The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1885-1921, 1907-12-23
HOW RATS
WERE RAlDED
CONTINUES from Paee one.)


numbers, and the decrease is scarcely
| noticed.
Several methods were suggested and
practised for the determination Of the
rats, but most of them have only tenn
porary effect, and cannot be perma-
nent. The suggestion of killing as
many female rats as possible may have
a permanent desired effect by leaving
the polygamous male rats to fight and
kill each other for the possession of
the few remaining females.
Until we can find some definite
means of exterminating the rats per-
manently, We must be satisfied our
| selves TO build our dwellings rat
proof" so as to exclude these unwel-
come creatures away from the abode
! of human beings.
The following article in regard to
i the various behavior of the rats was
given out by the head of the Health
| Department of the city of Toxic: THE
/ house rats increase at an enormous
rate. The female impregnates four
times a year, and in each parturition
/ begets from twelve to fourteen rats.
/ The animal loves her young and feeds
them until they are able to subsist
| themselves as hens do with their
chickens,
The mouse gives birth from twenty
two to twenty-four days after concep-
ton. and begets from four to eight lit
tie ones in each parturition, and i'm
pregnates from FIVE to six times a
year, and in this way female will
have at least thirty little ones in a
year"
The investigation made in one OF the
high schools in Japan gave the follow
ing result:
l. Give birth twenty-one days after
impregnation.
2. Ten days after birth the eyes Will
open, and in 100 days viii have inter
course.
8. A female may have intercourse
seven days after parturition, and give
birth to little ones any time, generally
four to twelve times.
4. In one PARTITION, the house rat
may have about ten little ones; rats
in the cage about six, and field rats
about three.
have much intercourse, and the num-
Der of the offspring decreases. Those
two years old may have only one or
two offspring in each parturition At
ter two years they generally die. The
life limit of the house and field rat
is within three years.
If rats increase in this way without
any interference, the earth would soon
be filled with armies of rats, but the
increasing number is always kept
down by the attacks from human be- |
ings, cats, dogs, mongoose, etc.
Besides they are earnfverous and |
devour each other, the weaker ones
always by the stronger.
The rats can run, climb, and jump !
sideways. Except those living in the |
mud, the animal can climb smooth /
pole, such as bamboo or an iron bar |
Recently an experiment was made to /
test the climbing power of the ami
NAL over a zinc wall, which we use /
at present to enclose. plague-infected /
places to prevent the infected rats /
from escaping outside. i
For this purpose. they selected a /
piece of ground six feet square, and !
surrounded il on four sides by a zinc /
wall. Another zinc wall was erected |
outside of this enclosure, so as TO /
enclose a sTace twelve feet square. and /
then a third which enclosed a space |
eighteen feet square. The height of /
the first or fnnermost wall was 1 foot |
s inches: the middle one feet 2
inches; and the last or outermost one.
8 feet inches. Then FIVE healthy |
rats were selected and put inside the i
innermost space to experiment with /
the climbing and jumping powers of
the animals.
The result was that the animals
could jump over all walls except the
outermost one. of 3 feet inches. The
power of jumping sideways was also
experimental on, and it was found
that the animal can jump across the
distance of feet , inches. It is,
therefore, unnecessary to erect the
zine wall more than four feet high in
order to prevent the rats from escap-
ing outside the infected place, and the
zinc wall must be smooth and with
out nail holes. and the lower end
exactly fit the level of the ground.
In the month of May 1908. an ex-
pertinent was conducted in the harbor
Of Yokohama to test the swimming +
power of the rats in the water. In
the first experiment an animal weigh
ing 235 gins was used, which is a little
larger than the average animal. The
animal sank under the water for a
few. seconds, and then appeared at the
distance of about thirty-f1ve feet. and
to swim eastward. After
eleven minutes the animal seemed TO
grow weaker, and after fifteen minutes
almost exhausted, and after twenty
five minutes stopped swimming en-
tirely and looked apparently dead. 1t
was then taken out of the water and
left on the ground for half an hour,
when it had completely revived, and
came TO life again.
The total distance swan by this
animal was found TO be $40 feet
In the second experiment, two rats
were used at the same time. one
weighing $50 gins. and the other 12o
gins. These animals were let loose
from certain fixed point at exactly
sixteen minutes after ? O'Clock in the
afternoon The first animal lost the
power of swimming after seventeen
r-,iv.v+a- av5 after twenty minutes