Elkhorn Coral: a two-minute wildlife lesson

At the Seaside · day 7 of 7

Five facts

1. Elkhorn coral lives for centuries, yet reaches full size in just 10-12 years.
2. Elkhorn coral can tower over 2 meters and spread 13 meters wide, forming antler-like lattices.
3. Storms snap off branches that can settle elsewhere and grow into new colonies, genetic copies of the parent.
4. It lives in sunny shallows 1-5 m deep, where the tiny algae living in its tissues get plenty of light.
5. When murky water blocks light, it can switch to night-time filter feeding, snatching zooplankton with its tentacles.

The quiz

1. How long does elkhorn coral take to reach full size?

• 1-2 years
• 3-4 years
• 10-12 years (correct)
• 50 years

It reaches full size in just 10-12 years.

2. How wide can an elkhorn coral spread?

• 13 meters (correct)
• 3 meters
• 5 meters
• 30 meters

It can spread 13 meters wide.

3. How does a broken branch become a new colony?

• It floats to the surface
• It settles elsewhere and grows (correct)
• It turns into sand
• It turns into seaweed

Broken pieces can settle elsewhere and grow into new colonies.

4. How deep does elkhorn coral live?

• 20-30 m
• 40-50 m
• 100 m
• 1-5 m (correct)

It thrives in shallow water 1-5 m deep.

5. What does elkhorn coral catch when light is blocked?

• Zooplankton (correct)
• Seaweed
• Large fish
• Sand crabs

It snatches zooplankton with its tentacles at night.

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