鼠类；长鼻袋鼠

Rat \Rat\ (r[a^]t), n. [AS. r[ae]t; akin to D. rat, OHG. rato,
ratta, G. ratte, ratze, OLG. ratta, LG. & Dan. rotte, Sw.
r[*a]tta, F. rat, Ir. & Gael radan, Armor. raz, of unknown
origin. Cf. {Raccoon}.]
1. (Zo["o]l.) One of several species of small rodents of the
genus {Rattus} (formerly included in {Mus}) and allied
genera, of the family {Muridae}, distinguished from mice
primarily by being larger. They infest houses, stores, and
ships, especially the Norway rat, also called {brown rat},
({Rattus norvegicus} formerly {Mus decumanus}), the black
rat ({Rattus rattus} formerly {Mus rattus}), and the roof
rat (formerly {Mus Alexandrinus}, now included in {Rattus
rattus}). These were introduced into America from the Old
World. The white rat used most commonly in laboratories is
primarily a strain derived from {Rattus rattus}.
[1913 Webster +PJC]

2. A round and tapering mass of hair, or similar material,
used by women to support the puffs and rolls of their
natural hair. [Local, U.S.]

3. One who deserts his party or associates; hence, in the
trades, one who works for lower wages than those
prescribed by a trades union. [Cant]

Note: ``It so chanced that, not long after the accession of
the house of Hanover, some of the brown, that is the
German or Norway, rats, were first brought over to this
country (in some timber as is said); and being much
stronger than the black, or, till then, the common,
rats, they in many places quite extirpated the latter.
The word (both the noun and the verb to rat) was first,
as we have seen, leveled at the converts to the
government of George the First, but has by degrees
obtained a wider meaning, and come to be applied to any
sudden and mercenary change in politics.'' --Lord
Mahon.

{Bamboo rat} (Zo["o]l.), any Indian rodent of the genus
{Rhizomys}.

{Beaver rat}, {Coast rat}. (Zo["o]l.) See under {Beaver} and
{Coast}.

{Blind rat} (Zo["o]l.), the mole rat.

{Cotton rat} (Zo["o]l.), a long-haired rat ({Sigmodon
hispidus}), native of the Southern United States and
Mexico. It makes its nest of cotton and is often injurious
to the crop.

{Ground rat}. See {Ground Pig}, under {Ground}.

{Hedgehog rat}. See under {Hedgehog}.

{Kangaroo rat} (Zo["o]l.), the potoroo.

{Norway rat} (Zo["o]l.), the common brown rat. See {Rat}.

{Pouched rat}. (Zo["o]l.)
(a) See {Pocket Gopher}, under {Pocket}.
(b) Any African rodent of the genus {Cricetomys}.

{Rat Indians} (Ethnol.), a tribe of Indians dwelling near
Fort Ukon, Alaska. They belong to the Athabascan stock.

{Rat mole}. (Zo["o]l.) See {Mole rat}, under {Mole}.

{Rat pit}, an inclosed space into which rats are put to be
killed by a dog for sport.

{Rat snake} (Zo["o]l.), a large colubrine snake ({Ptyas
mucosus}) very common in India and Ceylon. It enters
dwellings, and destroys rats, chickens, etc.

{Spiny rat} (Zo["o]l.), any South American rodent of the
genus {Echinomys}.

{To smell a rat}. See under {Smell}.

{Wood rat} (Zo["o]l.), any American rat of the genus
{Neotoma}, especially {Neotoma Floridana}, common in the
Southern United States. Its feet and belly are white.

kangaroo rat \kangaroo rat\ n. (Zool.)
A jumping rodent of the genus {Dipodomys} of the family
{Heteromyidae}, which lives in arid regions of Mexico and the
western U. S.
[PJC]

2. (Zool.) An Australian mammal of the genus {Notomys}.
[PJC]

3. (Zool.) a small ratlike Australian kangaroo of the genus
{Potorous}, also called the {potoroo}.
[PJC]


Potoroo \Po`to*roo"\, n. (Zo["o]l.)
Any small kangaroo belonging to {Hypsiprymnus}, {Bettongia},
and allied genera, native of Australia and Tasmania. Called
also {kangaroo rat}.