Coral — Animals, Not Rocks!
Here is a surprise: coral is NOT a rock or a plant. Coral is actually made up of tiny animals called polyps! Each polyp is about the size of a pencil eraser and looks like a tiny upside-down jellyfish.
Coral polyps have soft, tube-shaped bodies with a mouth surrounded by tentacles. At night, they extend their tentacles to catch tiny floating organisms called plankton. During the day, they pull their tentacles back inside for protection.
Here is the key to reef building: each polyp creates a hard limestone cup around its base, like building its own tiny stone house. As polyps reproduce and new ones grow on top of old ones, these limestone cups stack up over hundreds and thousands of years, forming the massive structures we call coral reefs.
The Great Barrier Reef in Australia is the largest coral reef system in the world — it stretches over 1,400 miles and is so big it can be seen from space!
**Wow Factor:** Coral reefs have been growing on Earth for over 240 million years — even before the dinosaurs!