Cottonmouths (Agkistrodon piscivorus) are venomous semi-aquatic snakes often referred to as “water moccasins.” They have large, triangular heads with a dark line through the eye, elliptical pupils, and large jowls due to the venom glands. They are large – typically 24 - 48 in (61 - 122 cm), occasionally larger, keeled-scaled, heavy-bodied snakes. Their coloration is highly variable: they can be beautifully marked with dark crossbands on a brown and yellow ground color or completely brown or black. Older adults are often dark and solid-colored whereas the juveniles are brightly patterned with a sulphur yellow tail tip that they wiggle to attract prey. The belly typically has dark and brownish-yellow blotches with the underside of the tail being black. As pit-vipers they have facial pits that sense heat and are used to detect prey and predators. Male cottonmouths are larger than females.