Northern water snake The belly also varies in color. It can be white, yellow, or gray. Usually it also has reddish or black crescents. The northern water snake is nonvenomous and harmless to humans, but superficially resembles the venomous cottonmouth and is often killed unnecessarily as a result of this mistaken identity. The two can be easily distinguished by morphological traits: the water snake has a longer, more slender body and a flattened head the same width as the neck, round pupils, and no heat-sensing pits. The cottonmouth has a fatter body, a wedge-shaped head with prominent venom glands that are wider than
Mulga snake Mulga snake The mulga snake ("Pseudechis australis") is a species of venomous snake found in Australia. It is one of the longest venomous snakes in the world, and is the second-longest in Australia (surpassed only by the coastal taipan). Its alternative common name is king brown snake, although it is a species in the genus "Pseudechis" (black snakes) and only distantly related to true brown snakes. The species was first described by John Edward Gray in 1842, who placed it in the genus "Naja" (cobras). In 1955, Roy Mackay concluded that several species previously described were synonymous with "P. australis".