THE TUATARA

Dominion, Volume 30, Issue 158, 1 April 1937, Page 13

THE TUATARA

Will It Become Extinct? NUMBERS GROWING LESS It sometimes is said that the tuatara is the oldest animal in the world. This statement may be given more than one meaning; but whatever is intended by the expression probably is wrong. If, for instance, it is meant that the ancestors of the tuatara go further back in geological time than do those of any other living animal, then this is not near the truth; for some animals such as Roman lamp shells or brachiopods had close relatives living when the oldest fossiliferous rocks were laid down. This epoch, known as the Cambrian, judging by tests for radio- activity of the rocks, would be over live hundred million years ago. But the known ancestors of the tuatara are found at a much later date, namely, in the Triassic period, or about two hundred million years ago.

If, on the other band, the question as stated above means that the tuatara as a species existed longer than any other species, then the answer is that, actually, there are no fossil records of the tuatara whereas many kinds of recent shellfish are known to have lived in the Tertiary era perhaps twenty million years ago. Preludes to Extinction.

In view, however, of the undoubted ancient character of the tuatara, that is to say, the fact that it possesses features that were common in the Triassic period, we may wonder why it has preserved these characters and whether it is on the verge of becoming extinct. The question: .“How do species of plants and animals become extinct?” is easily answered to-day. Obviously it is that man, by his exploitation of the earth, is killing them off by transplanting harmful animals to new areas, by hunting them for their products or by using their natural habitats for his own purposes.

But long before man peopled the earth large classes of plants and animals became extinct. At the end of the Secondary era, for instance, the large reptiles called dinosaurs, and the spiral shellfish called Ammonites, which existed in great variety, became extinct. Generally, the over-develop-ment of useful characters to the point of becoming a hindrance, is a prelude to extinction. The dinosaurs and several large kinds of mammals developed large horns and other structures before they finally died out. Slow Kate of Living. What, then, are the causes that led to the tuatara having a long specific life and thus earning the distinction of a living fossil; ami is it showng signs of dying out? The main character that seems to give the species eternal life is its slow rate of living. Its vital organs seem to function very slowly so that food and air are not required at the same rate as is usual in other animals. Even Ihe eggs take more than a year to incubate. They are laid in November, hibernate from March to September, and hatch out the following December or January.

Perhaps this retarded vitality is the main cause of individuals living (according to evdcnco of the Maori) up to three hundred years. At this rate, the tuatara, if left alone, undoubtedly is certain to last for a long time: but it is no less certain that its numbers are becoming less. Thus, before tlie European came with his fire and his animal associates, the tuatara was found on tlie main islands, near Wellington,- in Taranaki, in Hie Bay of Plenty district, and north of Auckland. Now it is restricted to outlying islands where in some instances its numbers have been reduced tlfrough clearing for settlement ami by cats and dogs. Contributed by tub Dominion Museum. (Picture on Page !).)