IN TOUCH WITH NATURE

Otago Daily Times, Issue 22268, 22 May 1934, Page 2

IN TOUCH WITH NATURE

By J. Deujimosd, F.L.S., F.Z.S

NATIVE FROGS CLIMB TIH3ES AT NIGHT.

New Zealand is a suitable abode for amphibians, but i 3 poor in these coldblood creatures which, contrary to popular belief, cannot live in water or air at will, but live only in water in early life and only in air in later life. Two' species of frogs, as far as is known, compose the whole of New Zealand's native amphibian life. One of these Liopelma hoehstetteri, lias for its territory the Coromandel Peninsula and a few other places in Auckland Province. It has been known for many years, but was considered rare. Mr C. E. Clarke, a member of the staff of the Auckland Museum and Mr A. Richardson, while doing entomological field work on high densely-wooded parts of the Coromandel Range last February, who delighted to see many individuals of the species. They could have been collected a hundred or more during the two weeks they spent there. The frogs seem to have become more plentiful since their enemies, the wekas, almost disappeared from the district.

" They arc seldom seen in the daytime except by diligent 6earch," Mr Clarke writes, " but by the light of our collecting lamps we found them plentiful at night, when the forests are awake. The little fellows can climb tree trunks. Along obscure forest tracks we saw them climbing with the precision of gymnasts. It was interesting to watch them taking hold with their shapely lingers and ascending hand over hand. The thought came into my mind that man evidently learnt to walk on his hind limbs by using his hands in the same way. It is not surprising that philosophers have praised the development of the hand as a factor in human evolution.

" This species of frog has another interest. The genus Liopelma is found in South-east Europe, North Africa, China and other parts of Asia, and is an important link in a chain of evidence of a former land connection that joined New Zealand to Asia. The geographical distribution of Placostylus, a genus of laud shells, is another study of this native. It is present on islands of the Melanesian Plateau. The numbers of species in different places are: New Zealand, two; New Guinea, Lord Howe Island and Santa Cruz, one each; Loyalty Islands, six; New Hebrides, nine; Fiji, 16; Solomon Islands, 17; New Caledonia, 34. The different species could have differentiated by only long isolation. Their distribution evidences former land connection between these places. It is very interesting to trace on a map the extent of the old Melanesian Plateau, and to conjucture the shape of the submerged continent.

The Australian green frog has been successful in New Zealand. In view of this, New Zealand's poverty in native species is very surprising. More surprising is the fact that, although toads are distributed over almost all the world, New Zealand has none. The common toad of the Old Country and of Europe was introduced into Canterbury 67 years ago and into Gisborne 41 years ago, but it did not succeed in establishing itself. New Zealand is toadlcss as well as snakeless. A few hundred years ago, when the toad was a victim of all sorts of wild superstitions, this would have been a matter for congratulation. In these days it is regarded as regrettable. The toad is ugly, but its breath and its spittle Eire not poisonous, having no salivary glands it docs not discharge spittle, it does not turn wine to vinegar, it does not cast spells over men and beasts, it docs not possess the evil eye, it does not drive dogs mad, its glance do<?s not make people turn pale, it is not malevolent, repulsive and loathsome. It lives mainly on caterpillars and on grubs of beetles. Strictly carnivorous, it does not attack plants. It is a harmless and useful citizen, a welcome member of any country's population, especially as a lodger in the garden.

The fecundity of the common toad is set out in a translation, received a few weeks ago, of a toad book by a French writer, M. Rostand. He estimates that a female toad lays about (iOOO eggs a year, and that if each egg produced a tadpole, and each tadpole a toad, and if such toad reached the age of reproduction, in a few years toads would be numbered in billions; neither earth nor water would hold them. Nature frowns upon the possibility. She inflicts death on toads with a heavy hand. Weather and temperature often prevent their eggs from developing. In their youth, as tadpoles, they are destroyed by birds and insects. Water beetles and water boatmen, so ferocious that they are called pond sharks, try to satisfy their prodigious appetites on tadpoles. Adult toads are beset by perils at every turn. Only a few individuals complete the life cycle from embryo to adult.

