Art. XVII.—Notes on the New Zealand Bats.
[Read before the Auckland Institute, 28th August, 1893.]
One of the most remarkable peculiarities of the fauna of New Zealand, and one which has been much commented upon, is the paucity of indigenous land-mammals. Only four have been catalogued—the dog, or “Maori dog,” as it is usually called, the native rat, and two species of bats. And if we examine the subject carefully we shall find very good cause for believing that the two bats are the only land-mammals which can undoubtedly prove their claim to be considered aboriginal inhabitants of New Zealand. Take the case of the
dog: The early voyagers and first residents of New Zealand all agree in stating that the Maori dog was unknown in the wild state. It was a purely domesticated species, fed by the Maoris on fish and refuse offal, and valued by them for two reasons—for yielding a dainty article of food, and for supplying the material for their much-prized dogskin mats, or providing them with hair for the ornamentation of their taiahas or other weapons. Before the arrival of Europeans, as Mr. Colenso remarks, a wild dog would have been just as much unknown to the Maoris as a wild sheep would be in England at the present time. The wild dog about which European settlers have talked in recent times is the descendant of curs introduced by the whalers or first traders, and has no resemblance to the ugly, stupid, and inoffensive animal described by Cook and others. In short, all the reliable evidence that we possess respecting the Maori dog goes to prove that it was a domesticated species that the Maoris brought with them when they first colonised New Zealand.
With respect to the rat, the evidence is not quite so clear. It is a much-debated question whether the rat hunted by the Maoris, and so much prized by them for food that intertribal wars have arisen for the possession of favourite hunting-grounds, is living at the present time or not. Mr. Colenso, whose knowledge of the natural history of New Zealand, and close acquaintance with the Maori race, should give great weight to his opinions, believes that no living European has seen the true Maori rat—that it has vanished from the list of living beings, and has become as extinct as the moa or dodo. Others, whose views are perhaps equally entitled to attention, believe that the small black rat still found in forest districts, and on the outlying islands, and which occasionally makes incursions in considerable numbers into the settled portions of the country, is the true indigenous species. But, whichever of these views is correct, a comparison of skulls found in old Maori eating-places seems to have established the fact that the Maori rat was identical with a species widely distributed in Polynesia, and which has been known to have been unintentionally carried by the Polynesian natives from one group of islands to another. The Maoris have a tradition that they brought the rat with them from Hawaiki, and, until remains of the animal have been found in deposits older than the time of Maori occupation, we must attribute considerable weight to that view.
If, therefore, our bats are the only indigenous land-mammals that we possess, considerable interest ought to attach to them. As already mentioned, we have two species which are familiarly known by the names of the short-eared
bat (Chalinolobus tuberculatus), and the long-eared bat (Mystacina tuberculata). The first is much the more common of the two, and can easily be recognised by its short ears and by its long tail, which is completely included in a prolongation of the wing-membrane. It is rather more than 2in. in total length, and is thus about the same size as the pipistrelle or “flittermouse,” the commonest of the English species. The long-eared bat is slightly larger than the species just mentioned; it has much longer ears, and a curious projecting muzzle; its tail is very short, and is almost entirely free from the wing-membrane. A remarkable peculiarity is that a part of the wing-membrane is thickened, the remaining membranous portion being folded under this when the wings are in repose. The wings, when folded, thus occupy a smaller space than in any other bat.
Up to the present time hardly anything has been recorded respecting the mode of life of the New Zealand bats, a circumstance no doubt due to their shy and recluse habits. The English bats, or most of them, frequent the habitations of man, taking up their quarters in churches and cathedrals, ruined towers, and other buildings, or even sheltering themselves in attics or under the straw thatch of cottages. They are thus regularly under the observation of man, and are familiarly known to most country-people. But the New Zealand species are seldom seen. They are pre-eminently lovers of the forest, and are never found far from its dense shade. To study their habits, or even to see them at all in a living state, it is necessary to dwell in the heart of the forest. It is therefore not at all surprising that it has not yet been decided whether our bats live in communities, as is the case with most of the European species and many others, or are solitary in their habits. Many bushmen incline to the latter view, giving as a reason that they hardly ever find more than one or two bats together. The object of this paper is to prove that the first view is the correct one.
