
  • Starfish do not have blood in their bodies. Instead, they have a water vascular system that pumps seawater through the tube feet and throughout the body.
  • If a predator attacks a starfish, it is common for the starfish to forfeit one of its arms in order to survive the attack. This is beneficial to a starfish because it can actually regenerate a new limb! Although this is a helpful defense, the process of regeneration is slow; it takes about a year for a new arm to grow back.
  • A starfish’s stomach is located on its underbelly. When it catches its prey, usually a mussel or clam, it wraps itself around the animal and uses its tube feet to pry the shell apart. Then, the starfish’s stomach actually comes out of its mouth and into the prey’s shell to eat the meal! After eating, the stomach goes back inside the starfish’s body. This allows the starfish to eat prey that its tiny mouth wouldn’t typically be able to fit around.

Article written by Sarah Wyland

Sarah Wyland
Sarah never gets in trouble for being on Facebook and Instagram at work, because its her job. As social media manager, she gets to tell the stories of travelers, teachers, and interesting places. Other titles she enjoys include dog mom to Knox, barre instructor, Crossfit athlete, avid reader, and world traveler.
Category: Science