National Geographic : 1940 Jun
WHERE NATURE RUNS RIOT On Australia's Great Barrier Reef Marine Animals Grow to Unusual Size, Develop Strange Weapons of Attack and Defense, and Acquire Brilliant Colors BY T. C. ROUGHLEY A STRALIA'S Great Barrier Reef is one of the outstanding natural wonders of the world. Largest of all coral reefs, it stretches for 1,250 miles along the continent's northeast coast. The reef is a region of strange contrasts. Animal life of rare beauty mingles with forms that are ugly and repulsive; giants lie side by side with their pygmy relatives; boldness and ferocity contrast strangely with extreme delicacy and sensitiveness. Nature appears to have thrown discretion to the winds and run completely riot.* On the way to Heron Islet from the mainland we sighted our first coral isle. It appeared as a low mass of dense vege tation surrounded by a snowy white beach. Heron Islet is a coral cay about a mile in circumference and is typical of scores of islands throughout the Great Barrier Reef (map, page 827). Each is usually more or less surrounded by an oval rampart which may be many miles in extent and is ex posed at low tide. It is amazing to con template that all these hundreds of miles of islands and reefs have been built up by tiny animals, the coral polyps, which take lime out of the sea water to form their stony skeletons. STRANGE CREATURES OF THE CORAL Of course the most conspicuous feature of the reef is the coral itself, almost infinite in its variety, form, and color. But it is rarely brilliant; rather does it exhibit its beauty in subdued tones, which range the length of the spectrum, and it serves to throw into stronger relief the bright hues of the fishes and clams (see Color Plates). Yet not all the fishes are beautiful. In deed, the Barrier Reef harbors one that may rightly be regarded as the world's ugliest fish-and most poisonous, too. Known as the stonefish, it is about as loath some as any creature on land or in the sea. Its slimy body is just a mass of warty excres cences; its wide, upwardly directed mouth is a sickly green inside; its movements are sluggish and altogether lacking the grace of other fish. But if Nature has treated it abominably in the way of looks, one can almost imagine that the stonefish has made an effort to retaliate by subjecting to a painful death every living thing that touches it. 13 UNLUCKY SPINES Along the back are 13 spines, each as sharp as a needle, each provided with two venom glands, each effectively concealed by innocent wartlike coverings. Normally, these spines lie flat, but the moment they are touched they stand up, erect and rigid. As they penetrate the flesh, the venom is carried along grooves in their sides to enter deep into the punc tured wound. The venom is probably a nerve poison; there is no known antidote, and it causes a prolonged agony that is well nigh unbearable. Effectively armored and camouflaged as it is, the stonefish makes no attempt to dash for cover at one's approach. Lying still amid the coral and harmonizing with its surroundings in color and contour, it simply waits and watches as if secure in the knowledge of the fate that will over take those who dare to molest it. Visitors to the reef can be assured, how ever, that with heavy soles on their shoes the possibility of poisoning by stepping on a stonefish may be forgotten. But let us leave this loathsome creature and pass on to a subject more pleasing, the butterfly cod. Many fish are more brilliantly colored than this, but for comeli ness and grace none can surpass it. The butterfly cod is never in a hurry; it moves slowly about with a quiet dignity reminiscent of the peacock. What a con trast is this pride of the pool to the stone fish! Yet both belong to the same family. If the stonefish is the most horrid fish of the reef; if the butterfly cod is the most beautiful, then the mudskipper, or walking * See "The Great Barrier Reef and Its Isles," by Charles Barrett, in the NATIONAL GEOGIRAPIII( MAGAZINE for September, 1930, and "Coral Castle Builders of Tropic Seas," by Roy Waldo Miner, June, 1934.