Keelback Tropidonophis mairii (also known as freshwater snake)


Caution: this snake closely resembles the venomous and dangerous rough-scaled snake.

The keelback or freshwater snake's head and neck are grey-green or brown with the body grey-green to brown typically with cross-bands of darker flecks. Upper body scales are strongly keeled or ridged. A loreal scale is present (a scale situated between the nasal scale and scales directly in front of eye), distinguishing it from the venomous rough-scaled snake. The keelback is found in and around creeks, rivers and marshlands. It feeds largely on frogs (including cane toads) that it actively pursues during the day or night. It grows to an average length of 0.5m.

Tropidonophis mairii, commonly known as the common keelback, Mair's keelback, the keelback, or the freshwater snake, is a species of nonvenomous snake found throughout Northern Australia.


The specific name, mairii, is in honor of "Dr. Mair", an army surgeon with the 39th Regiment of Foot, who collected the holotype


T. mairii resembles two venomous snakes, the taipan and the rough-scaled snake. T. mairii rarely grows over 1 m (39 in) in total length (including tail).


Mair's keelback feeds mainly on amphibians and small lizards. It is one of the few snakes that can eat cane toads (Rhinella marina), up to a certain size, without being harmed.