NATURE NOTES.

New Zealand Herald, Volume LXIV, Issue 19702, 30 July 1927, Page 1 (Supplement)

NATURE NOTES.

GECKOS AND THEiR HABITS.

BY J. DRUMMOND, F.L.S., T.Z.3.

The green gecko lizards are so variable in their ' colours that a beautiful yellow one caught by Mr. D. H. McKenzie, of Milford, is not very surprising. The particular species to which the gecko belongs, well named Naultinus elegans, usually has a background of green on its upper surface, with white or yellow spots, while its lower surface is yellowish white. Mr. McKenzie's individual was not only conspicuous by its yellow coat, but also was larger than most of its species, measuring five inches and a-half. The rarest lizard in this Dominion is a greenish grey gecko, with irregular purplish bands on its back. Naultinus elegans, popularly known as the spotted lizard, is fairly plentiful in both the North and South Islands.

Geckos are not true lizards. Most of them havo adhesive pads on their fingers and toes. With these, they can climb on smooth and vertical surfaces, like a window-pane. Some even can crawl upside down along a smooth whitewashed ceiling. For this " stunt" they use an apparatus described as complicated in its minute detail/ but very simple in principle. The adhesion is not by means of a sticky substance, but by vacuums. On each finger or toe there are many small plates or scales. When the foot is pressed down on a smooth surface these are caused to spread asunder and to drive out the air. On account of their elasticity, they return to their original position, and vacuums are produced. Each little plate or scale has smaller hair-like excrescences, which secure close pressure to the slightest irregularity of "the surface, and add to the elasticity of the pads. Geckos that live on sandy, barren ground, usually are devoid of adhesive pads, and their fingers and toes are narrow.

Naultinus utters a chattering sound, believed by Maoris to be a laugh. This probably, resembles the word " gecko," which is uttered by some species of geckos in other countries, and which has given the whole group a name. Other species use a sound like " click" or " chick." Most geckos lay white, hard-shelled, slightly oval eggs, but Naultinus elegans produces its young alive. A female sent from Pleasant Point, near Timaru, to Christcburch, some years ago, gave birth in captivity to two pretty all-green baby geckos. The whole family was liberated in an orchard. The geckos' prehensile tails are used in climbing trees. In New Zealand, geckos have been known to remain motionless for hours, but they sometimes take up strange and grotesque positions. They run quickly, with an undulating movement of their tails. They like water, and swim very quickly, but clumsily, as if they are in great haste.

Insects are the main food of geckos The Rev. W. Colenso watched a New Zealand gecko attack a fly. When it saw the fly, and was sure that the fly was alive, it stealthily crept up. When within two inches, it arched its back to a fairly sharp angle. Its eyes swelled and bulged upward over their orbits, and its countenance took on a fiercer look. Raising its little hand-lika paws, it moved a toe or a finger at a time, often in the air, very slowly and cautiously, as a little child moves its hands when stealing along on tip-toe. It thrust its bead toward the fly, but so slowly that Mr. Colenso detected the movement best by watching its shadow on marked paper. The movement reminded him of the almost imperceptible movement of the hourhand of a clock. . It advanced within about an inch, or less, of the fly. It made a dart like a flash, and the fly was caught. It shook the fly rapidly from side to side like a terrier with a rat. Half opening its mouth it gulped the fly whole, legs, wings and all.

Mr. Colenso found that ifc was a pretty sight to see geckos drinking. They lap water like a cat laps milk, but ver}* slowly; as if they are merely tasting. They occasionally pass their broad, thin, large, purple tongues over their eyes as if they were washing them, and always finish drinking in that way. Mr. Colenso's geckos often went into their water trough, and for some time remained extended in the water. Sir Walter Buller is the authority for a statement that the gecko's laugh was enough to terrify the bravest Maori warrior, and that members of all tribes in all parts of New Zealand attributed evil powers to the geckos. This groundless dread is shared by many people, barbarous and civilised. In some countries geckos are feared more than poisonous snakes." They are absolutely harmless They may try to bite a person's finger, but their tee*,h do not penetrate the skin. If not molested, they become tamo and confiding.

A gecko's only defence when caught is to leave part of its tail in the hand, claw, or jaw of its captor. The new tail it produces from the stump is like the old one. Portuguese geckos that lost their tails when they were caught were kept in a box without food for six weeks. When they arived at their destination in England, each had grown a new stump about half an-inch long. In an officer's quarters in the fort at Colombo, many years ago, a gecko was taught to go to the dinner table daily. It always appeared with the dessert. While the family were absent for seeral months, the house was extensively repaired, the roof being raised, the walls stuccoed, and the ceilings whitened. It was believed that the little lizard, after such a long suspension of its custom, would disappear; but when its old friends came back to their home, it attended at their first meal, as soon as the cloth was removed. The largest and handsomest gocko is claimed by couutries in South-eastern Asia. It is fourteen inches long, and it light bluo, with red or orunge spots. The Malay Archipelago has a gecko equipped with an expansion on each side of its body, which it uses in parachuting from one tree-trunk to another. New Zealand's commonest lizard, the mokomokoj which often lurks under Stones and logs in the bush, and in the open country, is a skink, or true lizard. Usually, its back is reddish brown, with a whitish stripe, edged below with black, and often with a dark stripe down the middle of the back, but sometimes it is pale golden-brown on the back, and darker on the sides. A black or brown lizard found on shingly beaches is another skink. Some twenty-three years ago, Mr. E. A. Hodges, Waitekauri, amused himself by doing a little gum-digging near a small farm owned by Mr. J. Mitchelson, behind Dargaville One dry summer, when turning over stiff soil in a small depression, which had been muddy in the wet season, he was surprised to find three fish, about four inches long. They were in a small pocket. There was no water, and the soil was not even moist. The mud-fish were lively, and wriggled about. A correspondent who saw a songthrush's nest on June 25 last, asked jf this species has been known to nest in New Zealand as early as that in any previous season. Mr. T. S. Mason, of Hamilton, states that at East Taieri, in 1916 or 1917, he found a song-thrush s nest with three eggs in it on June 3.