**Description:** Semi-aquatic mammals with elongated, streamlined bodies and thick, water-repellent brown fur. They feature webbed feet and a powerful, tapered tail used for propulsion.
**Size & Weight:** 35–53 inches long. Weigh 11–30 lbs.
**Sexual Dimorphism:** Males are roughly 5% larger than females on average.
**Life Cycle:** Pups are born in late winter or early spring and are taught to swim at about two months of age.
**Habitat:** Found along the Allegheny River, Tionesta Creek, and larger forest tributaries.
**Identification:** Look for "slides" on muddy or snowy banks. They are highly social and playful, often seen in small family groups.