RODENTIA--RATS.
The gnawing-animals, which constitute the order Rodentia, form the most
sharply defined group of the Mammalia, the distinguishing characters
and name being derived from their teeth. These are of two kinds
only--viz., incisors and grinders--there being two efficient incisors
in each jaw, and from three to six molars. There are no canine teeth
at all; consequently it is easy to recognize the skull of a rodent by
its dentition. The animals are mostly small, the beaver being about
the largest; while some kinds of mice are hardly more than a couple of
inches long.
Seven species of rodents have been introduced into this country at one
time or another. Of these, three species of rat, the mouse, and the
guinea-pig belong to the simple-toothed rodents--that is, they never
have at any period of their life more than two incisors in the upper
jaw. The rabbit and the hare belong to the double-toothed rodents.
These have each two large incisors in the upper jaw, and behind them
two small--almost rudimentary--incisors.
A species of rat was one of the four land-mammals occurring in these
islands when Captain Cook first visited New Zealand, the others being
a dog and two species of bats. Sir Joseph Banks says in his Journal,
“On every occasion when we landed in this country we have seen, I had
almost said, no quadrupeds originally natives of it. Dogs and rats,
indeed, there are--the former, as in other countries, companions of
men, and the latter probably brought hither by the men. Especially as
they are so scarce that I myself have not had an opportunity of seeing
even one.”
This was not Forster’s experience, for in his account of the second
voyage of Cook (in 1773) he says, “Our fellow-voyagers [Furneaux in the
‘Adventure’] found immense numbers of rats upon the Hippah Rock [Queen
Charlotte Sound], so that they were obliged to put some large jars in
the ground level with the surface, into which these vermin fell during
the night by running backwards and forwards, and great numbers of them
were caught in this manner.” It is now almost certain that this native
rat was the same species (_Mus exulans_) as is still common in many
of the South Sea islands and throughout the Pacific, and it probably
came with the original immigrants, the ancestors of the Morioris and
Maoris. It is, however, probable that the common European black rat
(_Mus rattus_) came also into the country with the various ships which
touched at these shores from 1769 onwards. Indeed, Yates, who wrote in
1835, says, “The Natives tell us that rats were introduced in the first
ship by Tasman.” He is certainly not an authority on the subject, and
too much importance need not be attached to his statement; but it is
nevertheless interesting. In Cassell’s Natural History, Dallas, who
writes on the Rodentia, says, “New Zealand at the time of its discovery
harboured a rat known as the forest-rat, or Maori rat, which was a
favourite article of food with the Natives, and is now almost extinct.
It has been proved by Captain Hutton to be identical with our black rat
(_Mus rattus_), and was probably introduced by the ancestors of the
Maoris.”
I do not know when this was written, for Messrs. Cassell and Co. take
the precaution not to put dates on many of their books. But Hutton,
in vol. 20 of the “Transactions of the New Zealand Institute” (1888),
speaks of the rats which invaded Picton and the Marlborough Sounds as
_Mus maorium_, and says, “This rat is certainly different from _Mus
huegeli_, from Fiji, and, I should think, from _M. exulans_.” The
whole subject has recently been investigated by Oldfield Thomas, who
is the greatest living authority in this group, and he is certainly of
opinion that the kiore, or Maori rat, was the common Pacific species,
_M. exulans_. Endless confusion occurs, however, among early writers in
speaking of rats and their species, and this must be borne in mind in
reading the accounts of these animals.
The Rev. R. Taylor--who is not always, however, a reliable
authority--says that this Maori rat was in general size about one-third
that of the brown, or Norway, rat. The Maoris used to make elaborate
preparations to catch them, and hundreds of them would be captured at
one hunting. He says the animal is reported to run only in a straight
line, and that the Maoris made special lines of roads in order to lead
them into their traps, which were baited with miro and other berries.
If these roads were crooked, they said, the rats ran into the forest
at the bends. They fed entirely on vegetable matter, and were greatly
prized as food by the Natives, who also extracted much oil from them.
