12 Cool Facts About the Great Barrier Reef

1. It is GREAT. The Great Barrier Reef stretches 2 300km from the Torres Strait to just north of Bundaberg. It covers an area of 345 000km2 and is comprised of nearly three thousand reefs and more than nine hundred islands and cays.

The Reef is 344,400 km2  and The United Kingdom is 242,495 km². The Great Barrier Reef is so extensive because a mountain Range as big as the Andes slowly eroded away and formed a huge shallow area off the coast (The Great Dividing Range is what is left of this enormous range). Its oldest living creature may be the Barrel Sponge, a big one probably started growing when the Vikings were raiding English monasteries.

2. World’s Largest Living Structure. It is the world’s largest living structure, and it is the biggest coral reef system on the planet. Only the tropical rainforests rival the reef’s biodiversity and richness of species.

3. A Wonder of the World. The Great Barrier Reef was named a UNESCO World Heritage site in 1981 and is considered by many to be one of the Wonders of the World.

4. Many Creatures. The Great Barrier Reef needs sunlight to flourish, so snorkelers will see a mosaic of life just below the surface. The reef boasts:

  • 350 types of hard coral and a third of all the world’s soft corals;
  • 5,000 to 8,000 molluscs and thousands of different sponges, worms, crustaceans, and other less familiar creatures;
  • about 800 species of echinoderms (starfish, sea urchins);
  • 1,500 species of fishes;
  • 22 species of seabirds that live and breed on the islands within the marine park;
  • more than 30 species of marine mammal; and
  • 6 species of marine turtles, all listed as threatened

5. Newly Discovered Animals!  As recently as September 2008, scientists from the Australian Institute of Marine Science reported they had discovered hundreds of previously unknown animals. New discoveries include a shrimp-like creature with a hugely disproportionate claw, a tentacle-free jelly fish that emits a bioluminescent light, and a tiny sea weed that hasn’t been seen for over 200 years until now.

6. It is Threatened. The three main threats to the Great Barrier Reef include over-fishing, land-based pollution and global warming. Agricultural activities including sugar cane farming and cattle grazing, increasing industrial and urban coastal development, increased tourism activity and the loss of natural filtering systems of wetlands and mangroves have all led to an increase in sediment and chemical residues entering the waters of the GBR. These issues are further compounded by inadequate environmental planning regulations for the coastal areas of Queensland.

7. It is Old. Back when Woolly Mammoths and cavemen were walking around Europe (about 12,000 years ago), you could walk to where the reef is now.

8. It Has Had Many Lives. The first Great Barrier Reef started about 600,000 years ago but dried up and regrew dozens of times (every time there was an ice age).

9. It is Made Up of Fascinating Corals. Corals have plants (or algae) in their skin, in the cells of their skin. This algae get energy from the sun and gives it to the coral. The coral get more than 90% of the energy they need from this algae (This is like you eating your vegies and then turning green and living off sunshine and an apple a day).

  • Corals are really very small upside-down jellyfish (the smallest is 1mm the largest is 15cm). At that size there would be 10 million per square kilometre, or 3.444 trillion on the Great Barrier Reef (or if the average polyp is a word then about 49 million books)
  • When ready corals grow a brother or sister out of their body (usually between the tentacles) and they stay connected even after their sibling grows their own room.
  • More and more brothers or sisters are made, more rooms are added until eventually houses grow up and form buildings and we call these buildings, coral.
  • Corals need sun so they grow on top of each other, as the sea level rises so does the coral and really deep coral pinnacles may have started growing 1000’s of years ago. SO….when you are at the bottom of one think about The Romans and Gladiators and Aphrodite the Goddess of Love!

10. Night Action! At night a whole bunch of plankton migrate from the depths to feed on the stuff that grew during the day, a whole bunch of reddish or see-through fish with big eyes come out to feed on them (as well as a whole bunch of crabs, snails, worms and sea stars that come out to feed under the cover of darkness), and a whole bunch of sharks, eels and octopus come out to feed on them (and on each other).

11.Most Fish are Ventriloquists…and They Smell Good. They have a muscle that vibrates inside them, which hammers a rib bone into their swim bladder and makes a drum beat. Different rhythms have different meanings (danger, go away, I love you) and so they can talk to each other without moving their mouths.  Fish also smell good. To survive, a fish remembers the smells before it was attacked, or before another fish was attacked or before another fish drummed out a warning call. Old fish are more likely to survive because they have a good smell memory.

12. Wacky Creatures. The most fantasy-world-like swimmer is the feather star (it is like watching a scene from a movie where a magician has made a flower fly, paddling its arms up and down in groups of four). The most alien-looking creatures you can’t see but you can see the fish eating them: plankton that look like commas, fairies, alien spaceships or hairy swimming beans.

We can show you coral, crustaceans and all sorts of creatures at the Great Barrier Reef on some of our cool reef trips:

Ecosystems at Risk: Coral Reefs

Reef & Marine Studies

Ecosystems at Risk: Reefs and Rainforest

On Small World Journeys student tour Ecosystems at Risk, students investigate water quality at the reef, look for signs of coral bleaching, and potentially damaging coral predators such as the Crown of Thorns.  If students want even more educational time at the reef, they can opt for our Reef & Marine Studies excursion.


Thanks to our marine biologist David Witherall for this information!