Cauliflower Coral
Pocillopora verrucosa
It looks like a rock and grows like a plant, but a coral is an animal — thousands of them, living as one.
A coral is covered in polyps: tiny animals related to jellyfish and sea anemones, each sitting in a little cup of stone it builds for itself. Thousands of them live joined together as one colony, and over thousands of years, colonies build reefs. The cauliflower coral is one of the main builders of Cabo Pulmo, the northernmost coral reef in the eastern Pacific, in Baja California Sur.
On the conservation status
Listed as Endangered by the IUCN in 2024, when scientists reassessed the world's reef-building corals and found 44% of them at risk of extinction. The biggest threat is the sea getting warmer.
- Colony
- Up to about 50 cm (20 in) across
- Branches
- 1–2 cm thick, covered in warts
- Colours
- Pink, brown, cream or greenish
- Depth
- Mostly 1–15 m (3–50 ft)
- Food
- Sugar from its algae, plus plankton
- Class
- Anthozoa — the flower animals
The good stuff.
An animal, not a plant
A coral has no leaves or roots. Each polyp has a mouth ringed with stinging tentacles, and at night it pokes them out to catch tiny floating animals, just as its cousins the jellyfish and sea anemones do.
Algae inside
Living inside the coral are huge numbers of tiny algae. They use sunlight to make sugar, share it with the coral, and give it its colour. In cauliflower coral, the algae are already inside the eggs before they're released.
Why corals turn white
When the sea stays too hot for too long, corals push out their algae and turn white. That's called bleaching. A bleached coral is still alive, but it's starving, and if the heat doesn't let up, it dies.
Bodyguards in the branches
Tiny crabs and snapping shrimp live between the branches. In return for a home, they fight off animals that come to eat the coral, like the crown-of-thorns starfish.
The reef that came back
Cabo Pulmo was badly overfished until 1995, when the families who lived there helped get it protected and stopped fishing. By 2009 there was more than five times as much fish on the reef as in 1999, and sharks and big groupers had come back.
Two ways to make new coral
Cauliflower coral can release eggs and sperm into the sea, which grow into new colonies somewhere else. It can also grow a whole new colony from a piece that breaks off.
Wait, really?
- ✦
Its scientific name, verrucosa, means covered in warts.
- ✦
Cabo Pulmo's reef is thought to be about 20,000 years old.
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Coral reefs cover a tiny part of the sea floor, but about a quarter of all the kinds of animals in the ocean live on them.
What it sounds like
Silent. Corals make no sounds — but a healthy reef is noisy, full of crackling shrimp and grunting fish, and young fish and baby corals may follow that noise to find a reef to settle on.
Where you might see one
Cabo Pulmo National Park, on the Gulf of California coast of Baja California Sur. It also grows on reefs across the Indian and Pacific Oceans, from the Red Sea to Hawaii.
The trouble
- Marine heatwaves that cause bleaching
- Seawater turning more acidic, which makes it harder to build a skeleton
- Pollution and mud washing off the land
- Anchors, careless divers and building along the coast
One real thing
On a reef, never touch, kick or stand on coral: even a light touch can hurt the polyps. Keep your fins up and away from it, and choose boats that tie up to mooring buoys instead of dropping anchors.
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