The native rat quickly disappeared before other rats and also cats;
it was extremely rare thirty or forty years ago, and is probably
quite extinct now. As, however, the species is common in Polynesia,
occasional immigrants may arrive in New Zealand from time to time.
The popular belief among both Maoris and Europeans was that it was
exterminated by the Norway rat (_Mus decumanus_). It is, however,
probable that the latter is a more recent immigrant than the old
European black rat, which is still an extremely common animal here.
That the Maori rat was once very abundant seems to be proved by the
fact that the Natives always erected their storehouses for food on
various kinds of piles as a protection against the depredations of
these animals. This habit, according to Judge Mailing (“Pakeha Maori”),
was the custom before Europeans landed in the country.
Tancred, writing of Canterbury in 1856, says, “The native rat forms
numerous burrows, rendering the soil unsafe for a horse.” He also
repeats the statement about its being exterminated by that formidable
invader the Norway rat. Mr. W. T. L. Travers, writing in 1869, says,
“It has been the fashion to assume that before the arrival of Europeans
in this colony this creature [the native rat] was common, and to
attribute its destruction to the European rat; and, indeed, the Natives
have been credited with a proverb in relation to this point. It is not
in effect impossible that the ultimate destruction of those which still
existed when trade was first opened between Europeans and the Natives,
long after the colonization of New Zealand, may have been hastened by
the introduction of the European rat; but I am satisfied that before
that time they had become very scarce, and, indeed, I have been told
by gentlemen who have lived in the northern part of this [the South]
Island for upwards of forty years that they never saw a specimen.”
Speaking of Nelson in 1842, Judge Broad said, “Native rats were an
intolerable nuisance; they ate everything, ran about the houses in
the dark, and had no fear of man. They drove the cats away, and only
disappeared when rat-killing dogs were introduced.” I do not think
these were native rats at all, for the latter ate only vegetable
matter, and these vermin seemed to eat everything.
Dr. Hocken has an interesting statement in his “Early History of New
Zealand,” as follows: “In 1840 Messrs. Dodds and Davis, of Sydney,
established a farming settlement at Riccarton, close to where
Christchurch now stands, and sent down James Heriot (or Hariot) as
manager, two farm hands, and two teams of bullocks. They ploughed and
cultivated about 30 acres of land and secured their crops. But in less
than a year they decided to abandon all further efforts. Numberless
rats attacked the garnered stores, and the bar at the mouth of the
river or estuary proved a sad obstacle to shipping whatever grain had
been spared by the scourge of rats.” We do not know now which species
this was, though I think it was probably the black rat.
It is rather interesting that in 1870 Sir Walter Buller wrote a
paper “On the New Zealand Rat,” and he both figured and described
the European black rat (_Mus rattus_). I have already said that this
rat probably arrived with some of the first ships which came to the
country. Oldfield Thomas in a paper written in 1897 in the “Proceedings
of the Zoological Society” says that the rats normally inhabiting ships
are not, as is commonly supposed, _Mus decumanus_, but _Mus rattus_,
and in most cases these are of the grey variety of that animal, with
white belly, though the black form may often be caught in the same ship
as the grey.
The black rat became enormously abundant in the early days of
settlement, and moved about the country in vast armies. The settlers,
bushfellers, and sawmill hands of fifty or seventy years ago recorded
how invasions of them in countless swarms used to move through their
district, climbing everywhere, and eating everything before them that
was of a vegetable nature. Oldfield Thomas, in the article already
referred to, says, “All the world over _Mus rattus_ takes to roofs and
trees on meeting its formidable rival, _Mus decumanus_, to which it
leaves the gutters and cellars.”
In early days in Southland we often heard about rat invasions, and the
popular belief then was that these were migrations of native rats.
I think there is little doubt that they were black rats, which are
not necessarily black-coloured. I propose to quote now from various
writers on the subject, to show how common these rodents were at times.
