giant otter; giant river otter
Refers specifically to the species Pteronura brasiliensis, a large South American otter.
Giant otters inhabit rivers in South America.
I saw a group of giant otters at the zoo.
Kanji spelling is rare and may not be widely recognized; lists it not high priority.
Compound of 大 (おお, 'big') and カワウソ (かわうそ, 'otter'). The exact origin of カワウソ is uncertain, but it is a native Japanese word.