In the year 1881 I spent some time exploring the western portion of the Nelson Provincial District. While stopping near the Graham River, a tributary of the Motueka, which rises in the forest-clad hills near Mount Arthur and Mount Peel, I observed that the short-eared bat was remarkably plentiful. Every evening at dusk scores could be seen flitting across the bush-clearings, and I was much interested in watching their zigzag flight, and in noticing the ease with which they caught their insect prey upon the wing. Conversing about them with the keeper of the accommodation-house, I learned that a bushman called Deacon had lately found a colony of many hundreds in a hollow tree in the Wangapeka Valley. A few months later I visited Wanga
peka, and sought out this man, obtaining the following account of his discovery. He was at work with his mate cutting rimu timber for mining purposes. They had selected a tree for felling, but after cutting some distance into it had found that it was hollow, and had therefore decided to leave it and pass on to another. Accidentally they noticed that some bats were flitting about the trunk of the tree, and they soon found that they were emerging from a hole leading from the hollow interior, no doubt having been disturbed by the blows of their axes. Some bunches of dried grass were set on fire and thrown into the cavity, which they also probed with a long rod. The result was that they disturbed an immense number of bats—according to them, several hundreds. They emerged from the hole in a continuous stream, flitted round about the tree in an aimless manner for some time, several remaining an hour or more in the vicinity, but at length disappeared into the adjacent forest. The interior of the tree was slightly charred by the burning grass which the men had thrown into it, and apparently this deterred the bats from resuming possession of their home, for on visiting the tree some months afterwards not a single bat could be found.
Several years after this my friend Mr. J. W. Hall, of the Thames, wrote informing me that some bushmen had found a considerable number of bats in a hollow tree, and that several of them were in the possession of Mr. Price, a local taxidermist. I succeeded in obtaining two of these specimens from Mr. Price for the Museum, and from him and from Mr. Hall I gathered the following particulars of the find: Some four or five bushmen had proceeded to Kerikeri, a few miles from the Thames, for the purpose of collecting wild honey. They found a hive, and cut open the tree to take the honey from it. In doing this they dislodged a considerable number of bats. The number was not estimated; but, as each of the men carried home several, one man in particular having a kerosenetin filled with them, it must have been large, more especially as the men stated that what they caught was only a small fraction of what escaped. The species was the short-eared bat.
I have now only one other instance to mention. A few months ago a man who gave his name as McDonald came into my office with a box containing twenty-two living bats. I purchased them from him for a few shillings, and he gave me the following account of how he obtained them: He and another man were engaged in bushfelling near Reweti, on the Kaipara Railway. They cut down a tree, the upper portion of which was loaded with creepers and epiphytes. When the tree fell and struck the ground the men were amazed to see numbers of bats fly from the upper branches. Running to
the spot they found that clusters of them were still clinging to the branches. They collected about thirty, and could have obtained very many more had they wished. They did not notice that the tree was hollow, and were of opinion that the bats were simply sheltered by the overhanging creepers and epiphytes.
Being anxious to see how they would behave in a room, I closed the doors and windows and liberated them. They took to their wings at once, and commenced to circle round the room with that quick, soft, and noiseless flight which is always so noticeable. The presence of full daylight did not affect them in the slightest degree, for they never made a mistake in estimating their distance from an object. They circled round the room, flying in and out of the corners, skimming just below the ceiling, and hovering over the furniture, but never came into contact with anything. It is worth mention that they did not dash themselves against the window-panes, as a number of birds would have done under similar circumstances, but treated the glass in precisely the same manner as the walls of the room. This fact lends support to the view now generally adopted that much of the power possessed by bats of directing their flight in complete darkness or strong sunlight is due to an exceptional development of the sense of touch, residing specially in the great membranous expanse of the wings. After satisfying themselves that there was no mode of escape from the room they commenced to settle down on the tops of the architraves of the doors and windows, hanging head downwards by the claws of their hind legs. They ultimately collected into little clusters of four or five, cuddling quite close to one another, and were then easily caught and transferred to their cage.
The above facts will make it quite clear that our bats are by no means solitary in their habits, but dwell together in communities, often numbering several hundreds, and usually occupying the hollow interior of some aged forest-tree.
Postscript.—Since the above was written I have seen Sir W. L. Buller's paper on the same subject, printed in vol. xxv. of the Transactions. I am glad to notice that the evidence he has collected is quite in accordance with the facts given above.