Toad tadpoles are hearty feeders. They are omnivorous, but prefer a flesh diet. When food supplies are short they will eat one another. If necessary they can go without food for a fairly long time and be none the worse, except that semi-starvation retards their growth. In captivity they live without nourishment for weeks, 51. Rostand is convinced that the toad is not stupid. Its bump of curiosity is highly developed. It has a sense of direction. It is smarter than a frog in finding its way in a maze. It changes its habits quickly. It is easily tamed. A toad was kept in France for 36 years. It was placed on the table every night to have a meal. It lived near the house, and as soon as it saw a light in the window it came to be fed. The difference between a toad and a frog is not.sharply defined. A toad may be distinguished by its squat, thick-set figure and its warty skin.

, Toads as well as frogs have been found shut in walls and rocks. There is a mystery about this that seems to defy explanation. In experiments, toads were suffocated fairly quickly if completely deprived of oxygen, but their breathing requirements were very slight. This brings to mind the strange experience of Mr G. M. Thomson in Dunedin. An Australian green frog lived in a large case filled with ferns, which stood in the hall of his house. He went for a tour of the North Island, and was away, for six weeks., On his return most of the ferns were dead. The case was taken into a shed. At the end of 12 months, wishing to restock the case, Mr Thomson began to empty out the old material, which was quite dry. He searched for (he frog's skeleton, but could not find it.

On the bottom of the case, under a large dead fern, there was a lump of clay, dry on the outside. On breaking this up he saw the frog inside. It was alive, and cool and moist, and looked very much the same as when be left it 15 months previously. It was placed in a glass vessel. When a house fly was shut in the vessel the frog immediately came to attention and caught the fly and ate it. As far as Mr Thomson could remember, the ball of clay that form-'.d the frog's prison was not in the case originally. The frog seems to have gathered the clay somehow; but Mr Thomson could not explain how it got inside the ball and apparently left no aperture. It was not imprisoned in rock, but it .vas in a remarkably hard piece of clay, yet it breathed and retained its moisture for 15 mouths.

While toads have been blamed unjustly for many things, they are poisonous. They sweat a poison which keeps their skins moist. Under pressure of agony or provocation they emit another poison, but not often, and only with difficulty. A small quantity of the second poison, in a dry form, administered to a dog, caused death. Agitation, copious discharge of saliva, hallucinations, laboured breathing, and fever preceded exhaustion, drowsiness, paralysis and weakened heart-beats. Rats and rabbits are less sensitive than dogs and cats to this poison. When handled, a toad may eject a transparent liquid. This is harmless. Neither of the poisons is regarded as dangerous to human beings, as toads cannot introduce them into people's systems. A toad's blood, injected under a frog's skin, killed the frog in half an hour. A toad resists poisons that quickly kill frogs. It survives doses of poison from spiders that will kill four guineapigs. To the poison of a salamander, it shows 40 times as much resistance as a cat does. With all their poison, toads, in some countries, are eaten by human beings, who regard the flesh as delicate.

Whalers preceded the colonists in New Zealand, and made an important chapter of the colony's early history. Spcarm-whaling began 130 years ago. About 30 years later the number of sperm-whales in New Zealand waters have decreased seriously. The southern right-whale then was sought. The rightwhale industry was conducted 6idc by side with the sperm-whale industry. It became the more important of the two. In 1840 there were between 600 and 700 American whaling vessels around the New Zealand coast. This is about half the total for all nations. The right-whale industry then began to decline. It went down hill until it was insignificant. Two small stations, one at Whangamumu, Bay of Islands, the other in Tory Channel, Queen Charlotte Sound, are the only remaining representatives of the former great activities. The rise and decline of whaling in New Zealand is sketched in the latest report of the Discovery Committee, London, issued on behalf of the Government of the Dependencies of the Falkland Islands, where investigators on Discovery II are conducting valuable research into whaling and the habits of whales.