Taylor White states that on the west coast of the South Island they
came in vast crowds, climbed trees, tent poles and ropes, and ate
everything. On the shores of Lake Wakatipu they lived under the dead
leaves of the wild-spaniard or spear-grass (_Aciphylla squarrosa_ and
_A. Colensoi_).
[Illustration: FIG. 12.--THE BLACK RAT.]
Rutland records how, in 1856, the district of Collingwood, on the
western side of Blind Bay, was visited by a swarm, and in 1863 he
was informed of a swarm on the Shotover, Otago. I have heard of this
one also. Old miners used to tell how they were nearly eaten out of
provisions by an invasion of rats. Repeated swarms occurred in Picton
in 1872, 1878, 1880, 1884, and 1888. Rutland says, “These rat-swarms
invariably take place in spring. A few of the animals appear in August;
they increase in numbers till November, when all disappear again
gradually as they came. While in a locality dead rats are seen lying
about in all directions--on roads, in gardens, and elsewhere. Very
few have any marks of violence on their bodies; nor have they died of
hunger, since, on examination, they are generally found fat. In 1884,
in Picton, forty-seven dead rats were found lying together under the
floor of the sitting-room in one house. In another thirty-seven were
found dead under the kitchen. The whole town was pervaded with the
odour of dead rats. The average weight of a full-grown specimen is
about 2 oz. The fur on the upper portion of the body is dark brown,
inclining to black; on the lower portion white or greyish-white. They
run awkwardly and slowly on the ground, but run very quickly on the
trees. When suddenly startled or pursued they cry out with fear. The
extremely few females that occur amongst the countless hordes is a
fact that shows that, if breeding does take place at all during these
periods of travel, it must be on a very limited scale.”
I think a probable partial explanation of this problem is that only the
males migrate, while the females, which are producing young at that
very season--the beginning of spring--remain in their usual haunts.
“They do little damage, their food being green vegetables. Though
they enter dwellinghouses and barns, it is evidently not in quest of
food, as shown by corn and other eatables being left untouched by
them.” Rutland adds, “Among English country people, who have the best
opportunity of observing them, it is commonly asserted that in litters
of young rats the males produced outnumbered the females by about seven
to one.”
Meeson describes a plague of rats in 1884: “Nelson and Marlborough--in
other words, the whole of the extreme northern portion of the South
Island of New Zealand--is enduring a perfect invasion. Living rats
are sneaking in every corner, scuttling across every path; their dead
bodies in various stages of decay, and in many cases more or less
mutilated, strew the roads, fields, and gardens, pollute the wells
and streams in all directions. Whatever kills the animals does not
succeed in materially diminishing their numbers. Young and succulent
crops, as of wheat and peas, are so ravaged as to be unfit for and not
worth the trouble of cutting and harvesting. A young farmer the other
day killed with a stout stick two hundred in a couple of hours in his
wheat-field.” Among reasons suggested for the visitation he suggests
the pressure of famine: “Last summer was very wet, and last winter very
cold; the amount of snow lying on the high lands in the interior was
very great. Another is the excessive increase in numbers, producing an
intense struggle for existence.” It is thus seen that his conclusions
are somewhat different from those reached by Mr. Rutland, who did not
think that hunger was an impelling cause. He goes on to say, “I have
examined many of these animals, and have not found a single female.
One of my neighbours has examined two hundred of them, and a Maori, at
the pa beyond Wakapuaka, one hundred, with the same negative result.
Some females have, however, been taken, and in one case they were found
breeding. He is more like a big field-mouse than a Norway rat; and
besides being considerably smaller he is slightly darker in colour, and
less malodorous. He climbs trees and flax-plants, and is phytophagous
rather than carnivorous.”
