How do many sea stars eat mussels?

Push their stomach out of their mouth

Starfish Quiz: Places, People and Key Facts

A starfish can push its stomach out of its mouth to digest a mussel, and this starfish quiz explores the strange world of sea stars. Learn why they are not fish, how a wasting disease swept Pacific coasts and why crown-of-thorns starfish worry scientists on the Great Barrier Reef.

Start Starfish Quiz

🎯 Daily Trivia Challenge • 🧠 10 Questions • ⏱️ 150 Seconds

Question 1 / 10 Time: 150s

Fish
Are starfish really fish?
Blood
What do sea stars use instead of blood?
Stomach
How do many sea stars eat mussels?
Regrow
What can sea stars regrow?
Eyes
Where are a sea star's eyes?
Feet
How do sea stars move?
Crown
Which sea star eats coral on the Great Barrier Reef?
Wasting
What disease killed millions of sea stars on Pacific coasts after 2013?
Arms
Which sea star can have over 20 arms?
Keystone
Which sea star helped define the idea of keystone species?

Explanations: answer key for all 10 questions

Q1: Are starfish really fish?
Answer: No, they are echinoderms
Scientists prefer the name sea star.
Q2: What do sea stars use instead of blood?
Answer: Seawater
A water vascular system moves it.
Q3: How do many sea stars eat mussels?
Answer: Push their stomach out of their mouth
They digest prey outside their bodies.
Q4: What can sea stars regrow?
Answer: Lost arms
Some can regrow a whole body from one arm.
Q5: Where are a sea star's eyes?
Answer: At the tips of its arms
They detect light and shapes.
Q6: How do sea stars move?
Answer: Hundreds of tiny tube feet
Suction helps them grip rocks.
Q7: Which sea star eats coral on the Great Barrier Reef?
Answer: Crown-of-thorns
Outbreaks can devastate reefs.
Q8: What disease killed millions of sea stars on Pacific coasts after 2013?
Answer: Sea star wasting disease
Sunflower stars were hit hardest.
Q9: Which sea star can have over 20 arms?
Answer: Sunflower sea star
It is one of the largest and fastest.
Q10: Which sea star helped define the idea of keystone species?
Answer: Ochre sea star
Robert Paine studied it in Washington State.

Starfish Quiz – Stars of the Seafloor

Starfish, or sea stars, are echinoderms related to sea urchins and sand dollars, not fish. There are about 2,000 species, living from tide pools to the deep sea, most with five arms but some with 20 or more.

Sea stars have no brain or blood. They move with hundreds of tube feet powered by a water vascular system and have simple eyes at the tips of their arms. Many eat shellfish by prying shells open and pushing their stomachs inside.

Sea stars play key roles in ecosystems. Robert Paine's experiments with ochre sea stars showed how one predator can shape a whole community. Sea star wasting disease and crown-of-thorns outbreaks show how changes in their numbers affect oceans.

What This Quiz Teaches

Ocean fans and students will enjoy these questions.

Why sea stars are not fish
How they eat
How they move
What they can regrow
Why they matter to ecosystems

Did You Know?

Sea stars can live 35 years.
Brittle stars are close relatives.
Some sea stars brood their young.
Sea stars are found in all oceans.
Sunflower star loss led to more urchins.