otter; Eurasian otter
General term for otter, especially the Eurasian otter (Lutra lutra).
Otters are good at catching fish in rivers.
Japanese river otter
Specifically the Japanese river otter (Lutra lutra whiteleyi), a subspecies once found in Japan, now considered extinct.
The Japanese river otter is thought to be extinct.
Asian small-clawed otter
European otter; Eurasian otter; common otter
The word is usually written in kana; katakana is common in biological contexts.
Single-character kanji form; also read うそ, おそ, or だつ in restricted contexts.
Hiragana spelling, also common.
Kanji spelling using 川 (river) and 獺 (otter). Rarely used.
Alternate kanji spelling using 河 (river). Rarely used.
Compound of 川 (kawa, 'river') and 獺 (uso, 'otter'). The reading うそ is an older native Japanese word for otter, now mostly replaced by かわうそ.