Hutton, writing in 1887, said, “The rat appears to have invaded Picton
at the end of March, and to have suddenly disappeared by the 20th
April. Old Maoris recognized it as the rat they used to eat in former
times, and said that swarming on to the lowlands periodically was
always characteristic of it. These rats were often noticed climbing
trees. In the Pelorus, where they stopped longer, they built nests,
like birds, in trees.”
Kingsley, in 1894, records it as nesting on the branches of small
trees, 4 ft. to 5 ft. from the ground, near Totaranui, and gives
examples from Motueka, Riwaka, Collingwood, Nelson, and Taranaki.
I myself have seen tall thorn hedges at Whangarei full of their
nests--large, shapeless structures, which at first I thought must have
been made by house-sparrows which had taken to building in hedges.
At the present time black rats are extraordinarily common about
Christchurch. Mr. Speight, the curator, informed me three years ago
that Canterbury Museum was infested with them. A good deal of the
damage said to be done to orchards by opossums is almost certainly the
work of the black rat.
Marriner reports that he met with grey rats at North-west Bay in
Campbell Island, which Waite, of the Canterbury Museum, thought were
probably specimens of _Mus rattus_.
The brown, or Norway, rat (_Mus decumanus_) is ubiquitous, and, though
there is no record of its arrival in New Zealand, it no doubt arrived
here in the earliest days of settlement. Early in last century Russell,
or Kororareka, in the Bay of Islands, was the chief port of the young
colony, and rats must have become very abundant there. Charles Darwin,
who visited the Bay of Islands in 1835, says in his account of the
voyage of the “Beagle,” “It is said that the common Norway rat, in the
short space of two years, annihilated in this north end of the Island
the New Zealand species.” Dieffenbach, writing some time later, said he
never could obtain a native rat, “owing to the extermination carried on
against it by the European rat.” There is no doubt that this species
has had a considerable share in the destruction of the native avifauna,
and it is also responsible for much of the difficulty experienced by
acclimatization societies and private individuals in their attempts to
establish introduced game-birds, but I do not think it is responsible
for the disappearance of the Maori rat.
[Illustration: FIG. 13.--THE BROWN OR NORWAY RAT.]
During visits to Stewart Island and the West Coast Sounds between 1874
and 1880 I was struck by the abundance of these animals in regions
uninhabited and almost unvisited by man. One day I remember that the
late Mr. Robert Paulin and I emerged from the bush on the south side
of Thule, in Paterson Inlet, when the tide was low, exposing a wide
stretch of beach nearly a mile long. We were much impressed by noticing
that the whole beach was alive with large rats, which were feeding on
the shell-fish and stranded animals which the tide had left exposed.
As soon as they saw us they ran for the shelter of the bush; they
were literally in hundreds. I am inclined to think that the rat which
frequents all sheltered beaches on the coast is this common brown
rat, and that it depends on the animal life of the sea-coast for its
livelihood.
In 1868 H. H. Travers reported these brown rats as very abundant in the
Chatham Islands; and Captain Bollons, of the “Hinemoa,” states that
they are very numerous round the homestead on Campbell Island.
A few years ago, when a scare arose about the bubonic plague, a feeble
and intermittent crusade against rats was inaugurated, especially in
Auckland; but it was, as might have been expected, absolutely futile.
It is, of course, well known that rats are the carriers of the plague
germs, or at least that they harbour the fleas which are the real
carriers. In the fifth and sixth chapters of I Samuel there is a
very interesting account of the plague which attacked the cities of
Philistia, and which produced emerods--that is, haemorrhoids or swollen
glands--as a conspicuous symptom. The lords of the Philistines, in
sending back the ark of God to the Israelites, because they thought
it was the cause of the malady which affected them, accompanied it by
models of emerods in gold, and also golden mice. These were probably
golden rats, and seem to show that in these early days, three thousand
years ago, the connection between the plague and the rats was well
recognized.
While brown rats are still very abundant, especially about the towns,
there is no doubt that the spread of weasels throughout the country has
vastly diminished their numbers, especially in the open, for a weasel
prefers a rat to a rabbit any day.