underfur

uncountable usually

The thick, soft undercoat of some mammals, especially those that spend time in the water

Japanese Meaning

厚く柔らかな下毛（特に水中に棲む哺乳類の下毛）

The river otter's thick underfur kept it warm during the icy morning swim.

カワウソの厚く柔らかい下毛が、氷のように冷たい朝の泳ぎの間も体を温かく保った。

Sense（1）

The thick, soft undercoat of some mammals, especially those that spend time in the water

underfurs

（ plural ）