Translation guide
A quadruped is an animal that walks on four legs. In Japanese, the most common way to express this is with the noun 四足動物 (しそくどうぶつ), but there are also more technical or descriptive terms.
The speaker wants to refer to any animal that walks on four legs, in a neutral or everyday context.
This is the standard, neutral term for 'quadruped' in Japanese. It literally means 'four-legged animal' and is widely understood.
犬は四足動物です。
Dogs are quadrupeds.
四足動物の多くは哺乳類です。
Many quadrupeds are mammals.
A more colloquial or descriptive term, often used in everyday speech. It can also refer to the act of crawling on all fours (as a human), so context is important.
うちの猫は四つ足で走る。
Our cat runs on all fours.
A more technical or literary term, often used in zoological contexts. It specifically means 'quadrupedal beast'.
この地域には多くの四足獣が生息している。
Many quadrupeds inhabit this region.
The speaker wants to describe an animal as having four legs, often in contrast to bipeds or other animals.
This is an adjectival phrase meaning 'four-legged'. It is very common and natural when describing animals.
四本足の動物は安定している。
Four-legged animals are stable.
あの四本足のロボットはすごい。
That four-legged robot is amazing.
A more concise, slightly formal adjectival phrase. Often used in written or technical descriptions.
四足の哺乳類を観察した。
We observed quadrupedal mammals.
The speaker wants to describe a human crawling or walking on hands and knees, like a quadruped.
This is the standard expression for 'on all fours' when referring to humans. It is used for crawling or being on hands and knees.
赤ちゃんが四つん這いで動いている。
The baby is moving on all fours.
彼は四つん這いで床を探した。
He searched the floor on all fours.
Can also be used for humans, but it's less common than 四つん這いで and might sound slightly childish or animal-like.
子供が四つ足で歩いている。
The child is walking on all fours.
四足動物 (しそくどうぶつ) is the standard, formal term for 'quadruped' as a biological category. 四つ足 (よつあし) is more colloquial and can also refer to the four legs themselves or the act of being on all fours. Use 四足動物 in academic or neutral contexts, and 四つ足 in casual conversation about animals or when describing a crawling posture.
While 四足動物 refers to four-legged animals, using 四足 (しそく) to describe a human would be odd unless you are literally talking about crawling on all fours. For humans, use 四つん這い (よつんばい) for the posture.