t unfrequently
the case--will not hesitate to attack living creatures, and show but
little fear of either cat or dog. They often commit extensive damage
upon articles of the cargo, and are thus a great nuisance in a ship,
especially when she has not been properly overhauled and cleaned out
before loading for a voyage. These ship-rats are the sort known as
"Norway rats," on account of a belief that they were first brought to
England in Norwegian ships; but whether they originated in Norway or
elsewhere, it matters little, as they are now universally distributed
over the whole globe, and I believe there is no part of the earth, where
ships have touched, that Norway rats are not found in abundance. If
Norway was in reality the country of their origin, then it follows that
all climes are alike to them, since they are especially abundant and
thriving in the hot tropical climates of America. Seaport towns in the
West Indies and the continents of both North and South America are
infested with them; and so great a nuisance are they deemed in some of
these places, that a "rat-bounty" is usually offered by the municipal
authorities for their destruction. Notwithstanding this premium for
killing them, they still exist in countless numbers, and the wooden
wharves of these American seaports appear to be their true _harbours of
refuge_!

The Norway rats are not individually large rats. Occasionally very
large ones are found among them, but these are exceptional cases. They
are in general less distinguished for size, than for a fierce and
spiteful disposition, combined with a great fecundity, which of course
renders them exceedingly numerous and troublesome. It has been observed
that wherever they make their appearance, in a few years the rats of all
other species disappear; and it is therefore conjectured that the Norway
rats destroy the other kinds! Weazels are no match for them--for what
they lack in individual strength is amply compensated for by their
numbers--and in these hot countries they outnumber their enemies in the
proportion of hundreds to one. Even cats are afraid of them; and in
many parts of the world the cats will shy away from an encounter with
Norway rats, choosing for their prey some victim of a milder
disposition. Even large dogs, unless specially set on, will prefer to
pass and give them a wide berth.

One fact about the Norway rat is peculiar: it appears to know when it
possesses the advantage. Whe