Corals are weird creatures – If you touched most coral (which we don’t recommend, by the way), it feels like a rough, sometimes slimy, rock. That’s because the hard part of coral is actually an excreted skeleton made up of calcium carbonate (the same stuff your bones are made of). But if you looked at the rock with a magnifying glass, you’d see what looks like a garden of tiny flowers – these “flowers” are the individual animal polyps which are basically mouths connected to stomachs surrounded by arms. If you had a microscope, you could see that within the cells of most polyps, there is a living plant. So, though scientists classify corals as animals, most coral animals in Hawaii have to have plants and rock to survive!
So if the coral animal is stuck in one place all day, how does it find food?
Ahh…that’s where the plant living inside the coral cells becomes important. The plant, called zooxanthellae (zoe-zan-THEL-ay) is actually a little power plant for the coral. It gets energy from the sun (photosynthesizes) and the sugar it makes as a by-product help feed the corals. At night, the coral animal snacks on plankton by extending its arms and entrapping the floating buffet as it drifts by.
Why don’t you recommend touching coral? Will it sting me?
The coral animal is a delicate little creature. Touching it, even gently, can damage the polyp. And while there are some stinging corals in the world, the one most people have heard about called “Fire Coral” doesn’t live in our waters. Still, coral can host other stinging animals which are no fun to encounter. Besides, as soft as your skin gets when you’re playing in the ocean, accidently brushing up against a stony coral can result in a nasty scrape!
How many different types of coral are there?
There are thousands of coral species in the world – only about 150 species live in Hawaii, but unless you were looking through a microscope, it would be difficult to tell many of these apart.
Why are corals so beautifully colored?
Oddly, it’s not the coral animal or the skeleton that give the majority of corals in Hawaii their color – it’s the algae inside the cells! Some researchers believe the colorful algae also acts as a kind of sunscreen for the corals, filtering out harmful UV rays.
Besides looking beautiful, why is coral important?
Coral is important for lots of reasons. The stony reef provides protection to the coastline from waves and storm surges. The reef also provides shelter for lots of marine fishes and invertebrates, and the polyps (and the slime they produce) are food sources for many as well. Humans use all sorts of products derived directly from coral including the skeletons of some corals for human bone grafts, and the bioactive substances in others for pharmaceuticals used to treat cancer and other debilitating diseases.
What’s the best way for me to see coral?
Visitors and residents of Hawaii are very lucky because coral reefs grow right up along the shorelines of many of our beaches. Snorkeling and scuba diving are excellent ways to explore the reef, but if you don’t want to get wet, we highly recommend a cruise aboard our Glass Bottom Boat. Regardless of where you enter the ocean, it’s important to first get advice from local experts. While many reefs in Hawaii are in protected areas, there are some places where currents and/or surge may create cause for concern.
Did the Hawaiian people use coral for anything?
Hawaiians did recognize and respect the reefs. In the Kumulipo (the Hawaiian creation chant) the first creature that emerged (after man and woman )was a coral polyp. Hawaiians used coral skeletons for tools, and rubble for both game pieces and trail markers. They also discovered medicinal uses for coral tissues and toxins.
Can you share any other facts with us about coral?
Sure – the coral animal has a mouth and a stomach, but no anus. So when the animal poops, the poop comes out of its mouth!
Most corals need something to hang onto to start their colonies. That’s why you see a lot of sandy patches in our bays and harbors devoid of coral. Coral will grow on a rock, a line, a boat (if it’s not moving) and even your sunglasses if you drop them in the water – but it can’t grow in sand!
