🐾 Starfish

Starfish

▶

Tap a video to play it

🔍 See more videos →

Photos

✖ ❮ ❯

Who it is

• Scientific name: Class Asteroidea
• Family & relatives: Sea stars are echinoderms, related to sea urchins, sand dollars, and sea cucumbers.
• How to spot it: A star-shaped body, usually with five arms, and a bumpy skin over the top.

Its body & abilities

• Size: Most span about 15 to 25 centimeters, though some giants grow much larger.
• Weight: Most are light, typically well under a kilogram for common species.
• Body & adaptations: They have no brain or blood and move using a water-powered system of tiny tube feet.
• Top speed: They creep very slowly across the seabed on hundreds of tiny tube feet.
• Strength: Their amazing power is regrowing lost arms, and some can regrow a whole body from one arm.
• Senses: They have a simple eyespot at the tip of each arm that senses light and shadow.
• Growing up: They begin life as tiny swimming larvae that drift before settling and turning into little stars.

Where it lives

• Habitat: They live on the sea floor from tide pools and rocky shores to the deep ocean.
• Where in the world: Sea stars are found in every ocean, from the tropics to polar seas.
• Territory: They wander in search of food rather than defending a territory.

What it eats

• Diet: Many are predators, while others scavenge or feed on tiny drifting particles.
• Favorite foods: They eat clams, mussels, oysters, snails, and other slow-moving prey.
• How it hunts: They pry open a shell with their arms, then push their stomach outside the body to digest the prey.

How it behaves

• How it moves: They glide along using rows of tiny tube feet on the underside of each arm.
• When it is active: Many feed slowly through the day and night, tracking prey by scent.
• Family life: They are mostly solitary but can gather in large numbers where food is plentiful.
• How it talks: They rely on chemical cues in the water rather than sights or sounds.
• Babies: Most release eggs and sperm into the water, and some can also split to form new stars.

Its place in nature

• Role in nature: As key predators they shape whole communities by controlling mussel and shellfish beds.
• Conservation: Some species have suffered from a wasting disease, while others remain common.
• Dangers: Fish, seabirds, sea otters, and other sea stars prey on them.

Life & legacy

• How long it lives: Many live around 5 to 10 years, with some species living much longer.
• In our culture: The five-armed star is a classic symbol of the seashore in art and decoration.
• Where to see it: You can find them in tide pools at low tide and in touch tanks at aquariums.
• Fun fact: A sea star can push its stomach out through its mouth to digest food outside its body!