Sea Urchin
Diadema antillarum
A spiky reef gardener with five self-sharpening teeth.
Long-spined Sea Urchins emerge after dark to graze algae from Caribbean reefs. Their extra-long movable spines protect the urchin and can shelter tiny fishes between them.
Find this SeaPal in the card gallery
From field guide to game table
Bring this Sea Urchin home
See which ready-to-play decks feature this SeaPal. Try one in the simulator before you buy, or explore each full deck list.
- 2 copies
Ready-to-play deck
Murky Water Deck
Includes 2 cards featuring Sea Urchin.
Quick dive
Creature passport
- Home
- Western Atlantic and Caribbean coral and rocky reefs, ledges, and crevices.
- Favorite foods
- Mostly reef algae, with occasional tiny animals or drifting food.
- Size check
- Body up to 4 in (10 cm); spines can reach 12 in (30 cm)
Tell-your-friends facts
Four wonderfully wild things
- 1
The hard round inner shell is called a test.
- 2
Its jaw apparatus is nicknamed Aristotle's lantern.
- 3
Hundreds of tube feet work like tiny hydraulic suction cups.
- 4
It senses passing shadows and points its spines toward possible danger.
Ocean superpower
Built to be amazing
Five hard teeth scrape algae and help keep space open for corals.
Junior scientist tip
What should I look for?
Look into reef cracks for a black center surrounded by needle-long spines.
Grown-up research links
We used trusted science organizations to check this profile.