Felis Images / Smooth-coated otter (Lutrogale perspicillata), two at edge of forest. Otter walking, out of focus otter nose in foreground. Andhra Pradesh, India. Photo Anjani Kumar/Felis Images

Felis Images / Smooth-coated otter (Lutrogale perspicillata) at edge of forest. Andhra Pradesh, India. Photo Anjani Kumar/Felis Images

Ben Cranke / Smooth-coated otter (Lutrogalle perspicillate) about to enter a marsh at dawn, Dudhwa National Park, Uttar Pradesh, India. Photographed using a camera trap.

Tony Wu / Smooth-coated otters (Lutrogale perspicillata) eating fish in the early morning in Kallang River, Singapore

Tony Wu / Smooth-coated otters (Lutrogale perspicillata) two young, heading back to shelter, Kallang River, Singapore

Tony Wu / Smooth-coated otter (Lutrogale perspicillata) with young otters, socializing in the early morning, Kallang River, Singapore

Daniel Heuclin / Smooth otter (Lutrogale perspicillata) captive, occurs in South East Asia.

Luke Massey / Smooth coated otters (Lutrogale perspicillate) fighting, Singapore. November.

Luke Massey / Smooth coated otters (Lutrogale perspicillate) feeding on fish, Singapore. November.

Luke Massey / Smooth coated otters (Lutrogale perspicillate) fighting, Singapore. November.

Luke Massey / Smooth coated otters (Lutrogale perspicillate) fighting, Singapore. November.

Luke Massey / Smooth coated otters (Lutrogale perspicillate) fighting, Singapore. November.