WAYS OF THE WILD.

Auckland Star, Volume LXVI, Issue 46, 23 February 1935, Page 1 (Supplement)

WAYS OF THE WILD.

THE SEA IGUANA.

FEEDS ON SEAWEED.

(By A. T. PYCROFT.)

Iguanas are lizards found in tropical America and the West Indies. The sea iguanas, or lizards, are the largest of the iguanas and may measure up to four feet in length. They are confined to the various islands of the Galapagos group, where they are extremely common on the rocky coasts. A well marked crest runs from the nape of the neck to the tip of the tail, and the whole build of the animal is stout and chubby. In colour this lizard is black, or blackish brown above, with the abdomen and inner surface of the thigh not infrequently dirty white. Darwin, writing of this lizard, says it swims with perfect ease and quickness by a serpentine movement of its body and flattened tail, the legs being motionless and closely collapsed on its sides. A seaman on board the Beagle sank one with a heavy weight attached to it, thinking thus to kill it directly, but when, an hour afterwards, he drew up the line, it was quite active. Their limbs and strong claws are admirably adapted for crawling over the rugged and fissured masses of lava which everywhere form the coast. In such

situations a group oi' six or seven of these hideous reptiles may oftentimes be seen on the hlack rocks a few feet above the surf, basking in the sun with outstretched legs. After mentioning that the. stomachs of several that were examined contain finely minced seaweed, and also observing that the

droves seen swimming out to sea were doubtless in search of food of this nature, Darwin states that when frightened these lizards absolutely refuse to enter the water. They do not seem to have any notion of biting, but when frightened they squirt a drop of fluid from each nostril. Darwin threw one several times as far as he could into a deep pool left by the retiiing tide, but it Invariably returned in a direct line to the spot where he stood. It swam near the bottom, with a very graceful and rapid movement, and occasionally aided itself over the ground with its feet. Even when driven down to the water it would not- enter, although possessed of such wonderful powers of diving and ' swimming. Daiwin thought it was reluctant to do so because it had no enemy wliatevei oil shore, whereas at sea it must often fall a prey to the numerous sharks. Strangeness and Tameness, William Beebe, Director of the Department of Tropical Research of the New York Zoological Society, visited the Galapagos Islands in 1923. These islands were first discovered by Europeans in 1535, and first visited by a scientist when Darwin spent five weeks in the group in 1835. Only five weeks, but five weeks of Darwin's eyes aul Darwin's powers of observation aul reasoning were equivalent to a whole previous cycle of human thought. 11'- : was then only 26 years of age. From then -until Beebe arrived, 88 years later, the mind and spirit of man have remained exactly the same, while a wonderful development has taken place in man's intellectual and mechanical environment. Beebe,. with his trained staff of young naturalists, spent less than 100 actual hours on land, but they brought together an unparalleled accumulation of facts, many of which an; published in Beebe's book, "Galapagos. Referring to the sea iguanas, or us Beebe calls tliem, "black lizaids of to,! surf," he states: "Within two days we realised that these islands were stiil in the age of reptiles. Giant tortoiseand land iguanas dominated tlie upper parts of the island, but the shores we; - held by the big black iguanas, which, more than any creature I have seen, except the hoatzin, brought the fat distant past vividly into the present." We in New Zealand have also, in the tuatara, a link with these ancient times. Some of the large Galapagos sea lizardsweigh as much as 201b. Beebe consider.tliat the two dominant qualities of the Galapagan fauna are its strangeness anJ tameness, and this was especially noticeable in the case of the sea iguanas. Their land haunts are within a few yards of high tide and their aquatic wanderings not far from the shore. In this nano.v zone they spend their entire lives, finding food, safety and water within its confines. Neither drought, nor seasons, nor food supply require any migration. A burrow, a flat rock, a tnft of sea weed and Amblyrhynchus, or the sea iguana, is content. They weie frequently seen swimming across the calm waters of the wide but shallow coves. Whatever the type of shore they chose, the one necessity was seaweed, and whenever an iguana or a whole colony were seen low water was certain to reveal tufts of the olive green sargassum. They were so tame that they were often almost stepped on. The World's Only Sea Lizard. These giant marine iguanas have strong claws, but are good tempered and never attempt to bite. Their daily life is very simple. They spend the nights in their burrows in the earth, or deep down.in lava ereviecs. About eight or nine o'clock in the morning, if the sun is shining, they come out anu wait, for low tide, then, making their way slowly to the edge of the surf, they feed on the short glutinous algae. Afterwards they sometimes bask all day in the sun on some favourite rock out of reach of the water, individuals going back day after day to the same spot. They were never seen out at night, not even in full moonlight at low tide. They feed but ouce a day. They have never been seen to dive for food, and there is no need for it, for at ordinary times an abundance of the seaweed is always exposed, as this growth thrives only where there is active surf, so the feeding reptiles are often completely covered three or four feet deep, by an incoming wave. At such times they grip tight with their claws, and they were never seen dislodged. One of their most peculiar habits is ejecting a thin shower of water vapour into the air through their nostrils. This is done when angry. These great lizards an; provided with a mail of scales, which become like solid masonry around the head, with a formidable saw-like ridge of horny teeth and powerful jaws with twenty long, curved talons, backed by incredibly strong- muscles, and yet with no desire or power of defence, no liitinji or clawing or lashing of the tail. Nothing is known of their breeding habits or to what ag'i they live