What Does a River Otter Look Like?

The North American river otter (Lontra canadensis) is a sleek, semi-aquatic mammal perfectly adapted for life in water.

Physical Description

• Size: 23–36 in (58–91 cm) body; 12–18 in (30–46 cm) tail. Weight: 10–33 lb (4.5–15 kg). Males larger.
• Body: Long, cylindrical, streamlined; short legs; broad, flattened head.
• Fur: Dense, two-layered (guard hairs + underfur), water-repellent. Dark brown to black, lighter on throat/belly.
• Head: Small rounded ears (close underwater), high-set eyes, prominent whiskers (vibrissae) for tactile hunting.
• Tail: Thick, muscular, tapering—acts as rudder and propeller.
• Feet: Fully webbed, five toes with non-retractable claws.

Adaptations

• Can close ears/nostrils underwater
• Nictitating membrane protects eyes
• High metabolism; eats 15–20% body weight daily
• Dives 60+ ft, holds breath 4–8 minutes

River otters inhabit freshwater rivers, lakes, marshes, and coastal estuaries across North America. Playful, curious, and highly social—often seen sliding on mud or snow.