Source : Webster's Revised Unabridged Dictionary (1913)

Rat \Rat\, 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 the several species of small rodents of
      the genus {Mus} and allied genera, larger than mice, that
      infest houses, stores, and ships, especially the Norway,
      or brown, rat ({M. Alexandrinus}). These were introduced
      into Anerica from the Old World.

   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 wide 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 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 America 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 {N. Floridana}, common in the
      Southern United States. Its feet and belly are white.

Hedgehog \Hedge"hog`\, n.
   1. (Zo["o]l.) A small European insectivore ({Erinaceus
      Europ[ae]us}), and other allied species of Asia and
      Africa, having the hair on the upper part of its body
      mixed with prickles or spines. It is able to roll itself
      into a ball so as to present the spines outwardly in every
      direction. It is nocturnal in its habits, feeding chiefly
      upon insects.

   2. (Zo["o]l.) The Canadian porcupine.[U.S]

   3. (Bot.) A species of {Medicago} ({M. intertexta}), the pods
      of which are armed with short spines; -- popularly so
      called. --Loudon.

   4. A form of dredging machine. --Knight.

   {Hedgehog caterpillar} (Zo["o]l.), the hairy larv[ae] of
      several species of bombycid moths, as of the Isabella
      moth. It curls up like a hedgehog when disturbed. See
      {Woolly bear}, and {Isabella moth}.

   {Hedgehog fish} (Zo["o]l.), any spinose plectognath fish,
      esp. of the genus {Diodon}; the porcupine fish.

   {Hedgehog grass} (Bot.), a grass with spiny involucres,
      growing on sandy shores; burgrass ({Cenchrus
      tribuloides}).

   {Hedgehog rat} (Zo["o]l.), one of several West Indian
      rodents, allied to the porcupines, but with ratlike tails,
      and few quills, or only stiff bristles. The hedgehog rats
      belong to {Capromys}, {Plagiodon}, and allied genera.

   {Hedgehog shell} (Zo["o]l.), any spinose, marine, univalve
      shell of the genus {Murex}.

   {Hedgehog thistle} (Bot.), a plant of the Cactus family,
      globular in form, and covered with spines
      ({Echinocactus}).

   {Sea hedgehog}. See {Diodon}.