RODENTIA--MICE AND GUINEA-PIGS.
THE MOUSE (_Mus musculus_).
It is probable that the mouse was introduced into New Zealand early in
last century, yet the first notice of the appearance of this familiar
little animal in the North Island is recorded by Dieffenbach, who wrote
as late as 1839. Pastor Wohlers, long a missionary working among the
Natives on Ruapuke, in Foveaux Strait, states that mice were first
brought to that island in the “Elizabeth Henrietta,” which was wrecked
there in 1824, and that even as late as 1873 they continued to be known
as “henriettas.” The late Mr. Robert Gillies, who arrived in Otago
in 1848, writing in 1872, says that it is quite certain there were
no mice in Otago in 1852; but a year or perhaps two years after they
were noticed, in Dunedin first. They quickly travelled south, but the
Molyneux stopped their migration for a time, and it was considerably
later before Molyneux Island (Inch-Clutha) was touched by them. Taylor
White speaks of mice appearing in the Canterbury Plains in the early
days of settlement (from 1855 onwards) “suddenly in thousands.” In
1866, during a discussion which arose at a meeting of the Canterbury
Acclimatization Society as to the reported destruction of small birds
by hawks, Mr. W. T. L. Travers reported “that he had opened a large
number of hawks, and in all cases found their food to consist entirely
of mice and grasshoppers.”
The mouse has never been found very far from the haunts of men, either
in this country or elsewhere. It is abundant in all settled parts, and
is also common on the Auckland, Antipodes, and Campbell Islands. Though
it follows man so closely, it frequently stays in localities where
men have been and have left, and there it is apt to have a bad time.
Mr. Philpott, writing to me on the 2nd January, 1918, said, “There is
a plague of mice in the district west of the Waiau. From Bluecliff
to the Knife and Steel, near the Big River and beyond, each hut [the
Government huts on the now abandoned telephone track to Puysegur Point]
was overrun with them. And not only at the huts, but on the beach and
in the dense bush, wherever we went, they were plentiful. At the Hump,
near Lake Hauroto, they were as numerous as elsewhere. This prevalence
of mice is certainly not usual; I have been on the Hump four or five
times since 1911, and last year tramped along to the Knife and Steel,
but, apart from an odd one or two, no mice were in evidence on former
trips. One noticeable thing about these little creatures was their
boldness: they were evidently very hungry. The wekas caught many of
them, swallowing them whole, head first.”
How terrible a pest these rodents can be is shown by the state of
affairs which has prevailed in the wheat-growing districts of Australia
during the past season or two. The following note, taken from the
Melbourne _Age_ of the 17th July, 1917, gives some idea of the
dimensions the pest has reached: “At Brooklyn there are nearly seven
million bags of wheat, forming three and a half miles of stacks, and
it is estimated that close on two million bags have yet to be railed
thither from country stations. At Spotswood three million bags, most
from the 1915-16 crop, are stacked.... The mouse plague in its myriads
has attacked the Brooklyn stacks. The very air reeks with the smell of
the mice, dead and alive. Daily to Brooklyn roll from seven hundred to
eight hundred railway-trucks, loaded at the country stations mainly
in the mouse-riddled areas of the Wimmera and the Mallee. From the
Goulburn Valley the trucks bring with them, it is observed, mice that
are few in comparison with those from the Wimmera and the Mallee. Every
truck from these two regions contributes its mice to the swarming
community at Brooklyn. And of the manner of the reception of these mice
the instances afforded on an inspection on a week-day are at least
suggestive. The average truck, when rolled alongside the wheat-stacks,
is received by a handful of labourers. The bags are hauled up by
tackle from truck to stack. When the last bag is lifted the doors of
the truck are thrown open, and the chaff and the spoilt wheat broomed
out. With the waste come flying out the mice--no great number in some
trucks, but, clearly, on the average delivery of trucks a day, adding
hundreds of mice to the pest, which has bitten deeply into the stacks
at Brooklyn. Scattering, scampering, the mice race down the rails. A
fox-terrier or two, wearing a _blasé_ demeanour, condescend to catch
a couple of mice as an example to the others. The rest of the new
arrivals find shelter in the base of the wheat-stacks, or the low
pile of damp, reeking bags of wheat awaiting reconditioning. Little if
any effort seems to be made by the labourers to check the pest in an
ordinary truck; and, indeed, a great deal of effort would be needed
to be effective, and the reception and despatch of trucks must be
inevitably delayed. Only when a badly infested truck, smeared with the
flour of mouse-gnawn wheat, announces its contents by a vile reek of
rotting mouse--an announcement beyond all risk of contradiction--it is
detached, hauled off to another track, and left loaded to await special
treatment.”
