齧歯類(げっしるい)

げっしるい
noun
rodent; rodents (Rodentia)
animal-mammalscience
1. rodent; rodents (Rodentia)
The biological order Rodentia, comprising mammals such as mice, rats, squirrels, beavers, and porcupines that share continuously growing front incisors used for gnawing. Used both as a technical zoological term and in everyday writing about animals.
鼠(ねずみ)は齧歯類(げっしるい)だ。
Mice are rodents.
リスや兎(うさぎ)も齧歯類(げっしるい)に含(ふく)まれると思(おも)われがちだ。
Squirrels and rabbits are often mistakenly thought to be included among rodents.
齧歯類(げっしるい)は哺乳類(ほにゅうるい)の中(なか)で最(もっと)も種類(しゅるい)が多(おお)い。
Rodents are the most species-rich group within mammals.
齧歯類(げっしるい)の前歯(まえば)は一生(いっしょう)伸(の)び続(つづ)けるため、常(つね)に何(なに)かを齧(かじ)って削(けず)らなければならない。
Because rodents' incisors grow continuously throughout their lives, they must constantly gnaw on something to wear them down.

Composed of 齧(げっ) (to gnaw), 歯(し) (tooth), and the suffix 類(るい) (kind; class; -idae). Literally 'the gnawing-tooth class,' the name highlights the defining trait of the order — a single pair of continuously growing incisors in each jaw.

Usage

A biological category term, used in science writing, nature documentaries, veterinary contexts, and pet-shop literature. Like other 〜類(るい) group names (哺乳類(ほにゅうるい) mammals, 爬虫類(はちゅうるい) reptiles), it sounds technical but is fully comprehensible to general readers. Note that rabbits (兎(うさぎ)) are NOT rodents — they belong to the order Lagomorpha (兎形目(うさぎがたもく) or ウサギ目(もく)) — though many laypeople assume otherwise.

Common collocations

Similar words

  • 哺乳類(ほにゅうるい): mammals — the broader class to which rodents belong
  • 鼠(ねずみ): mouse; rat — the most familiar example of a rodent
  • 兎形目(うさぎがたもく): order Lagomorpha — the order containing rabbits and hares (often confused with rodents)
  • 爬虫類(はちゅうるい): reptiles — a parallel taxonomic group of similar formality

Related Words

Compare: 哺乳類(ほにゅうるい) (mammals)
Compare: 鼠(ねずみ) (mouse)
Compare: 爬虫類(はちゅうるい) (reptiles)
general
Added 2026.4.14 5:17 · Revised 2026.9.2 13:02
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