black rat; roof rat
Refers to the species Rattus rattus, a common commensal rodent. In everyday Japanese, クマネズミ is the typical written form.
Black rats are often seen in urban areas.
A roof rat has taken up residence in the attic.
Katakana spelling is common for this animal name; usually written in kana.
Kanji form is rare; the word is usually written in kana.
Compound of 熊 (くま, 'bear') + 鼠 (ねずみ, 'rat/mouse'), likely from its relatively large size and dark color compared to other mice. The exact origin of the name is uncertain.