Two methods are adopted in Victoria to cope with the pest in the
wheat-trains. One is to plug all the holes in the truck, place a sack
in each corner with its mouth propped open with an iron hoop, and then
proceed to lift the bags of wheat out of the truck on to the stack. The
escaping mice jump into the sacks until they are nearly half-full. But
if the mice are too numerous to be dealt with in this way, then they
are gassed in the truck. I am not sure whether carbon disulphide or
carbon dioxide is employed--probably the former. This takes at least
an hour, and perhaps ten thousand mice are afterwards shovelled out of
each truck; and, as hundreds of trucks full of wheat were arriving at
Brooklyn each day, it is easily seen that the plague certainly was not
stayed. What happens at Brooklyn has been happening in other parts of
Australia, and we may be thankful that in New Zealand we have no such
gigantic pests to cope with.
As the mouse breeds all the year round and produces five or six young
at a birth, its rapid increase under favourable circumstances is easily
understood.
THE GUINEA-PIG (_Cavia porcellus_).
On the banks of the Rio de la Plata, and in the country lying to the
northwards, a little animal, considered by many naturalists to be the
wild form from which our domesticated guinea-pig is derived, is found
in thousands. It is known as the “restless cavy.” It generally lives
in moist situations, usually near the border of the forest, but never
in the forest itself or in the open fields. Other authorities consider
that the name “guinea-pig” is a corruption of Guiana-pig, and that the
first specimens may have come from that part of America. The prevalent
colours of the guinea-pig, as is well known, are white, black, and
yellow, and in this respect it differs a good deal from the “restless
cavy.”
It is hardly correct to include the guinea-pig among the wild animals
of New Zealand, as, although it has been frequently liberated, it has
never succeeded in establishing itself. At one time I had a number of
guinea-pigs running wild in my garden in Maori Hill, and noticed that
violets growing among the grass increased remarkably all the time they
were about. The guinea-pigs kept the grass very closely nibbled, but
would not touch the violets. These animals had a well-sheltered run
under a thick mass of periwinkle which grew along a raised bank. They
throve remarkably till a host of little ones, not much bigger than the
end of one’s thumb, began to appear. This was too much for the cats
in the neighbourhood. These creatures began to haunt the garden day
and night. They soon ate all the little ones, and, having acquired a
taste for this kind of game, they never stopped till they had destroyed
all the stock but a few old bucks. There is no reason why guinea-pigs
should not become wild in this country, except for the prevalence of
cats.
The only record I find of the introduction of these animals into this
country is by the Auckland Acclimatization Society in 1869; but they
have been repeatedly brought in by dealers for the last fifty or sixty
years. I believe that guinea-pigs are very good for food, for they are
very dainty feeders. But there is a considerable prejudice against them
on the part of most people. I had a bachelor acquaintance in London
who used to give very _recherché_ dinners to his male friends. On one
occasion they got a dish of a new and very palatable kind, which they
all enjoyed, until they learned that they had been eating guinea-pig,
when some of them highly resented their host’s experimenting upon them.
But it was only prejudice from which they suffered. They reminded me
of the lady who enjoyed stewed eel until she learned what she had been
eating, when she promptly retired from the table and managed to get
sick.
The family of the cavies, to which the guinea-pig belongs, is chiefly
characterized by the form of the teeth. The fore feet have four and
the hind feet three toes, all armed with hoof-like nails. The tail is
rudimentary or wanting; hence the common warning to children that if
one lifts a guinea-pig by the tail the eyes will drop out.